Multifunctional Crosslinking-Enabled Strain-Regulating Crystallization for Stable, Efficient α-FAPbI3 -Based Perovskite Solar Cells

Hengkai Zhang; Zhiliang Chen; Minchao Qin; Zhiwei Ren; Kuan Liu; Jiaming Huang; Dong Shen; Zehan Wu; Yaokang Zhang; Jianhua Hao; Chun-Sing Lee; Xinhui Lu; Zijian Zheng; Wei Yu; Gang Li

doi:10.1002/adma.202008487

Multifunctional Crosslinking-Enabled Strain-Regulating Crystallization for Stable, Efficient α-FAPbI₃ -Based Perovskite Solar Cells

Adv Mater. 2021 Jul;33(29):e2008487. doi: 10.1002/adma.202008487. Epub 2021 Jun 4.

Authors

Hengkai Zhang^{1

2}, Zhiliang Chen¹, Minchao Qin³, Zhiwei Ren^{1

2}, Kuan Liu^{1

2}, Jiaming Huang^{1

2}, Dong Shen⁴, Zehan Wu⁵, Yaokang Zhang⁶, Jianhua Hao⁵, Chun-Sing Lee⁴, Xinhui Lu³, Zijian Zheng⁶, Wei Yu^{1

7}, Gang Li^{1

2}

Affiliations

¹ Department of Electronic and Information Engineering, Research Institute for Smart Energy (RISE), The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
² Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen, 518057, China.
³ Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong, China.
⁴ Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China.
⁵ Department of Applied Physics, The Hong Kong Polytechnic University, New Territories, Hong Kong, China.
⁶ Laboratory for Advanced Interfacial Materials and Devices, Research Centre for Smart Wearable Technology, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
⁷ State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian, Liaoning, 116023, China.

PMID: 34085738
DOI: 10.1002/adma.202008487

Abstract

α-Formamidinium lead triiodide (α-FAPbI₃ ) represents the state-of-the-art for perovskite solar cells (PSCs) but experiences intrinsic thermally induced tensile strain due to a higher phase-converting temperature, which is a critical instability factor. An in situ crosslinking-enabled strain-regulating crystallization (CSRC) method with trimethylolpropane triacrylate (TMTA) is introduced to precisely regulate the top section of perovskite film where the largest lattice distortion occurs. In CSRC, crosslinking provides in situ perovskite thermal-expansion confinement and strain regulation during the annealing crystallization process, which is proven to be much more effective than the conventional strain-compensation (post-treatment) method. Moreover, CSRC with TMTA successfully achieves multifunctionality simultaneously: the regulation of tensile strain, perovskite defects passivation with an enhanced open-circuit voltage (V_OC = 50 mV), and enlarged perovskite grain size. The CSRC approach gives significantly enhanced power conversion efficiency (PCE) of 22.39% in α-FAPbI₃ -based PSC versus 20.29% in the control case. More importantly, the control PSCs' instability factor-residual tensile strain-is regulated into compression strain in the CSRC perovskite film through TMTA crosslinking, resulting in not only the best PCE but also outstanding device stability in both long-term storage (over 4000 h with 95% of initial PCE) and light soaking (1248 h with 80% of initial PCE) conditions.

Keywords: crosslinking; defect passivation; perovskite solar cells; strain regulation; α-FAPbI 3.

Abstract

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