Lightweight flexible perovskite solar cells are promising for building integrated photovoltaics, wearable electronics, portable energy systems and aerospace applications. However, their highest certified efficiency of 19.9% lags behind their rigid counterparts (highest 25.7%), mainly due to defective interfaces at charge-selective contacts with perovskites on top. Here we use a mixture of two hole-selective molecules based on carbazole cores and phosphonic acid anchoring groups to form a self-assembled monolayer and bridge perovskite with a low temperature-processed NiO nanocrystal film. The hole-selective contact mitigates interfacial recombination and facilitates hole extraction. We show flexible all-perovskite tandem solar cells with an efficiency of 24.7% (certified 24.4%), outperforming all types of flexible thin-film solar cell. We also report 23.5% efficiency for larger device areas of 1.05 cm2. The molecule-bridged interfaces enable significant bending durability of flexible all-perovskite tandem solar cells that retain their initial performance after 10,000 cycles of bending at a radius of 15 mm.
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Yang, D., Yang, R., Priya, S. & Liu, S. Recent advances in flexible perovskite solar cells: fabrication and applications. Angew. Chem. Int. Ed. 58, 4466–4483 (2019).
Tavakoli, M. M. et al. Highly efficient flexible perovskite solar cells with antireflection and self-cleaning nanostructures. ACS Nano 9, 10287–10295 (2015).
Ling, H., Liu, S., Zheng, Z. & Yan, F. Organic flexible electronics. Small Methods 2, 1800070 (2018).
Hashemi, S. A., Ramakrishna, S. & Aberle, A. G. Recent progress in flexible-wearable solar cells for self-powered electronic devices. Energy Environ. Sci. 13, 685–743 (2020).
Long, J. et al. Flexible perovskite solar cells: device design and perspective. Flex. Print. Electron. 5, 013002 (2020).
Heo, J. H., Lee, D. S., Shin, D. H. & Im, S. H. Recent advancements in and perspectives on flexible hybrid perovskite solar cells. J. Mater. Chem. A 7, 888–900 (2019).
Mujahid, M., Chen, C., Hu, W., Wang, Z.-K. & Duan, Y. Progress of high-throughput and low-cost flexible perovskite solar cells. Sol. RRL 4, 1900556 (2020).
Kumar, M. H. et al. Flexible, low-temperature, solution processed ZnO-based perovskite solid state solar cells. Chem. Commun. 49, 11089–11091 (2013).
Chung, J. et al. Record-efficiency flexible perovskite solar cell and module enabled by a porous-planar structure as an electron transport layer. Energy Environ. Sci. 13, 4854–4861 (2020).
Yang, L. et al. Artemisinin-passivated mixed-cation perovskite films for durable flexible perovskite solar cells with over 21% efficiency. J. Mater. Chem. A 9, 1574–1582 (2021).
Wu, S. et al. Low-bandgap organic bulk-heterojunction enabled efficient and flexible perovskite solar cells. Adv. Mater. 33, 2105539 (2021).
Best research-cell efficiency chart. NREL https://www.nrel.gov/pv/cell-efficiency.html (2022).
Zardetto, V., Brown, T. M., Reale, A. & Di Carlo, A. Substrates for flexible electronics: a practical investigation on the electrical, film flexibility, optical, temperature, and solvent resistance properties. J. Polym. Sci. B 49, 638–648 (2011).
Zeng, P., Deng, W. & Liu, M. Recent advances of device components toward efficient flexible perovskite solar cells. Sol. RRL 4, 1900485 (2020).
Liu, D. & Kelly, T. L. Perovskite solar cells with a planar heterojunction structure prepared using room-temperature solution processing techniques. Nat. Photonics 8, 133–138 (2014).
Shin, S. S. et al. High-performance flexible perovskite solar cells exploiting Zn2SnO4 prepared in solution below 100 °C. Nat. Commun. 6, 7410 (2015).
Dong, Q. et al. Improved SnO2 electron transport layers solution-deposited at near room temperature for rigid or flexible perovskite solar cells with high efficiencies. Adv. Energy Mater. 9, 1900834 (2019).
Hu, X. et al. Wearable large-scale perovskite solar-power source via nanocellular scaffold. Adv. Mater. 29, 1703236 (2017).
Bi, C., Chen, B., Wei, H., DeLuca, S. & Huang, J. Efficient flexible solar cell based on composition-tailored hybrid perovskite. Adv. Mater. 29, 1605900 (2017).
Yin, X. et al. Highly efficient flexible perovskite solar cells using solution-derived NiOx hole contacts. ACS Nano 10, 3630–3636 (2016).
Ma, F. et al. Nickel oxide for inverted structure perovskite solar cells. J. Energy Chem. 52, 393–411 (2020).
Yin, X., Guo, Y., Xie, H., Que, W. & Kong, L. B. Nickel oxide as efficient hole transport materials for perovskite solar cells. Sol. RRL 3, 1900001 (2019).
Wang, Q. et al. Effects of self-assembled monolayer modification of nickel oxide nanoparticles layer on the performance and application of inverted perovskite solar cells. ChemSusChem 10, 3794–3803 (2017).
Cheng, Y. et al. Impact of surface dipole in NiOx on the crystallization and photovoltaic performance of organometal halide perovskite solar cells. Nano Energy 61, 496–504 (2019).
Ru, P. et al. High electron affinity enables fast hole extraction for efficient flexible inverted perovskite solar cells. Adv. Energy Mater. 10, 1903487 (2020).
Du, Y. et al. Polymeric surface modification of NiOx-based inverted planar perovskite solar cells with enhanced performance. ACS Sustain. Chem. Eng. 6, 16806–16812 (2018).
Zhang, S. et al. Printable and homogeneous NiOx hole transport layers prepared by a polymer-network gel method for large-area and flexible perovskite solar cells. Adv. Funct. Mater. 31, 2106495 (2021).
Boyd, C. C. et al. Overcoming redox reactions at perovskite–nickel oxide interfaces to boost voltages in perovskite solar cells. Joule 4, 1759–1775 (2020).
Xiao, K. et al. All-perovskite tandem solar cells with 24.2% certified efficiency and area over 1 cm2 using surface-anchoring zwitterionic antioxidant. Nat. Energy 5, 870–880 (2020).
Lin, R. et al. Monolithic all-perovskite tandem solar cells with 24.8% efficiency exploiting comproportionation to suppress Sn(II) oxidation in precursor ink. Nat. Energy 4, 864–873 (2019).
Tong, J. et al. Carrier lifetimes of >1 μs in Sn–Pb perovskites enable efficient all-perovskite tandem solar cells. Science 364, 475–479 (2019).
Eperon, G. E. et al. Perovskite–perovskite tandem photovoltaics with optimized band gaps. Science 354, 861–865 (2016).
Lin, R. et al. All-perovskite tandem solar cells with improved grain surface passivation. Nature 603, 73–78 (2022).
Palmstrom, A. F. et al. Enabling flexible all-perovskite tandem solar cells. Joule 3, 2193–2204 (2019).
Al-Ashouri, A. et al. Conformal monolayer contacts with lossless interfaces for perovskite single junction and monolithic tandem solar cells. Energy Environ. Sci. 12, 3356–3369 (2019).
Ali, F., Roldán-Carmona, C., Sohail, M. & Nazeeruddin, M. K. Applications of self-assembled monolayers for perovskite solar cells interface engineering to address efficiency and stability. Adv. Energy Mater. 10, 2002989 (2020).
Kim, S. Y., Cho, S. J., Byeon, S. E., He, X. & Yoon, H. J. Self-assembled monolayers as interface engineering nanomaterials in perovskite solar cells. Adv. Energy Mater. 10, 2002606 (2020).
Choi, K. et al. A short review on interface engineering of perovskite solar cells: a self-assembled monolayer and its roles. Sol. RRL 4, 1900251 (2020).
Aktas, E. et al. Understanding the perovskite/self-assembled selective contact interface for ultra-stable and highly efficient p–i–n perovskite solar cells. Energy Environ. Sci. 14, 3976–3985 (2021).
Magomedov, A. et al. Self-assembled hole transporting monolayer for highly efficient perovskite solar cells. Adv. Energy Mater. 8, 1801892 (2018).
Phung, N. et al. Enhanced self-assembled monolayer surface coverage by ALD NiO in p–i–n perovskite solar cells. ACS Appl. Mater. Interfaces 14, 2166–2176 (2022).
Singh, N. & Tao, Y. Effect of surface modification of nickel oxide hole-transport layer via self-assembled monolayers in perovskite solar cells. Nano Select 2, 2390–2399 (2021).
Yalcin, E. et al. Semiconductor self-assembled monolayers as selective contacts for efficient PiN perovskite solar cells. Energy Environ. Sci. 12, 230–237 (2019).
Rezaei Kolahchi, A., Carreau, P. J. & Ajji, A. Surface roughening of PET films through blend phase coarsening. ACS Appl. Mater. Interfaces 6, 6415–6424 (2014).
Yoon, H., Kang, S. M., Lee, J. K. & Choi, M. Hysteresis-free low-temperature-processed planar perovskite solar cells with 19.1% efficiency. Energy Environ. Sci. 9, 2262–2266 (2016).
Shen, L. et al. Integration of perovskite and polymer photoactive layers to produce ultrafast response, ultraviolet-to-near-infrared, sensitive photodetectors. Mater. Horiz. 4, 242–248 (2017).
Lange, I. et al. Tuning the work function of polar zinc oxide surfaces using modified phosphonic acid self-assembled monolayers. Adv. Funct. Mater. 24, 7014–7024 (2014).
Al-Ashouri, A. et al. Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction. Science 370, 1300–1309 (2020).
Kiermasch, D. et al. Unravelling steady-state bulk recombination dynamics in thick efficient vacuum-deposited perovskite solar cells by transient methods. J. Mater. Chem. A 7, 14712–14722 (2019).
Wolff, C. M. et al. Orders of recombination in complete perovskite solar cells-linking time-resolved and steady-state measurements. Adv. Energy Mater. 11, 2101823 (2021).
Abate, A. et al. Supramolecular halogen bond passivation of organic–inorganic halide perovskite solar cells. Nano Lett. 14, 3247–3254 (2014).
Krogmeier, B., Staub, F., Grabowski, D., Rau, U. & Kirchartz, T. Quantitative analysis of the transient photoluminescence of CH3NH3PbI3/PC61BM heterojunctions by numerical simulations. Sustain. Energy Fuels 2, 1027–1034 (2018).
Kirchartz, T., Márquez, J. A., Stolterfoht, M. & Unold, T. Photoluminescence-based characterization of halide perovskites for photovoltaics. Adv. Energy Mater. 10, 1904134 (2020).
Stolterfoht, M. et al. Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells. Nat. Energy 3, 847–854 (2018).
Caprioglio, P. et al. On the relation between the open-circuit voltage and quasi-fermi level splitting in efficient perovskite solar cells. Adv. Energy Mater. 9, 1901631 (2019).
Wang, R. et al. Constructive molecular configurations for surface-defect passivation of perovskite photovoltaics. Science 366, 1509–1513 (2019).
Kim, J., Chung, C.-H. & Hong, K.-H. Understanding of the formation of shallow level defects from the intrinsic defects of lead tri-halide perovskites. Phys. Chem. Chem. Phys. 18, 27143–27147 (2016).
Yin, W.-J., Shi, T. & Yan, Y. Unusual defect physics in CH3NH3PbI3 perovskite solar cell absorber. Appl. Phys. Lett. 104, 063903 (2014).
Park, S. et al. Interaction and ordering of vacancy defects in NiO. Phys. Rev. B 77, 134103 (2008).
Luo, X. et al. Record photocurrent density over 26 mA cm−2 in planar perovskite solar cells enabled by antireflective cascaded electron transport layer. Sol. RRL 4, 2000169 (2020).
Dai, Z. et al. Interfacial toughening with self-assembled monolayers enhances perovskite solar cell reliability. Science 372, 618–622 (2021).
Ramirez, C., Yadavalli, S. K., Garces, H. F., Zhou, Y. & Padture, N. P. Thermo-mechanical behavior of organic–inorganic halide perovskites for solar cells. Scr. Mater. 150, 36–41 (2018).
Dong, Q. et al. Interpenetrating interfaces for efficient perovskite solar cells with high operational stability and mechanical robustness. Nat. Commun. 12, 973 (2021).
Yadavalli, S. K., Dai, Z., Zhou, H., Zhou, Y. & Padture, N. P. Facile healing of cracks in organic–inorganic halide perovskite thin films. Acta Mater. 187, 112–121 (2020).
Dong, Q. et al. Flexible perovskite solar cells with simultaneously improved efficiency, operational stability, and mechanical reliability. Joule 5, 1587–1601 (2021).
Meng, X. et al. Bio-inspired vertebral design for scalable and flexible perovskite solar cells. Nat. Commun. 11, 3016 (2020).
Yang, M. et al. Square-centimeter solution-processed planar CH3NH3PbI3 perovskite solar cells with efficiency exceeding 15%. Adv. Mater. 27, 6363–6370 (2015).
Hambsch, M., Lin, Q., Armin, A., Burn, P. L. & Meredith, P. Efficient, monolithic large area organohalide perovskite solar cells. J. Mater. Chem. A 4, 13830–13836 (2016).
Castro-Hermosa, S., Top, M., Dagar, J., Fahlteich, J. & Brown, T. M. Quantifying performance of permeation barrier-encapsulation systems for flexible and glass-based electronics and their application to perovskite solar cells. Adv. Electron. Mater. 5, 1800978 (2019).
Wolff, C. M. et al. Perfluorinated self-assembled monolayers enhance the stability and efficiency of inverted perovskite solar cells. ACS Nano 14, 1445–1456 (2020).
Han, Q. et al. Low-temperature processed inorganic hole transport layer for efficient and stable mixed Pb–Sn low-bandgap perovskite solar cells. Sci. Bull. 64, 1399–1401 (2019).
Deng, X. et al. Dynamic study of the light soaking effect on perovskite solar cells by in-situ photoluminescence microscopy. Nano Energy 46, 356–364 (2018).
This work was financially supported by the National Natural Science Foundation of China (61974063, U21A2076, 61904109, 62125402), Natural Science Foundation of Jiangsu Province (BK20202008, BK20190315), Fundamental Research Funds for the Central Universities (0213/14380206; 0205/14380252), the Technology Innovation Fund of Nanjing University, Frontiers Science Center for Critical Earth Material Cycling Fund (DLTD2109), the Program A for Outstanding PhD Candidate of Nanjing University and Program for Innovative Talents and Entrepreneur in Jiangsu. Calculations were performed in part at the high-performance computing centre of Jilin University. We thank W. Cai and L. Zhou from Horiba for their help on TRPL measurements.
The authors declare no competing interests.
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Supplementary Figs. 1–47, Notes 1–6, Tables 1–7 and References 1–45.
PV parameters of flexible WBG PSCs shown in Supplementary Fig. 9.
PV parameters of rigid WBG PSCs shown in Supplementary Fig. 15.
Grain size measurements of perovskite films shown in Supplementary Fig. 20c,d.
The individual values of the PLQY, QFLS and Voc-imp non-radiative recombination loss of the MB-NiO/perovskite junctions used in Supplementary Table 4.
The individual values of the PLQY and QFLS of the HTL/perovskite/C60 junctions used in Supplementary Table 5.
The individual values of the PLQY, QFLS and Voc-imp non-radiative recombination loss of different perovskite junctions used in Table 1.
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Li, L., Wang, Y., Wang, X. et al. Flexible all-perovskite tandem solar cells approaching 25% efficiency with molecule-bridged hole-selective contact. Nat Energy (2022). https://doi.org/10.1038/s41560-022-01045-2