Composition pinning growth for efficient and stable all-inorganic Pb-Sn perovskite solar cells

Abstract

All-inorganic Pb-Sn perovskites offer near-optimal bandgaps for photovoltaics but suffer from compositional inhomogeneity and limited operational stability, particularly in large-area devices. Here, we demonstrate that the film formation pathway plays a decisive role in governing the optoelectronic properties and device performance of all-inorganic CsPb_0.5Sn_0.5I₃ perovskite solar cells (PSCs). By employing a composition pinning growth (CPG) strategy, the formation of segregation-prone crystallization states is suppressed, leading to reduced surface Sn enrichment and Sn oxidation, lower defect density, and more favorable charge-carrier dynamics. As a result, CPG-based devices achieve power conversion efficiencies (PCEs) of 19.37% at the unit-cell level, among the highest of reported all-inorganic Pb-Sn PSCs, and 17.03% for 64 cm² aperture area modules and enhanced operational stability, retaining approximately 87% of the initial efficiency after 1000 h of continuous operation at 85°C and 85% relative humidity. This work establishes growth-pathway engineering as a scalable and effective strategy for achieving high-efficiency, stable all-inorganic CsPb_0.5Sn_0.5I₃ perovskite photovoltaics.

Keywords

all-inorganic perovskite / composition pinning growth / lead-tin perovskite / perovskite solar cells

References

[1] Shockley W, Queisser HJ. Detailed balance limit of efficiency of p-n junction solar cells. J Appl Phys. 1961; 32(3): 510-519.

[2] Liao W, Zhao D, Yu Y, et al. Fabrication of efficient low-bandgap perovskite solar cells by combining formamidinium tin iodide with methylammonium lead iodide. J Am Chem Soc. 2016; 138(38): 12360-12363.

[3] Polman A, Knight M, Garnett EC, Ehrler B, Sinke WC. Photovoltaic materials: present efficiencies and future challenges. Science. 2016; 352(6283):aad4424.

[4] Zong Y, Zhou Z, Chen M, Padture NP, Zhou Y. Lewis-adduct mediated grain-boundary functionalization for efficient ideal-bandgap perovskite solar cells with superior stability. Adv Energy Mater. 2018; 8(27):1800997.

[5] Hu M, Chen M, Guo P, et al. Sub-1.4ev bandgap inorganic perovskite solar cells with long-term stability. Nat Commun. 2020; 11(1): 151.

[6] Li C, Song Z, Chen C, et al. Low-bandgap mixed tin-lead iodide perovskites with reduced methylammonium for simultaneous enhancement of solar cell efficiency and stability. Nat Energy. 2020; 5(10): 768-776.

[7] Yang F, Zhu K. Advances in mixed tin-lead narrow-bandgap perovskites for single-junction and all-perovskite tandem solar cells. Adv Mater. 2024; 36(31):2314341.

[8] Pan H, Bai Y, Sun K, et al. Decoupling photothermal-mechanical degradation through lattice-stabilizing networks in Sn-Pb perovskites and all-perovskite tandem solar cells. Nat Commun. 2025; 16(1): 9221.

[9] Dong H, Ran C, Gao W, Li M, Xia Y, Huang W. Metal halide perovskite for next-generation optoelectronics: progresses and prospects. eLight. 2023; 3(1): 3.

[10] Zheng K, Ge J, Liu C, et al. Improved phase stability of CsPBi₂Br perovskite by released microstrain toward highly efficient and stable solar cells. InfoMat. 2021; 3(12): 1431-1444.

[11] Kulbak M, Gupta S, Kedem N, et al. Cesium enhances long-term stability of lead bromide perovskite-based solar cells. J Phys Chem Lett. 2016; 7(1): 167-172.

[12] Sutton RJ, Eperon GE, Miranda L, et al. Bandgap-tunable cesium lead halide perovskites with high thermal stability for efficient solar cells. Adv Energy Mater. 2016; 6(8):1502458.

[13] Zhou W, Zhao Y, Zhou X, et al. Light-independent ionic transport in inorganic perovskite and ultrastable Cs-based perovskite solar cells. J Phys Chem Lett. 2017; 8(17): 4122-4128.

[14] Li N, Zhu Z, Li J, Jen AK-Y, Wang L. Inorganic CsPb_1-xSn_xIBr₂ for efficient wide-bandgap perovskite solar cells. Adv Energy Mater. 2018; 8:1800525.

[15] Zhang W, Liu H, Qu Y, et al. B-site co-doping coupled with additive passivation pushes the efficiency of Pb-Sn mixed inorganic perovskite solar cells to over 17%. Adv Mater. 2024; 36:2309193.

[16] Duan C, Hu M, Zhu Q, et al. Tuning the crystallization and photothermal aging chemistry of CsPb_0.4Sn_0.6I₃ for inorganic perovskite tandem photovoltaics. Angew Chem Int Ed. 2025; 64(29):e202507761.

[17] Duan C, Zhang K, Peng Z, et al. Durable all-inorganic perovskite tandem photovoltaics. Nature. 2025; 637(8048): 1111-1117.

[18] Zhang W, Liu H, Huang T, et al. Oriented molecular dipole-enabled modulation of NiO_x/perovskite interface for Pb-Sn mixed inorganic perovskite solar cells. Adv Mater. 2025; 37(8):2414125.

[19] Bai Y, Meng Y, Yang M, et al. Lattice stabilization and strain homogenization in Sn-Pb bottom subcells enable stable all-perovskite tandems solar cells. Nat Commun. 2025; 16(1): 7344.

[20] Jia X, Yang D, Zheng D, et al. The progress and challenges of tin-lead alloyed perovskites: toward the development of large-scale all-perovskite tandem solar cells. Chem. 2025; 11(1):102384.

[21] Lin R, Gao H, Lou J, et al. All-perovskite tandem solar cells with dipolar passivation. Nature. 2025; 648(8094): 600-606.

[22] Xiao K, Lin Y-H, Zhang M, et al. Scalable processing for realizing 21.7%-efficient all-perovskite tandem solar modules. Science. 2022; 376(6594): 762-767.

[23] Li C, Chen L, Jiang F, et al. Diamine chelates for increased stability in mixed Sn-Pb and all-perovskite tandem solar cells. Nat Energy. 2024; 9(11): 1388-1396.

[24] Tong J, Jiang Q, Ferguson AJ, et al. Carrier control in Sn-Pb perovskites via 2D cation engineering for all-perovskite tandem solar cells with improved efficiency and stability. Nat Energy. 2022; 7(7): 642-651.

[25] Yang X, Ma T, Hu H, et al. Understanding and manipulating the crystallization of Sn-Pb perovskites for efficient all-perovskite tandem solar cells. Nat Photonics. 2025; 19(4): 426-433.

[26] Zhao D, Chen C, Wang C, et al. Efficient two-terminal all-perovskite tandem solar cells enabled by high-quality low-bandgap absorber layers. Nat Energy. 2018; 3(12): 1093-1100.

[27] Tong J, Song Z, Kim DH, et al. Carrier lifetimes of >1 μs in Sn-Pb perovskites enable efficient all-perovskite tandem solar cells. Science. 2019; 364(6439): 475-479.

[28] Gunasekaran RK, Jung J, Yang SW, et al. High-throughput compositional mapping of triple-cation tin–lead perovskites for high-efficiency solar cells. InfoMat. 2023; 5(4):e12393.

[29] Chung I, Song J-H, Im J, et al. CsSnI₃: semiconductor or metal? High electrical conductivity and strong near-infrared photoluminescence from a single material. High hole mobility and phase-transitions. J Am Chem Soc. 2012; 134(20): 8579-8587.

[30] Xu P, Chen S, Xiang H-J, Gong X-G, Wei S-H. Influence of defects and synthesis conditions on the photovoltaic performance of perovskite semiconductor CsSnI₃. Chem Mater. 2014; 26(20): 6068-6072.

[31] Ke W, Kanatzidis MG. Prospects for low-toxicity lead-free perovskite solar cells. Nat Commun. 2019; 10(1): 965.

[32] Li S, Yang X, Cheng S, et al. Solvent engineering enables tin-lead perovskite films with long carrier diffusion lengths and reduced tin segregation. Nat Commun. 2025; 16(1): 8072.

[33] Cho S, Pandey P, Bì H, et al. Record power conversion efficiency in wide bandgap lead-free perovskite solar cells enabled by a natural vitamin h (biotin) complex. InfoMat. 2025; 7(10):e70052.

[34] Cao F, Tian W, Wang M, Wang M, Li L. Stability enhancement of lead-free CsSnI₃ perovskite photodetector with reductive ascorbic acid additive. InfoMat. 2020; 2(3): 577-584.

[35] Gao W, Yang F, Wang Z, Lan Y, Nie R, Ran C. Interface matters: boosting efficient Pb-Sn perovskite solar cells for all-perovskite tandem photovoltaics. Adv Mater. 2026; 38(9):e21789.

[36] Wang X, Yang Z, Yang P, et al. Balancing disparate crystallization kinetics in Sn-Pb perovskites using a sulfaguanidine additive for high-performance solar cells. J Phys Chem Lett. 2025; 16(28): 7236-7241.

[37] Liu H, Wang L, Li R, et al. Modulated crystallization and reduced v_oc deficit of mixed lead-tin perovskite solar cells with antioxidant caffeic acid. ACS Energy Lett. 2021; 6(8): 2907-2916.

[38] Zhou J, Fu S, Zhou S, et al. Mixed tin-lead perovskites with balanced crystallization and oxidation barrier for all-perovskite tandem solar cells. Nat Commun. 2024; 15(1): 2324.

[39] Panda DP, Issaoui R, Iqbal Z, et al. Dmso-free tin halide perovskites for indoor photovoltaics. ACS Energy Lett. 2025; 10(8): 3789-3798.

[40] Zhang Z, Liang J, Wang J, et al. Dmso-free solvent strategy for stable and efficient methylammonium-free Sn-Pb alloyed perovskite solar cells. Adv Energy Mater. 2023; 13(17):2300181.

[41] Hu M, Zhang Y, Gong J, et al. Surface Sn(IV) hydrolysis improves inorganic Sn-Pb perovskite solar cells. ACS Energy Lett. 2023; 8(2): 1035-1041.

[42] Chang S, Zhang Z, Su Y, et al. Synergetic effect of non-invasive posttreatment agents enables highly efficient and stable all-inorganic Sn-Pb perovskite solar cells. Chem Eng J. 2024; 500:156707.

[43] Liang J, Zhao P, Wang C, et al. CsPb_0.9Sn_0.1Ibr₂ based all-inorganic perovskite solar cells with exceptional efficiency and stability. J Am Chem Soc. 2017; 139(40): 14009-14012.

[44] Lee S, Moon J, Ryu J, et al. Inorganic narrow bandgap cspb_0.4sn_0.6i_2.4br_0.6 perovskite solar cells with exceptional efficiency. Nano Energy. 2020; 77:105309.

[45] Yang Z, Zhang X, Yang W, Eperon GE, Ginger DS. Tin–lead alloying for efficient and stable all-inorganic perovskite solar cells. Chem Mater. 2020; 32(7): 2782-2794.

[46] Chen G, Li P, Xue T, et al. Design of low bandgap CsPb_1-xSn_xI₂Br perovskite solar cells with excellent phase stability. Small. 2021; 17(30):2101380.

[47] Huang S, Kuan C-H, Tian Y, et al. Efficient ideal-bandgap tin-lead alloyed inorganic perovskite solar cells enabled by structural dimension engineering. Adv Opt Mater. 2022; 10(20):2200891.

[48] Sun Q, Zhang Z, Zhang T, et al. Integrated 4-terminal all-inorganic perovskite tandem solar cell with open-circuit voltage exceeding 2.1 v for water splitting. ACS Energy Lett. 2022; 7(12): 4215-4223.

[49] Zhang W, Liu H, Qi X, et al. Oxalate pushes efficiency of CsPb_0.7Sn_0.3IBr₂ based all-inorganic perovskite solar cells to over 14%. Adv Sci. 2022; 9(11):2106054.

[50] Wen Q, Duan C, Zou F, et al. All-inorganic CsPb_1-xSn_xI₂Br perovskites mediated by dicyandiamide additive for efficient 4-terminal tandem solar cell. Chem Eng J. 2023; 452:139697.

[51] Zhang Z, Dai L, Zhang M, et al. Surface modification in CsPb_0.5Sn_0.5I₂Br inorganic perovskite solar cells: effects of bifunctional dipolar molecules on photovoltaic performance. ACS Appl Mater Interfaces. 2023; 15(30): 36594-36601.

[52] Zhang T, Qian F, Chen H, et al. Critical role of post-treatment induced surface reconstruction for high performance inorganic tin-lead perovskite solar cells. Chem Eng J. 2024; 479:147554.

[53] Li H, Feng W, Wei J, et al. Synchronizing crystallization enables thermally stable all-fa Pb-Sn perovskites for printable ma-free all-perovskite tandem solar cells. Energ Environ Sci. 2026; 19(4): 1296-1305.

[54] Zhang Y, Li C, Zhao H, et al. Synchronized crystallization in tin-lead perovskite solar cells. Nat Commun. 2024; 15(1): 6887.

[55] Cullity BD, Stock SR. Elements of x-Ray Diffraction. Prentice Hall; 2001.

[56] Heo JH, Lee MH, Jang MH, Im SH. Highly efficient CH₃NH₃PbI_3-xCl_x mixed halide perovskite solar cells prepared by re-dissolution and crystal grain growth via spray coating. J Mater Chem A. 2016; 4(45): 17636-17642.

[57] Kim SS, Heo JH, Im SH. Wetting-induced formation of void-free metal halide perovskite films by green ultrasonic spray coating for large-area mesoscopic perovskite solar cells. RSC Adv. 2020; 10(56): 33651-33661.

[58] Heo JH, Zhang F, Xiao C, et al. Efficient and stable graded CsPbI_3-xBr_x perovskite solar cells and submodules by orthogonal processable spray coating. Joule. 2021; 5(2): 481-494.

[59] Park SW, Heo JH, Lee HJ, Kim H, Im SH, Hong KH. Compositional design for high-efficiency all-inorganic tin halide perovskite solar cells. ACS Energy Lett. 2023; 8(12): 5061-5069.

[60] Heo JH, Hong SY, Park JK, Lee HJ, Zhang F, Im SH. Chemical oxidization of PTAA enables stable slot-die-coated perovskite solar modules. Joule. 2025; 9(4):101850.

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