Dually Modified Wide-Bandgap Perovskites by Phenylethylammonium Acetate toward Highly Efficient Solar Cells with Low Photovoltage Loss

Jiabang Chen; Deng Wang; Shi Chen; Hang Hu; Yang Li; Yulan Huang; Zhuoqiong Zhang; Zhengyan Jiang; Jiamin Xu; Xiyu Sun; Shu Kong So; Yuanjun Peng; Xingzhu Wang; Xunjin Zhu; Baomin Xu

doi:10.1021/acsami.2c10928

Dually Modified Wide-Bandgap Perovskites by Phenylethylammonium Acetate toward Highly Efficient Solar Cells with Low Photovoltage Loss

ACS Appl Mater Interfaces. 2022 Sep 28;14(38):43246-43256. doi: 10.1021/acsami.2c10928. Epub 2022 Sep 16.

Authors

Jiabang Chen^{1

2}, Deng Wang^{1

3}, Shi Chen⁴, Hang Hu¹, Yang Li¹, Yulan Huang¹, Zhuoqiong Zhang⁵, Zhengyan Jiang¹, Jiamin Xu¹, Xiyu Sun¹, Shu Kong So⁵, Yuanjun Peng⁶, Xingzhu Wang^{1

6

7}, Xunjin Zhu², Baomin Xu^{1

8

9}

Affiliations

¹ Department of Materials Science and Engineering and Shenzhen Engineering Research and Development Center for Flexible Solar Cells, Southern University of Science and Technology, Shenzhen, Guangdong Province 518055, China.
² Department of Chemistry and Institute of Molecular Functional Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong 999077, Hong Kong, China.
³ Department of Materials Science and Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China.
⁴ Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng 475004, China.
⁵ Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Kowloon Tong 999077, Hong Kong, China.
⁶ Shenzhen Putai Technology Co., Ltd, Shenzhen 518110, China.
⁷ SUSTech Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong Province 518055, China.
⁸ Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China.
⁹ Key Laboratory of Energy Conversion and Storage Technologies (Southern University of Science and Technology), Ministry of Education, Shenzhen 518055, China.

PMID: 36112025
DOI: 10.1021/acsami.2c10928

Abstract

Wide-bandgap perovskites as a class of promising top-cell materials have shown great promise in constructing efficient perovskite-based tandem solar cells, but their intrinsic relatively low radiative efficiency results in a large open-circuit voltage (V_OC) deficit and thereby limits the whole device performance. Reducing film flaws or optimizing interfacial energy level alignments in wide-bandgap perovskite devices can efficiently inhibit nonradiative recombination to boost device V_OC and efficiency. However, the simultaneous regulation on both sides and their underlying mechanism are less explored. Herein, a bifunctional modification approach is proposed to optimize the wide-bandgap perovskite surface with an ultrathin layer of phenylethylammonium acetate (PEAAc) to synchronously decrease the surface imperfection and mitigate the interfacial energy barrier. This treatment effectively heals under-coordinated surface defects through the formation of chemical interaction between the perovskite and PEAAc, bringing about a much slower charge trapping process and dramatically decreasing nonradiative recombination losses. Meanwhile, the passivation-induced upshifted Fermi level of the perovskite contributes to accelerated electron extraction and larger Fermi-level splitting under illumination. Consequently, the PEAAc-modified wide-bandgap (1.68 eV) device achieves an optimal efficiency of 20.66% with a high V_OC of 1.25 V, among the highest reported V_OC values for wide-bandgap perovskite devices, enormously outperforming that (18.86% and 1.18 V) of the device without passivation. In addition, the radiative limit of V_OC for both cells is determined to be 1.42 V, delivering nonradiative recombination losses of 0.24 and 0.17 V for the control and PEAAc-modified devices, respectively. These results highlight the significance of the bifunctional modification strategy in achieving high-performance wide-bandgap perovskite devices.

Keywords: interfacial energy barrier; low photovoltage loss; nonradiative recombination; perovskite solar cells; surface modification; wide-bandgap perovskite.