Anti-dimerization 56π-electron fullerene adduct bearing bulky functional groups for inverted perovskite solar cells with enhanced interfacial stability

Solution-processible fullerene derivatives have been extensively used as electron transport layers (ETLs) of inverted perovskite solar cells (PSCs); however, the commonly used 58π-electron [6,6]-phenyl-C<sub>61</sub>-butyric acid methyl ester (PCBM) often tends to dimerize, especially under continuous illumination, severely compromising long-term stability. Herein, we develop a 1,4-unsymmetrical addition strategy and synthesize two novel 56π-electron fullerene derivatives bearing multiple bulky functional groups such as <i>tert</i>-butyl, indole and azaindole, designated as C<sub>60</sub>-TFB and C<sub>60</sub>-TFP, which not only play the role of anti-dimerization but also leverage a combined passivating effect of various heteroatom-containing functional groups. These groups establish robust interfacial bonding, enhancing interfacial stability by inhibiting the migration of iodide ions (I<sup>-</sup>) and silver (Ag). Consequently, C<sub>60</sub>-TFB and C<sub>60</sub>-TFP exhibit excellent optoelectronic properties, enabling favorable energy level alignment with perovskites. PSC devices based on C<sub>60</sub>-TFB and C<sub>60</sub>-TFP ETLs achieve a significantly enhanced power conversion efficiency (PCE) of 25.55% and 25.93%, respectively, relative to a 24.08% PCE for the PCBM-based control devices. After over 1000 h of continuous illumination at 55°C, the optimized C<sub>60</sub>-TFP-based devices demonstrate excellent stability, retaining 81.9% of their initial efficiency, whereas only 62.9% retention is achieved for the PCBM-based control device, indicating a dramatic enhancement of operational stability.

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Publication Details

Journal
National Science Review
Published
2025-10-29
DOI
https://doi.org/10.1093/nsr/nwaf466
Primary Topic
Perovskite Materials and Applications
Type
article
Field-Weighted Citation Impact
0.00

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article

Anti-dimerization 56π-electron fullerene adduct bearing bulky functional groups for inverted perovskite solar cells with enhanced interfacial stability

Zhengguo Xiao, Haibo Fan, Xiao Cheng Zeng, Zhimin Fang et al.
National Science Review
Perovskite Materials and Applications
article

Anti-dimerization 56π-electron fullerene adduct bearing bulky functional groups for inverted perovskite solar cells with enhanced interfacial stability

Zhengguo Xiao, Haibo Fan, Xiao Cheng Zeng, Zhimin Fang, Qiyuan He, Shan‐Tao Zhang, Shangfeng Yang, Sheng-Hu Yuan, Rongyao Lv, Xu Pan, Shuaihua Lu, Zonglong Zhu, Fei Li, Yuchen Li, Tao Chen, Xinyu Li, Xue Wang, Wenjing Chen, Chunlei Zhang, Zheng Liang, Xinyi Han
article en

Abstract

Solution-processible fullerene derivatives have been extensively used as electron transport layers (ETLs) of inverted perovskite solar cells (PSCs); however, the commonly used 58π-electron [6,6]-phenyl-C<sub>61</sub>-butyric acid methyl ester (PCBM) often tends to dimerize, especially under continuous illumination, severely compromising long-term stability. Herein, we develop a 1,4-unsymmetrical addition strategy and synthesize two novel 56π-electron fullerene derivatives bearing multiple bulky functional groups such as <i>tert</i>-butyl, indole and azaindole, designated as C<sub>60</sub>-TFB and C<sub>60</sub>-TFP, which not only play the role of anti-dimerization but also leverage a combined passivating effect of various heteroatom-containing functional groups. These groups establish robust interfacial bonding, enhancing interfacial stability by inhibiting the migration of iodide ions (I<sup>-</sup>) and silver (Ag). Consequently, C<sub>60</sub>-TFB and C<sub>60</sub>-TFP exhibit excellent optoelectronic properties, enabling favorable energy level alignment with perovskites. PSC devices based on C<sub>60</sub>-TFB and C<sub>60</sub>-TFP ETLs achieve a significantly enhanced power conversion efficiency (PCE) of 25.55% and 25.93%, respectively, relative to a 24.08% PCE for the PCBM-based control devices. After over 1000 h of continuous illumination at 55°C, the optimized C<sub>60</sub>-TFP-based devices demonstrate excellent stability, retaining 81.9% of their initial efficiency, whereas only 62.9% retention is achieved for the PCBM-based control device, indicating a dramatic enhancement of operational stability.

National Science ReviewVol. 12(12)
Anhui University (CN), City University of Hong Kong (HK), Hefei Institutes of Physical Science (CN), Collaborative Innovation Center of Chemistry for Energy Materials (CN), Yangzhou University (CN)
City University of Hong Kong, National Natural Science Foundation of China, Chinese Academy of Sciences, Natural Science Foundation of Guangdong Province, University of Science and Technology of China, Innovation and Technology Fund, Fundamental Research Funds for the Central Universities
Openalex Percentile: Top 69%
Perovskite Materials and Applications
DOIOpen Access PDFOpenAlex
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