Enhanced charge carrier transport and defects mitigation of passivation layer for efficient perovskite solar cells

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Nature Communications volume 15, Article number: 8620 (2024 ) Cite this article cnc turning centers

Surface passivation has been developed as an effective strategy to reduce trap-state density and suppress non-radiation recombination process in perovskite solar cells. However, passivation agents usually own poor conductivity and hold negative impact on the charge carrier transport in device. Here, we report a binary and synergistical post-treatment method by blending 4-tert-butyl-benzylammonium iodide with phenylpropylammonium iodide and spin-coating on perovskite surface to form passivation layer. The binary and synergistical post-treated films show enhanced crystallinity and improved molecular packing as well as better energy band alignment, benefiting for the hole extraction and transfer. Moreover, the surface defects are further passivated compared with unary passivation. Based on the strategy, a record-certified quasi-steady power conversion efficiency of 26.0% perovskite solar cells is achieved. The devices could maintain 81% of initial efficiency after 450 h maximum power point tracking.

The last decade has seen the incredible development of perovskite solar cells (PSCs)1,2,3,4,5,6,7,8, with the reported highest certified power conversion efficiency (PCE) approaching 26%9 based on composition engineering8,10,11,12,13, crystal growth modulation14,15 and surface passivation5,16,17, which demonstrates nearly the same level as commercial crystalline silicon solar cells18. Among these strategies, surface passivation is becoming the last but crucial for fabricating PSCs with excellent performances19.

In our previous work, phenethylammonium iodide (PEAI) was applied onto the surface of perovskite film to reduce the defect density and suppress the nonradiative recombination of holes and electrons5. Two-dimensional (2D) perovskite20,21, inorganic compound22,23 and polymer24 were reported as passivation agents as well. Those materials usually show low conductivity, which could impede the charge transfer in devices, even though the passivation layers were normally ultrathin. This should be one of the reasons why fill factor (FF) increased at a very slow rate in the PCE development process compared with short-circuit current density (JSC) and open-circuit voltage (VOC) and lags behind the Shockley-Queisser (S-Q) limit value25,26.

Considering the trade-off between defect passivation and charge transport, a passivation material holding ability to extract and transmit charge carriers efficiently should be developed. Sargent et al. reported a series of semiconducting polymer to replace the conventional insulator-based passivation agent and the flat-band alignment enabled a better charge transport ability with a FF as high as 83% achieved on PSC27. White et al. modified the passivation layer distribution and built charge transport pathways inside the passivation layer by introducing the nanopatterned electron transport layer, thus a FF reaching 83.9% could be realized thanks to the improved charge transport process28.

In this work, we propose a mixed organic halide salt system for binary and synergistical post-treatment (BSPT) of RbCl-doped FAPbI3 (FA: HC(NH2)2). Specifically, we blended 4-tert-butylphenylmethylammonium iodide (tBBAI)29 with phenylpropylammonium iodide (PPAI)30 in isopropanol (IPA), and the solution was spin-coated onto the perovskite surface for BSPT. Previously, some groups have reported similar combined passivants strategy and mainly focused on the nonradiative recombination loss reduction effect referring to the decreased defect state density31,32,33. We observed that surface defects were further suppressed in our BSPT films compared with PPAI unary passivation as well. More importantly, the crystallinity of passivation layer was prominently strengthened, and the molecular configuration with more ordered packing was achieved through BSPT method, which benefitted the hole transfer from perovskite to HTL. An accelerating electrical field was formed from perovskite to passivation layer, and the energy level of perovskite was more suitable for HTL after BSPT, facilitating the hole extraction. As a result, we achieved a certified 26.0% PCE on normal (n-i-p) planar PSCs. The devices could maintain 81% of the original PCE after 450 h maximum power point (MPP) tracking.

The perovskite film was deposited through a modified two-step method according to our previous report8. PPAI, tBBAI or the mixed were dissolved directly in IPA, and the precursor solution was spin-coated on perovskite film without further annealing. The device structure employed in our research and the molecular configuration of PPAI and tBBAI are schematically illustrated in Fig. 1a. The complete device fabrication process is diagrammed in Supplementary Fig. 1.

a Diagram of PSC structure used in this study with molecular structure of PPAI and tBBAI. b GIXRD patterns at small angle region for pristine perovskite film, perovskite with PPAI, tBBAI and PPAI/tBBAI BSPT post-treatment. c Conventional XRD patterns at small angle region for pristine perovskite film, perovskite with PPAI, tBBAI and PPAI/tBBAI BSPT post-treatment, respectively. a.u. arbitrary units. d–f 2D GIWAXS patterns of pristine perovskite film, perovskite with PPAI unary post-treatment and perovskite with BSPT. g The radial distribution function (RDF) in the PPAI unary and PPAI-tBBAI blended film based on AA-MD simulation results. h The interaction energy in the PPAI unary and PPAI-tBBAI blended film according to AA-MD simulation results. Sum (Blend) refers to the total interaction energy between all molecules in the BSPT film. i Possible energy band structure and hole transfer mechanism of perovskite with BSPT. The HOMO level of Spiro-OMeTAD is drawn from our previous report75.

We first implemented grazing incident X-ray diffraction (GIXRD) characterization to detect the surface crystallization condition (Fig. 1b and Supplementary Fig. 2). The post-treatment of perovskite film was mainly reflected on the new diffraction peaks in the small angle region, while diffraction peaks corresponding to perovskite lattice planes remained virtually the same, implying that the surface treatment held little effect on perovskite. For PPAI unary treatment, a new peak located at 4.76° was observed. A tiny peak of 4.42° emerged on tBBAI unary treated film, coherent with previous report34. When we mixed tBBAI with PPAI and applied BSPT strategy on perovskite film, a new peak located at 4.55° appeared, which fell into the region between 4.42° and 4.76°. We believed that the phenomenon could be explained on the basis of Vegard law, referring to a linear variation of crystal lattice constant when molecular with different size dissolved together. When depositing a single BSPT layer on glass substrate, the diffraction peak at approximately 4.55° could still be observed (Supplementary Fig. 3), indicating that the BSPT layer generally exists in the intrinsic mode when deposited on perovskite surface rather than reacting with perovskite. We further compared the GIXRD peak positions of BSPT perovskite films with different weight ratios between tBBAI and PPAI (Supplementary Fig. 4). We could see from the graph that when tBBAI occupied a larger concentration part, the low-angle diffraction peak was smaller and when PPAI occupied a larger concentration part, the low-angle diffraction peak turned to be larger, which fitted well with the Vegard law. Thus, the new peak after BSPT could indicate a full fusion of the two organic halide salt rather than physical blend. We also noticed that the diffraction intensity at 4.55° significantly enhanced compared with the diffraction intensity at 4.76° in PPAI unary passivation condition. Since the diffraction intensity at 4.42° was weak on tBBAI unary post-treatment film, it could be safe to conclude that the strong intensity signal at 4.55° was indeed due to the improved crystallinity of passivation layer when tBBAI was added into PPAI rather than simply concentration increase, which should be conducive to charge carrier transport process. The I-V measurements of the passivation layers confirmed the better charge transport property of BSPT layer (Supplementary Fig. 5). Conventional X-ray diffraction (C-XRD) results (Fig. 1c and Supplementary Fig. 6) also confirm this finding.

To investigate the crystallization orientation of passivation layer, we further performed grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements35 (Fig. 1d–f). We could calculate that the scattering wave vector q was 3.39 nm−1 and 3.24 nm−1 for the characteristic diffraction peaks in PPAI unary and BSPT conditions, respectively. The corresponding Bragg scattering spots are pointed out using the red arrows in Fig. 1e, f. The Bragg spot along qz is indicative of a parallel orientation relative to the substrate36,37. We inferred that the passivation agents could grow in a layer-by-layer structure mode on the perovskite film and the π-π bonding (large π bond) in the phenyl functional group of the passivation agents could facilitate the charge transfer along the vertical orientation. For BSPT condition, the stronger Bragg spot signal intensity could imply a more parallel molecular orientation relative to the substrate and the more ordered packing situation would be beneficial for charge transport process38. The X-ray photoelectron spectroscopy (XPS) was applied to detect the surface state of perovskite before and after post-treatment (Supplementary Fig. 7). In the C 1s core-level energy spectra, the much more intense peak corresponding to C-C bonds after BSPT could be attributed to the large total concentration of passivators, which manifested that both tBBAI and PPAI remained on the surface of perovskite in the BSPT case. The C=O bonds were mostly eliminated after post-treatment, consistent with previous report5. The π-π bonding signal was from the phenyl functional group in passivation agent and the stronger signal intensity in BSPT film may imply an improved charge carrier transport process, which proved the GIWAXS results. From Pb 4f and I 3d core-level energy spectra, we could calculate the Pb:I ratio of each condition. The highest Pb:I ratio in BSPT sample could indicate the full filling of iodine vacancies at perovskite surface, which should bring the best defect passivation function5.

To uncover the interaction between tBBAI and PPAI as well as the final molecular packing configuration of BSPT, all-atom molecular dynamics (AA-MD) simulation was performed39,40,41. Calculation details can be found in the “Methods” part. For a quantitative analysis, the radial distribution function (RDF, g(r)) of partial centroids between the center of mass (COM) was plotted, which measures the probability of finding a particle at a certain distance from a reference particle. A higher g(r) peak signifies a greater packing density at a specific distance. As shown in Fig. 1g, the intensity of the first peak of g(r) for PPAI in the PPAI unary film localized at the distance of 3.0 Å was significantly lower than that between PPAI and tBBAI in the blended film, thus the packing patterns between PPAI and tBBAI in the mixed film were more dominant than between PPAI and PPAI in the PPAI unary film. This could indicate that a more structured molecular packing system emerged between PPAI and tBBAI in the blended film than in the PPAI unary film, in accordance with the stronger diffraction peak signal from XRD measurement and the stronger Bragg spot signal along qz from GIWAXS measurement shown in BSPT condition than PPAI unary post-treatment condition. Additionally, the peak intensity of g(r) for PPAI in the blended film was less pronounced than in the pure PPAI film, as the peak distance expanded to 3.6 Å in the mixed film. This suggested that the packing patterns of PPAI in the unary film were superseded by those between PPAI and tBBAI in the blended film. The result could explain the XRD diffraction peak angle shift after adding tBBAI into PPAI when applying BSPT strategy. The interaction energy data was also gathered in the unary and blended film. Interestingly, after adding the tBBAI molecules, the interaction energy between PPAI molecules reduced in the mixed film compared with that in the PPAI unary film. Most importantly, the interaction between PPAI and tBBAI was stronger than that between PPAI and PPAI in the mixed film, suggesting that PPAI may prefer to interact with tBBAI to create an ordered pattern in the blended situation (Fig. 1h), which further proved aforementioned outcomes. The molecular conformation in the film containing both PPAI and tBBAI was extracted from the AA-MD trajectories, showing that PPAI molecules could pack well with tBBAI (Supplementary Fig. 8a). Besides, we calculated the distribution of angles between the PPAI benzene plane and tail (Supplementary Fig. 8b) and fitted the data with a Gaussian function. It is worth noting that the peak angle slightly increased to 75.4o after adding tBBAI, which was slightly lower when the tBBAI was not present, implying that the PPAI molecules mixed with tBBAI became denser and may be beneficial for the charge transport process (Supplementary Fig. 8c, d). The above theoretical and experimental results suggest that the improved charge transport process could be thanks to the enhanced crystallization quality, ordered molecular orientation and improved molecular packing in BSPT layer, which is a novel interesting insight compared with other combined passivants literatures31,32,33.

Ultraviolet photoelectron spectroscopy (UPS) was utilized to confirm the energy band structure of perovskite with and without post-treatment (Supplementary Fig. 9a, b). After PPAI unary post-treatment, the work function (WF) of perovskite surface was uplifted from −4.67 eV to −4.23 eV (minus sign represents relative to vacuum energy level), while BSPT elevated the WF to an even higher value of −3.45 eV. The upshifted WF after post-treatment offered a more negative charged surface, which could induce a dipole with a built-in electrical field oriented from perovskite to passivation layer, accelerating the hole transport and blocking electron42. Besides, both PPAI unary post-treatment and BSPT provided an intermediate HOMO energy level between active layer and HTL, revealing a gradient alteration property favorable for hole extraction43. Moreover, BSPT perovskite surface held a much smaller HOMO level gap to Spiro-OMeTAD (0.13 eV) than PPAI unary post-treated perovskite (0.65 eV), which could ameliorate hole extraction to HTL and avoid hole accumulation at the interface44 (Fig. 1i and Supplementary Fig. 9c, d). We also employed Kelvin probe force microscopy (KPFM) to detect the surface potential distribution of perovskite films with distinct post-treatments (Supplementary Fig. 10a–c). BSPT sample owned a rather flat CPD distribution, while neat and PPAI unary post-treated sample possessed a rougher distribution with a clearer grain boundary. The evenly distributed CPD (Supplementary Fig. 10d) could probably induce a better physical contact and energy band alignment between perovskite and HTL, conducive for hole transfer and extraction. The higher average CPD values for BSPT and PPAI-treated perovskite film than pristine perovskite film were consistent with the upshifted work function revealed by UPS results45.

We carried out top-view scanning electron microscopy (SEM) and atomic force microscopy (AFM) to depict the surface morphology of neat perovskite film or perovskite film with PPAI unary post-treatment or perovskite film with BSPT. From SEM results (Supplementary Fig. 11), we found out that PPAI unary post-treatment could not entirely cover the perovskite surface, leaving some white dots and pinholes. The white dots may be attributed to the accumulation of PPAI at some local part, and the pinholes could be the lack of coverage at some local part due to the accumulation distribution mode of PPAI. Pinholes could be commonly found in unary organic halide salt post-treatment situations5. The pinholes could act as tunneling channels for charge carriers. In contrast, BSPT strategy led to a well-covered and uniform surface, which should provide a better post-treatment effect. Since the charge carrier transport ability has been effectively improved, the charge carriers could be transferred even without those pinholes observed in PPAI unary condition as tunneling channels. AFM results further depicted surface height fluctuation of samples and were mapped in a three-dimensional (3D) model (Fig. 2a–c). Although both showed smaller roughness than pristine perovskite (Ra = 22.7 nm), BSPT perovskite film could be even smoother (Ra = 9.76 nm) than PPAI unary post-treated perovskite film (Ra = 17.8 nm). We inferred that the BSPT layer should grow in a similar way as PEAI we reported before5, which could fill into the valleys of rough perovskite surface. The higher total concentration of BSPT layer than unary PPAI and tBBAI could lead to a more adequate filling to the valleys, which should be the reasons behind the substantial alteration in roughness following our BSPT method. We supposed that the tert-butyl group in tBBAI may also act as a framework to disperse the passivator more homogeneously. A more uniform and smoother surface could avoid the direct contact between perovskite film and electrode, generating less leakage current.

a–c 3D AFM mapping images of a pristine perovskite, b perovskite with PPAI unary post-treatment and c perovskite with BSPT, respectively. d Steady-state photoluminescence characterization of pristine perovskite, perovskite with PPAI unary post-treatment and perovskite with BSPT. e TRPL characterization of pristine perovskite, perovskite with PPAI unary post-treatment and perovskite with BSPT. f Transient reflection spectroscopy measurements of pristine perovskite, perovskite with PPAI unary post-treatment and perovskite with BSPT, respectively, using 700 nm pump light to excite the films. ΔR means change in reflection. g–i PL mapping patterns of g pristine perovskite film, h perovskite with PPAI unary post-treatment and i perovskite with BSPT. ssPL, TRPL, TRS and PL mapping characterization were carried out on glass/perovskite/passivation layer structure. a.u. arbitrary units.

Surface defects are prone to trap charge carriers, playing the role of nonradiative recombination center and holding negative impact on the charge transport process19. We used a 520 nm wavelength light to excite the film and observed a twofold steady-state photoluminescence (ssPL) intensity on the BSPT sample to PPAI unary post-treated sample, both showing obviously stronger signal than pristine perovskite (Fig. 2d). We also conducted the photoluminescence quantum yield (PLQY) tests and the variation trends of PLQY values were in accordance with the ssPL results (Supplementary Fig. 12). The results could provide evidence for the lowest surface defect density after BSPT and the non-radiation recombination loss was effectively reduced. The wavelength corresponding to the maximum PL intensity (λmax) showed negligible variation for all three samples, identical to the ignorable change on cutoff edges of ultraviolet-visible (UV-Vis) absorption spectra and Tauc plots (Supplementary Fig. 13), which was reasonable since the perovskite composition kept the same. For time-resolved PL (TRPL) testing, we operated a 375 nm laser to excite the samples and detected the PL intensity at λmax as a function of time after removing the laser. The TRPL lifetime of BSPT sample was calculated as 6.36 μs, nearly doubled the PPAI unary treated sample (3.46 μs) and even eight times longer than pristine perovskite film (0.81 μs) (Fig. 2e), which could be explained by fewer recombination centers after BSPT, demonstrating a better passivation function of the binary agents system than unary agent46,47,48. We further measured transient reflection spectroscopy (TRS) of perovskite films with different post-treatment (Fig. 2f). When using a pump light with a long wavelength (i.e., low photon energy, 700 nm) to excite the film, the BSPT perovskite film possessed an obviously slower surface carrier decay. Since the pump light of long wavelength creates small carrier concentration gradient and mainly reflects surface condition, it could be safely concluded that BSPT decreases the surface recombination rate of perovskite film49,50. BSPT strategy offered the passivation layer a better charge transport property, which allowed a higher total solution concentration than the unary passivation conditions, inducing a better passivation effect. To study the distribution of surface defects, we also mapped the PL intensity of the samples in a 15 × 15 μm area (Fig. 2g–i). The BSPT perovskite film possessed obviously more uniform and larger PL intensity, implying that the surface defects could be homogenously suppressed over the film. This could be attributed to the better coverage of passivation agents on perovskite through BSPT, which was in accordance with the AFM results.

Encouraged by the better crystallization quality, enhanced hole extraction ability and more effective passivation through BSPT of perovskite surface, we fabricated PSCs based on a device structure of FTO/SnO2/perovskite/passivation layer/Spiro-OMeTAD/Au (FTO, fluorine-doped tin oxide; Spiro-OMeTAD, 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene; Au, gold) (Fig. 1a and Supplementary Fig. 14). We set devices passivated by unary PPAI (10 mg/mL) as our control samples and devices with BSPT as target samples. To optimize the best tBBAI mixing concentration, we compared performances of devices with BSPT layers containing 10 mg/mL PPAI and different tBBAI concentrations (Supplementary Fig. 15 and Supplementary Table 1); 10 mg/mL tBBAI mixed with 10 mg/mL PPAI was confirmed to be the optimal BSPT concentration condition and all target samples were treated under such concentration.

To demonstrate the reproductivity of the devices, we each prepared 25 samples for control and target condition and plotted the PCE distributions as well as the parameters (VOC, JSC and FF) distributions for the two device categories (Fig. 3a). The PCE advancement after BSPT was primarily owe to the dramatic improvement of FF, which should be ascribed to the better hole extraction and transfer ability. An obvious decreased series resistance was also observed, implying a more fluent charge carrier transport channel after applying BSPT strategy (Supplementary Fig. 16), which is in accordance with previous result (Supplementary Fig. 5). The VOC was increased as well, which should be the result of suppressed charge recombination process at perovskite surface. Note that the VOC of control devices was already extremely high (~1.18 V) and fairly close to S-Q limit, the tiny growth on VOC of target devices (~0.01 V) was still inspiring. The JSC was virtually the same since the surface layer was unable to penetrate deep inside the perovskite bulk phase and influence the composition. The best target device we have fabricated showed a PCE of 26.75% tested in our own laboratory (Supplementary Fig. 17 and Supplementary Table 2). Such device showed negligible hysteresis between reverse and forward sweep (Fig. 3b and Supplementary Table 3) and exhibited steady power output of 26.1% under a bias of 1.04 V for 600 s (Fig. 3c). Compared with a typical control device (Supplementary Fig. 18 and Supplementary Table 4), VOC and FF of target device in both reverse and forward sweep were enhanced (Supplementary Table 3). The integrated current density calculated from the external quantum efficiency (EQE) data was in agreement with the JSC collected from the J-V measurement under solar simulator (Fig. 3d).

a Statistical distributions of VOC, JSC, FF and PCE values in a batch of 25 control devices and 25 target devices, respectively. b J-V curves of the champion target device under 1 Sun condition (100 mW/cm2). Reverse and forward sweep are plotted together. c Steady power output of the champion target device for 600 s with a bias of 1.04 V. d EQE and integrated JSC of the champion target device. e The ratio of our certified results to S-Q limit values51. VOC, JSC, FF and PCE are listed respectively. f MPP tracking of unencapsulated control and target devices under continuous 1 Sun illumination in a N2 atmosphere at a temperature of 50 ± 5 °C without active cooling. The initial PCE for control and target devices were 25.1% and 25.6% respectively.

We sent our best device to Japan Electrical Safety & Environment Technology Laboratories (JET) for accredited certification. A certified quasi-stabilized PCE of 26.0% with a VOC of 1.19 V, JSC of 26.00 mA cm−2 and FF of 84% was obtained (Supplementary Fig. 19a), corresponding to 83.4%, 95%, 94.1% and 93.2% of S-Q limit respectively51 (Fig. 3e). When comparing with other high-efficiency normal structure PSCs reported (certified PCE > 25%)6,7,8,9,13,52, we found that our device possessing the highest PCE/PCESQ value (Supplementary Fig. 20 and Supplementary Table 5), suggesting an extremely ideal charge carrier management during device operation process. Our result was collected both in the best research-cell efficiencies chart published by the National Renewable Energy Laboratory (NREL) in USA53 (Supplementary Fig. 19b) and solar cell efficiency tables published by Green et al.54 as the world record.

Operational stability is a crucial issue for the future commercialization of PSCs. We tracked the MPP output of the unencapsulated devices under continuous 1 Sun illumination (AM 1.5G, 100 mW cm−2) in a nitrogen-filled atmosphere at 50 ± 5 °C without active cooling (Fig. 3f). The target device could maintain 81% of its initial PCE after 450 h continuous output, at the same level with the high-efficient normal structure PSCs6,13, while the control device degraded to 78% of its initial PCE. We realize that our operational stability still lags behind commercial demand, which is still a challenge for normal structure with Spiro-OMeTAD as the hole transport layer. Developing a more stable HTL material to replace Spiro-OMeTAD could be a route to further promote device stability55,56. Besides, constructing interlayer to suppress ion migration process should also benefit the improvement of device stability. Replacing organic functional layer with more stable inorganic material could also be an effective method to enhance device stability. We also conducted thermal stability tests for target device (Supplementary Fig. 21). From the results, we could see that at the first 50 h, the PCE already degraded rapidly, which could be attributed to the formation of low-dimensional perovskite on the 3D perovskite surface5 (Supplementary Fig. 22). Therefore, a more thermally stable passivation agent should be explored in our future work. Humidity and ultraviolet irradiation stability tests for target device were also included (Supplementary Figs. 23, 24). Developing better encapsulation and effective ultraviolet filter technologies could further improve device stability.

We further conducted a series of characterizations based on the complete devices to understand the charge carrier dynamics and recombination mechanism more comprehensively. We first tested the device performances under different light intensity and plotted the VOC variation trends to calculate the ideal factors from the fitting curves57. BSPT device showed an ideal factor of 1.09 which was extraordinarily close to 1 and among the smallest as we know, indicating a considerably suppressed Shockley-Read-Hall (SRH) recombination process, while the control device showed a larger value of 1.26 (Fig. 4a). The JSC versus light intensity curves were also plotted under double logarithmic coordinate (Supplementary Fig. 25) and the linear relationship illustrated no obvious charge transport barrier in device13. We then applied Mott-Schottky method to measure the built-in voltage (Vbi) in device, which could reflect the charge separation and collection ability58. The capacitance-voltage (C-V) measurement was implemented and Vbi was acquired from the intercept with x-axis in C−2-V graph. The Vbi of target device was 1.04 V, larger than 1.00 V of control device, implying BSPT could be beneficial for charge separation and collection (Fig. 4b). To evaluate the trap density of states (tDOS), we measured the thermal admittance spectroscopy (TAS)44,59, and the results showed that the defect density was obviously reduced in the deep-trap region (above 0.4 eV)60 after BSPT, with the peak value decreasing from 1.84 × 1017 cm−3 eV−1 to 7.3 × 1016 cm−3 eV−1, which could be helpful for the charge carrier dynamics (Fig. 4c). The tDOS result offered quantitative evidence for the conclusion induced by PL result. Electrical impedance spectroscopy (EIS) results (Supplementary Fig. 26) also confirmed the reduction of SRH recombination rate after BSPT with a larger recombination resistance fitted by the equivalent circuit (inset graph)61.

a The VOC-light intensity relationship for control and target device. The ideal factors are presented beside the fitting curves. b Mott-Schottky curves of C-V measurement for control and target devices. The built-in voltages are presented beside the fitting curves. c TAS results for control and target devices. d I-V curves of control and target devices under dark environment. e TPC curves and fitting curves for control and target devices. The fitted lifetimes are presented beside the fitting curves. a.u. arbitrary units. f OCVD curves of control and target devices.

We also carried out the I-V measurements under dark environment (Fig. 4d), target device owned a reduced dark current compared with control device near zero voltage point, suggesting decreased electrical leakage channels. For target device, the lowest dark current was nearly located at the zero voltage point, declaring limited charge accumulation at the interfaces62. When applying higher forward voltage, the dark current of target device ascended more quickly, signifying better charge transport63. In order to study the device transient charge carrier dynamics, we conducted transient photocurrent (TPC) test and open-circuit voltage decay (OCVD) test. For TPC result, a faster photocurrent decay was observed on the target device, with a lifetime of merely 0.94 μs (Fig. 4e), which further proved the quick charge extraction process due to superior charge transfer capacity after BSPT64. In OCVD test, a slower VOC decay process indicated a more balanced charge carrier transport through BSPT strategy (Fig. 4f)65. A photogenerated charge extraction by linearly increasing voltage (Photo-CELIV) measurement was executed to evaluate the global charge carrier mobilities of device (Supplementary Fig. 27). A mobility value of 2.05 × 10−3 cm2 V−1 s−1 was obtained from the target device, which was larger than the control device with 1.90 × 10−3 cm2 V−1 s−1, indicating that the BSPT indeed facilitated the charge carrier transport in device66. Those device characterization results offered adequate evidence for a suppressed charge carrier recombination process as well as a more efficient charge carrier transport process after BSPT, which should be the main reasons for the improvement on both VOC and FF.

In general, we have proposed a BSPT strategy to improve the charge carrier transport property and defect suppression function of passivation layer. Specifically, a better crystallization quality and a more ordered molecular packing pattern of passivation layer were achieved with a more suitable energy band alignment, inducing a better hole extraction and transfer ability. Moreover, BSPT strategy further diminished surface trap-state density on the basis of PPAI unary passivation. As a result, a certified PCE as high as 26.0% was realized on our PSCs. The device could also maintain 81% of its original PCE after 450 h MPP tracking. Our work provides an effective method to passivate surface defects without sacrificing charge carrier transport ability, which should also be enlightening in the fields of other perovskite semiconductor optoelectronic devices67.

SnO2 colloid precursor (tin (IV) oxide, 15% in H2O colloidal dispersion) was purchased from Alfa Aesar. Dimethylformamide (DMF), dimethyl sulfoxide (DMSO), chlorobenzene (CB), isopropanol (IPA), lead iodide (PbI2), rubidium chloride (RbCl), bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI), acetonitrile and 4-tert-butylpyridine (tBP) were all purchased from Sigma Aldrich. Formamidinium iodide (FAI), methylammonium chloride (MACl), 4-tert-butylphenylmethylammonium iodide (tBuPMAI/tBBAI), phenylpropylammonium iodide (PPAI), Tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)- cobalt(III)Tris(bis(trifluoromethylsulfonyl)imide) (FK209), 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) were all purchased from Xi’an Yuri Solar Co., Ltd in China. 4-Isopropyl-4’-methyldiphenyliodonium Tetrakis(pentafluorophenyl) borate (TPFB) was purchased from TCI. Except for SnO2 colloid precursor stored in ambient air, all the materials are stored in the nitrogen-filled glove box to avoid the water and oxygen in air.

FTO glass was cleaned by sequentially washing with detergent, deionized water (DI), acetone and isopropanol (IPA). Before use, the FTO glass substrate was cleaned with ultraviolet ozone for 10 min. Then the substrate was spin-coated with a thin layer of SnO2 nanoparticle film (2.67%, diluted by DI) at 4000 r.p.m. for 30 s, and annealed in ambient air at 150 °C for 30 min. It is better to clean the SnO2 substrate with ultraviolet ozone for 10 min to improve the surface wetting. After that, the substrate was transferred into a nitrogen-filled glove box to finish the device fabrication process. A two-step method was applied to deposit the perovskite film. First, 1.5 M PbI2 doped with 5 mol% RbCl in DMF:DMSO (9:1) solvent was spin-coated onto SnO2 at 1500 r.p.m for 30 s, annealed at 70 °C for 1 min, and then cooled to room temperature. Second, a solution of FAI: MACl (90 mg: 9–18 mg in 1 ml IPA) was spin-coated onto the PbI2 film at 1800 r.p.m. for 30 s to form perovskite precursor film. Afterward, the perovskite precursor film was taken out from the nitrogen-filled glove box to ambient air for thermal annealing at 150 °C for 15 min in humidity conditions (30–40% relative humidity (RH)) to finally become α-phase FAPbI3 perovskite. It must be noted that humidity is very critical for achieving high crystallinity of perovskite films and high performance of devices. From our previous results, the RH should be controlled at around 30–40%, lower humidity will not promote the perovskite growth and high humidity could lead to perovskite decomposition. Humidifier or dehumidifier is usually used for keeping the RH at around 30–40% in the open ambient air environment. After perovskite formation, the samples were transferred back to the nitrogen-filled glove box for further processing. For control samples, 10 mg/mL PPAI was dissolved in IPA and spin-coated onto the perovskite surface at a spin rate of 5000 r.p.m. without any further annealing process. For target samples, 10 mg/mL PPAI added with 10 mg/mL tBBAI were dissolved in IPA together and spin-coated onto the perovskite surface at a spin rate of 5000 r.p.m. without any further annealing process to form BSPT layer. To optimize the tBBAI concentration, 5, 7.5, 15 mg/mL tBBAI was also tried within the solution. When depositing the HTL, 72.3 mg/mL Spiro-OMeTAD solution, which consisted of 35 μL Li-TFSI stock solution (260 mg Li-TFSI in 1 mL acetonitrile), 30 μL tBP and 3.59 μL FK209 stock solution (759.81 mg FK209 in 1 mL acetonitrile) in 1 mL chlorobenzene was spin-coated at 1500 r.p.m. for 30 s. The devices without electrode were put in a drying cabinet (25 °C, 1% RH) for overnight oxidation of Spiro-OMeTAD to enhance the conductivity. For the device thermal stability test, PTAA doped with TPFB was used to replace spiro-OMeTAD as the hole transport layer. The concentration of PTAA was 40 mg/mL and the weight ratio of PTAA/TPFB was 10:1.5. The PTAA was deposited on top of the perovskite layer at a spin rate of 2000 r.p.m. for 30 s. Finally, 80 nm of Au film was thermally evaporated as a counter electrode using a shadow mask. The device size areas were 0.108 cm2. When measuring J-V and EQE, a 0.07461 cm2 non-reflective mask was used to define the accurate active cell area.

The XRD patterns of the perovskite films were characterized on a D8 ADVANCE system (Bruker Nano Inc.) using Cu Kα radiation (λ = 1.5405 Å) as the X-ray source. For conventional XRD, a θ−2θ model was used. For the GIXRD measurement, the incident angle was 2.0°. The GIWAXS was performed at BL17B1 beamline of SSRF using the X-ray energy of 10 KeV. Two-dimensional patterns were acquired by a PLATUS 2M detector mounted vertically at a distance ~240 mm from the sample with a grazing-incidence angle of 0.2° or 0.4° and an exposure time of 20 s. XPS was performed on a Thermo Scientific ESCALab 250Xi using 200 W monochromated Al Kα (1486.6 eV) radiation. A 500 μm X-ray spot was used for XPS analysis. The base pressure in the analysis chamber was about 3 × 10−10 mbar. UPS was also carried out on a Thermo Scientific ESCALab 250Xi, with the HeI (21.22 eV) emission line employed for excitation. AFM and KPFM were performed using a Bruker Dimension Icon (Bruker Nano Inc.) and the scan rate was 0.5 Hz. KPFM measurements were performed in a tapping-contact mode in dark conditions. The SEM images were acquired using a field-emission scanning electron microscope (FEI NanoSEM650), in which an electron beam was accelerated at 500 V to 30 kV, enabling operation at a variety of currents. Absorption spectra were obtained using an ultraviolet-visible spectrometer (Cary 5000). Steady-state PL and TRPL spectra were measured by an FLS1000 spectrometer. During the steady-state PL intensity tests, we kept the slit bandwidth of the incident 520 nm light at 1.20 nm for all three conditions. In this way, we could excite the film sample at the same light power and make the steady-state PL intensity comparable between the samples. The incident 520 nm wavelength light was acquired from a 450 W xenon lamp and the light power density illuminated at the samples was around 3.5 mW/cm2. With a 0.05 cm2 area of light irradiation spot, we could calculate the light power of the 520 nm wavelength light is about 175 μW. For TRPL test, the samples were excited by a diode laser of 375 nm wavelength. For PLQY test, the samples were excited by a 368 nm light from a light-emitting diode and the PLQYs were recorded by a commercialized PLQY measurement system (LQE-50-PL) from Enlitech. For the PL mapping, a laser scanning confocal microscope equipped with a 532 nm pulse laser was used. The mapping area was set to be 15 × 15 μm. The laser source was set to 10 nW range on the sample for measurement. TRS measurements were conducted in a similar way with literature49. A Ti:sapphire laser amplifier (PHAROS-20W) can generate 1028 nm pulse. A branch of fundamental beam was transferred into an optical parametric amplifier (TP-OR-ORPHEUS-HP) to produce monochromatic pump pulses with different wavelengths. Another branch of beam was attenuated and focused into sapphire crystals to generate the broadband probe pulses in the visible regions. The time delay between the pump and probe pulses was controlled by a motorized translation stage. The reflected probe pulses were sent into the visible spectrometers.

The I-V characteristics of PPAI and BSPT layer were obtained using a Keithley 2400 Source Meter based on ITO/passivation layer/Au structure with the voltage step as 0.1 V. The J-V characteristics of the photovoltaic cells were obtained using a Keithley 2400 Source Meter under simulated 1 Sun AM 1.5G illumination (100 mW cm−2) with a solar simulator (Enlitech, SS-F5-3A) and the light intensity was calibrated by means of a KG-5 Si photodiode. The J-V measurements were carried out in ambient air at 25 °C. The devices were measured both in reverse scan (1.2 V → 0 V, step 0.02 V) and forward scan (0 V → 1.2 V, step 0.02 V). We sent the best devices to an accredited laboratory (JET, Japan) for certification. The operational stability tracking tests were conducted under a 1 Sun white light-emitting diode lamp illumination continuously in a nitrogen-filled glove box at 50 ± 5 °C without active cooling while the unencapsulated PSCs were masked and placed on a homemade sample holder. During measurements, a fixed bias voltage was applied on the devices to retain the PSCs working at MPP and reverse scanned J-V curves were recorded every 60 min by Keithley 2635B Source Meter. The dark I-V measurements were carried out in a black box and tested by Keithley 6482 Source Meter to detect the dark current more precisely. The EQE was measured using an Enlitech EQE measurement system (QE-R3018). TPC measurements were conducted on a commercial apparatus (Arkeo, Cicci Research) based on a high-speed waveform generator that drives high-speed light-emitting diodes (5000 K). EIS, C-V, photo-CELIV and OCVD tests were measured by an all-in-one characterization platform (Paios Fluxim AG) in air conditions without encapsulation. The device structures are the same as the J-V test. For EIS tests, the measurement frequency ranged from 10 Hz to 10 MHz at open-circuit condition under dark environment. C-V measurements were carried out at fixed frequency of 100 kHz under dark environment. The depletion widths W were calculated as 80.0 nm and 84.3 nm for control and target device, respectively, based on the slopes of the Mott-Schottky curves and were applied in the TAS analysis further together with the Vbi obtained from the intercepts. For photo-CELIV test, the delay time was set to 0 s, the light intensity was 100%, the light-pulse length was 5 ms and the sweep ramp rate was 100 V/ms. The mobility value μ could be calculated according to the following equation \(\mu=\frac{2{d}^{2}}{3A{{t}_{max }}^{2}}\times \frac{1}{1+0.36\frac{\triangle j}{{j}_{{disp}}}}\) , in which d represents the perovskite film thickness, A refers to the ramp rate, tmax is the time required to reach the current density peak, jdisp stands for the displacement current density and Δj is the difference between the peak current density and the displacement current density68. The TAS measurements were performed on an Agilent E4980A precision Lenz-Capacitor-Resistance (LCR) meter in the dark at 300 K. The d.c. bias was fixed at 0 V and the amplitude of the a.c. bias was 20 mV. The scanning range of the a.c. frequency (f) was 1–2000 kHz. The tDOS (Nt(Eω)) was calculated through the equation \({N}_{t}\left({E}_{\omega }\right)=-\frac{1}{q{k}_{B}T}\frac{\omega {dC}}{d\omega }\frac{{V}_{{bi}}}{W}\) , where q, kB, T, ω, C, W, Vbi, Nt and Eω are elementary charge, Boltzmann constant, temperature under Kelvin thermodynamic scale, angular frequency, specific capacitance, depletion width, build-in voltage, trap density of states and demarcation energy respectively59. The demarcation energy is defined based on the equation \({E}_{\omega }={k}_{B}T{{{\mathrm{ln}}}}(\frac{2{\beta }_{\rho }{N}_{V}}{\omega })\) , where βρ is capture coefficient of hole, NV is the effective density of states in the valence band. For FAPbI3 perovskite, βρ and NV are 10−8 cm3/s and 2.524 × 1019 cm−3, respectively, according to literature69. Before each measurement, the system was self-calibrated under open-circuit and short-circuit conditions to compensate for any undesired signal from the instrument.

To uncover the impact of halide-based organic salts on the packing, all-atom molecular dynamics (AA-MD) was performed using the GROMACS2021.2 package with the optimized potentials for liquid simulations-all atom (OPLS-AA) force field. The concentration used in the simulation (50 mg/mL) was higher than the concentration used in the experiment (10 mg/mL), due to the computational limitations of AA-MD. The first model was built by randomly inserting 200 PPAI and plenty of IPA molecules in cubic cells. For the BSPT condition, another model containing 200 PPAI, 182 tBBAI, and plenty of IPA molecules in 30 × 30 × 30 nm3 cells was also built. In both cases, we periodically removed 100 IPA solvent molecules per 300 ps to investigate the impact of the introduction of tBBAI molecules on the kinetic of the PPAI-tBBAI blended film formation. The LINCS algorithm was applied to constrain the covalent bonds with H-atoms70. The time step of the simulations was 1.0 fs. All the simulations were performed in periodic boundary conditions. The pressure and temperature were controlled with the Parrinello-Rahman barostat coupled in 1 atm and the V-rescale thermostat71,72. The cutoff of the nonbonded interactions was set to 12 Å. The particle mesh Ewald (PME) method was used to calculate the long-range electrostatic interactions73. The graphics and visualization analyses were processed by the Visual Molecular Dynamics (VMD) program74.

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All data generated or analyzed during this study are included in the published article and its Supplementary Information. Additional data are available from the corresponding author upon request.

Kojima, A., Teshima, K., Shirai, Y. & Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131, 6050–6051 (2009).

Article CAS PubMed Google Scholar

Kim, H. S. et al. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2, 7 (2012).

Lee, M. M., Teuscher, J., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643–647 (2012).

Article ADS CAS PubMed Google Scholar

Yang, W. S. et al. High-performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science 348, 1234–1237 (2015).

Article ADS CAS PubMed Google Scholar

Jiang, Q. et al. Surface passivation of perovskite film for efficient solar cells. Nat. Photonics 13, 460–466 (2019).

Article ADS CAS Google Scholar

Yoo, J. J. et al. Efficient perovskite solar cells via improved carrier management. Nature 590, 587–593 (2021).

Article ADS CAS PubMed Google Scholar

Min, H. et al. Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes. Nature 598, 444–450 (2021).

Article ADS CAS PubMed Google Scholar

Zhao, Y. et al. Inactive (PbI2)2RbCl stabilizes perovskite films for efficient solar cells. Science 377, 531–534 (2022).

Article ADS CAS PubMed Google Scholar

Park, J. et al. Controlled growth of perovskite layers with volatile alkylammonium chlorides. Nature 616, 724–730 (2023).

Article ADS CAS PubMed Google Scholar

Eperon, G. E. et al. Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells. Energy Environ. Sci. 7, 982–988 (2014).

Jeon, N. J. et al. Compositional engineering of perovskite materials for high-performance solar cells. Nature 517, 476–480 (2015).

Article ADS CAS PubMed Google Scholar

Saliba, M. et al. Incorporation of rubidium cations into perovskite solar cells improves photovoltaic performance. Science 354, 206–209 (2016).

Article ADS CAS PubMed Google Scholar

Jeong, J. et al. Pseudo-halide anion engineering for alpha-FAPbI3 perovskite solar cells. Nature 592, 381–385 (2021).

Article ADS CAS PubMed Google Scholar

Bi, D. et al. Polymer-templated nucleation and crystal growth of perovskite films for solar cells with efficiency greater than 21%. Nat. Energy 1, 16142 (2016).

Article ADS CAS Google Scholar

Hui, W. et al. Stabilizing black-phase formamidinium perovskite formation at room temperature and high humidity. Science 371, 1359–1364 (2021).

Article ADS CAS PubMed Google Scholar

Zhou, H. P. et al. Interface engineering of highly efficient perovskite solar cells. Science 345, 542–546 (2014).

Article ADS CAS PubMed Google Scholar

Zheng, X. et al. Defect passivation in hybrid perovskite solar cells using quaternary ammonium halide anions and cations. Nat. Energy 2, 17102 (2017).

Article ADS CAS Google Scholar

Lin, H. et al. Silicon heterojunction solar cells with up to 26.81% efficiency achieved by electrically optimized nanocrystalline-silicon hole contact layers. Nat. Energy 8, 789–799 (2023).

Article ADS CAS Google Scholar

Gao, F., Zhao, Y., Zhang, X. W. & You, J. B. Recent progresses on defect passivation toward efficient perovskite solar cells. Adv. Energy Mater. 10, 1902650 (2019).

Wang, Z. et al. Efficient ambient-air-stable solar cells with 2D-3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites. Nat. Energy 2, 17135 (2017).

Article ADS CAS Google Scholar

Chen, P. et al. In situ growth of 2D perovskite capping layer for stable and efficient perovskite solar cells. Adv. Funct. Mater. 28, 1706923 (2018).

Yang, S. et al. Stabilizing halide perovskite surfaces for solar cell operation with wide-bandgap lead oxysalts. Science 365, 473–478 (2019).

Article ADS CAS PubMed Google Scholar

Li, X. D. et al. Constructing heterojunctions by surface sulfidation for efficient inverted perovskite solar cells. Science 375, 434–437 (2022).

Article ADS CAS PubMed Google Scholar

Zuo, L. J. et al. Polymer-modified halide perovskite films for efficient and stable planar heterojunction solar cells. Sci. Adv. 3, 1700106 (2017).

Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p-n junction solar cells. J. Appl. Phys. 32, 510–519 (1961).

Article ADS CAS Google Scholar

Ma, C. & Park, N.-G. A realistic methodology for 30% efficient perovskite solar cells. Chem 6, 1254–1264 (2020).

Tan, F. R. et al. In situ back-contact passivation improves photovoltage and fill factor in perovskite solar cells. Adv. Mater. 31, 1807435 (2019).

Peng, J. et al. Nanoscale localized contacts for high fill factors in polymer-passivated perovskite solar cells. Science 371, 390–395 (2021).

Article ADS CAS PubMed Google Scholar

Zhu, H. et al. Tailored amphiphilic molecular mitigators for stable perovskite solar cells with 23.5% efficiency. Adv. Mater. 32, 1907757 (2020).

Ren, G. et al. Organic iodides in efficient and stable perovskite solar cells: strong surface passivation and interaction. Energy Environ. Sci. 16, 565–573 (2023).

Liu, Z. et al. Grain regrowth and bifacial passivation for high-efficiency wide-bandgap perovskite solar cells. Adv. Energy Mater. 13, 2203230 (2022).

Liu, Z. et al. Reducing perovskite/C60 interface losses via sequential interface engineering for efficient perovskite/silicon tandem solar cell. Adv. Mater. 36, e2308370 (2024).

Liu, C. et al. Bimolecularly passivated interface enables efficient and stable inverted perovskite solar cells. Science 382, 810–815 (2023).

Article ADS CAS PubMed Google Scholar

Ling, X. et al. Combined precursor engineering and grain anchoring leading to MA-free, phase-pure, and stable alpha-formamidinium lead iodide perovskites for efficient solar cells. Angew. Chem. Int. Ed. Engl. 60, 27299–27306 (2021).

Article CAS PubMed Google Scholar

Qin, M., Chan, P. F. & Lu, X. A systematic review of metal halide perovskite crystallization and film formation mechanism unveiled by in situ GIWAXS. Adv. Mater. 33, 2105290 (2021).

Tsai, H. et al. High-efficiency two-dimensional Ruddlesden-Popper perovskite solar cells. Nature 536, 312–316 (2016).

Article ADS CAS PubMed Google Scholar

Zhou, N. et al. Exploration of crystallization kinetics in quasi two-dimensional perovskite and high performance solar cells. J. Am. Chem. Soc. 140, 459–465 (2017).

Choi, Y. et al. A vertically oriented two-dimensional Ruddlesden-Popper phase perovskite passivation layer for efficient and stable inverted perovskite solar cells. Energy Environ. Sci. 15, 3369–3378 (2022).

Jorgensen, W. L. & Tiradorives, J. The OPLS potential functions for proteins. Energy minimizations for crystals of cyclic peptides and crambin. J. Am. Chem. Soc. 110, 1657–1666 (1988).

Article CAS PubMed Google Scholar

Abraham, M. J. et al. GROMACS: high performance molecular simulations through multi-level parallelism from laptops to supercomputers. SoftwareX 1–2, 19–25 (2015).

Dahlgren, M. K., Schyman, P., Tirado-Rives, J. & Jorgensen, W. L. Characterization of biaryl torsional energetics and its treatment in OPLS all-atom force fields. J. Chem. Inf. Model. 53, 1191–1199 (2013).

Article CAS PubMed PubMed Central Google Scholar

Liang, L., Luo, H., Hu, J., Li, H. & Gao, P. Efficient perovskite solar cells by reducing interface‐mediated recombination: a bulky amine approach. Adv. Energy Mater. 10, 2000197 (2020).

Chu, X. et al. Surface in situ reconstruction of inorganic perovskite films enabling long carrier lifetimes and solar cells with 21% efficiency. Nat. Energy 8, 372–380 (2023).

Article ADS CAS Google Scholar

Shen, L. et al. Ion diffusion management enables all-interface defect passivation of perovskite solar cells. Adv. Mater. 35, e2301624 (2023).

You, S. et al. Bifunctional hole-shuttle molecule for improved interfacial energy level alignment and defect passivation in perovskite solar cells. Nat. Energy 8, 515–525 (2023).

Article ADS CAS Google Scholar

Zhang, Y. et al. Depth-dependent defect manipulation in perovskites for high-performance solar cells. Energy Environ. Sci. 14, 6526–6535 (2021).

Wu, P. et al. Mixed cations enabled combined bulk and interfacial passivation for efficient and stable perovskite solar cells. Nanomicro. Lett. 15, 114 (2023).

ADS CAS PubMed PubMed Central Google Scholar

Suo, J. et al. Surface reconstruction engineering with synergistic effect of mixed‐salt passivation treatment toward efficient and stable perovskite solar cells. Adv. Funct. Mater. 31, 2102902 (2021).

Deng, J. et al. Molecular bridge assisted bifacial defect healing enables low energy loss for efficient and stable perovskite solar cells. Adv. Funct. Mater. 32, 2209516 (2022).

Jiang, Q. et al. Surface reaction for efficient and stable inverted perovskite solar cells. Nature 611, 278–283 (2022).

Article ADS CAS PubMed Google Scholar

Rühle, S. Tabulated values of the Shockley-Queisser limit for single junction solar cells. Sol. Energy 130, 139–147 (2016).

Kim, M. et al. Conformal quantum dot-SnO2 layers as electron transporters for efficient perovskite solar cells. Science 375, 302–306 (2022).

Article ADS CAS PubMed Google Scholar

National Renewable Energy Laboratory, U.S. Department of Energy. Interactive Best Research-Cell Efficiency Chart. https://www.nrel.gov/pv/interactive-cell-efficiency.html (USA, 2023).

Green, M. A. et al. Solar cell efficiency tables (version 62). Prog. Photovoltaics 31, 651–663 (2023).

Wang, T. et al. Transporting holes stably under iodide invasion in efficient perovskite solar cells. Science 377, 1227–1231 (2022).

Article ADS CAS PubMed Google Scholar

Jeong, M. J., Yeom, K. M., Kim, S. J., Jung, E. H. & Noh, J. H. Spontaneous interface engineering for dopant-free poly(3-hexylthiophene) perovskite solar cells with efficiency over 24%. Energy Environ. Sci. 14, 2419–2428 (2021).

Yang, D. et al. Surface optimization to eliminate hysteresis for record efficiency planar perovskite solar cells. Energy Environ. Sci. 9, 3071–3078 (2016).

Almora, O., Aranda, C., Mas-Marzá, E. & Garcia-Belmonte, G. On Mott-Schottky analysis interpretation of capacitance measurements in organometallic perovskite solar cells. Appl. Phys. Lett. 109, 173903 (2016).

Ni, Z. Y. et al. Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells. Science 367, 1352–1358 (2020).

Article ADS CAS PubMed Google Scholar

Luo, Y. et al. Dissolved-Cl2 triggered redox reaction enables high-performance perovskite solar cells. Nat. Commun. 14, 3738 (2023).

Article ADS CAS PubMed PubMed Central Google Scholar

Wu, J. et al. Regioselective multisite atomic-chlorine passivation enables efficient and stable perovskite solar cells. J. Am. Chem. Soc. 145, 5872–5879 (2023).

Article CAS PubMed Google Scholar

Sadollahkhani, A. et al. Energetic barriers to interfacial charge transfer and ion movement in perovskite solar cells. ChemPhysChem 18, 3047–3055 (2017).

Article CAS PubMed Google Scholar

Jiang, Q. et al. Enhanced electron extraction using SnO2 for high-efficiency planar-structure HC(NH2)2PbI3-based perovskite solar cells. Nat. Energy 2, 1–7 (2017).

Wang, S. et al. Over 24% efficient MA-free CsxFA1−xPbX3 perovskite solar cells. Joule 6, 1344–1356 (2022).

Zhang, Y. et al. 24.11% high performance perovskite solar cells by dual interfacial carrier mobility enhancement and charge-carrier transport balance. Adv. Energy Mater. 12, 2201269 (2022).

Article MathSciNet CAS Google Scholar

Im, J. H., Jang, I. H., Pellet, N., Grätzel, M. & Park, N. G. Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells. Nat. Nanotechnol. 9, 927–932 (2014).

Article ADS CAS PubMed Google Scholar

Khan, R., Shi, G., Chen, W., Xiao, Z. & Ding, L. Interface engineering yields efficient perovskite light-emitting diodes. J. Semicond. 44, 120501 (2023).

Stephen, M., Genevičius, K., Juška, G., Arlauskas, K. & Hiorns, R. C. Charge transport and its characterization using photo-CELIV in bulk heterojunction solar cells. Polym. Int. 66, 13–25 (2017).

Wang, M. H. et al. Synergetic co-modulation of crystallization and co-passivation of defects for FAPbI3 perovskite solar cells. Adv. Funct. Mater. 32, 2108567 (2022).

Hess, B., Bekker, H., Berendsen, H. J. C. & Fraaije, J. LINCS: a linear constraint solver for molecular simulations. J. Comput. Chem. 18, 1463–1472 (1997).

Parrinello, M. & Rahman, A. Polymorphic transitions in single crystals: a new molecular dynamics method. J. Appl. Phys. 52, 7182–7190 (1981).

Article ADS CAS Google Scholar

Bussi, G., Donadio, D. & Parrinello, M. Canonical sampling through velocity rescaling. J. Chem. Phys. 126, 014101 (2007).

Article ADS PubMed Google Scholar

Essmann, U. et al. A smooth particle mesh Ewald method. J. Chem. Phys. 103, 8577–8593 (1995).

Article ADS CAS Google Scholar

Humphrey, W., Dalke, A. & Schulten, K. VMD: visual molecular dynamics. J. Mol. Graphics 14, 33–38 (1996).

Ma, F. et al. Efficient perovskite solar cells with iodine-doped spiro-OMeTAD hole transport layer via fast oxidation. Sol. RRL 7, 2300042 (2023).

This work was supported by the National Key Research and Development Program of China (grant number: 2020YFB1506400) and the National Natural Science Foundation of China (grant number: 61925405). We thank Y. Li from Soochow University for helping with TAS measurements, C. Yi from Tsinghua University for helping with TPC characterization and L. Meng from the Institute of Chemistry, Chinese Academy of Sciences for helping with Photo-CELIV measurement.

Laboratory of Semiconductor Physics, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, P. R. China

Zihan Qu, Yang Zhao, Fei Ma, Haitao Zhou, Xinbo Chu, Qi Jiang, Xingwang Zhang & Jingbi You

Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, P. R. China

Zihan Qu, Yang Zhao, Fei Ma, Haitao Zhou, Xinbo Chu, Qi Jiang, Xingwang Zhang & Jingbi You

School of Physics, Liaoning University, 110036, Shenyang, Liaoning, P. R. China

Department of Chemistry, City University of Hong Kong, 999077, Kowloon, Hong Kong, P. R. China

Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 215123, Suzhou, Jiangsu, PR China

Le Mei & Xian-Kai Chen

Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, 215123, Suzhou, Jiangsu, P. R. China

Le Mei & Xian-Kai Chen

Shanghai Synchrotron Radiation Facility (SSRF), Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210, Shanghai, P. R. China

School of Microelectronics, Fudan University, 200433, Shanghai, P. R. China

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J.Y. directed and supervised the project. J.Y. and Z.Q. conceived the idea and designed the experiment. Y.Z. contributed to device fabrication, characterization and certification. L.M. and X.-K.C. conducted the all-atom molecular dynamics simulation. Y.Y. conducted the GIWAXS characterizations. F.M., H.Z., X.C., Q.J. and X.Z. were involved in data analysis. Z.Q. and J.Y. co-wrote the manuscript. All authors contributed to the discussions and finalization of the manuscript.

The authors declare no competing interests.

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Qu, Z., Zhao, Y., Ma, F. et al. Enhanced charge carrier transport and defects mitigation of passivation layer for efficient perovskite solar cells. Nat Commun 15, 8620 (2024). https://doi.org/10.1038/s41467-024-52925-y

DOI: https://doi.org/10.1038/s41467-024-52925-y

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Enhanced charge carrier transport and defects mitigation of passivation layer for efficient perovskite solar cells | Nature Communications