High glass transition temperature dopant-free hole transport material via D-A-π-A-D-strategy for perovskite solar cell

• Published in: Rare metals Vol. 43; no. 12; pp. 6373 - 6383
• Main Authors: Liao, Cheng-Hui, Yuan, Li-Gang, Zhang, Yi-Heng, Zhu, Wei-Ya, Qin, Min-Chao, He, Zhi-Bo, Huang, Jie-Lin, Xiao, Hao-Lin, Li, Zhi-Heng, Lu, Xin-Hui, Yan, Ke-You, Li, Yuan
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.12.2024; Springer Nature B.V
• Subjects: Biomaterials; Chemical synthesis; Chemistry and Materials Science; Commercialization; Decomposition reactions; Dopants; Electron paramagnetic resonance; Energy; Energy conversion efficiency; Glass transition temperature; Hole mobility; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Organic semiconductors; Original Article; Perovskites; Photovoltaic cells; Physical Chemistry; Solar cells; Spin coating; Stability; Thermal decomposition; D-A-π-A-D; High glass transition temperature; Dopant-free; Perovskite solar cells; Hole transport materials
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-024-02881-9

Despite the great leap forward perovskite solar cells (PSCs) have achieved in power conversion efficiency, the device instability remains one of the major problems plaguing its commercialization. Dopant-free hole transport material (HTM) has been widely studied as an important strategy to improve the stability of PSCs due to its avoidance of moisture-sensitive dopants and cumbersome doping process. In this work, a series of dopant-free HTMs L1F, L2F and L3F based on D-A-π-A-D configuration were synthesized through two steps of reaction. L3F presents a high glass transition temperature of 180 °C and thermal decomposition temperature of 448 °C. Notably, electron paramagnetic resonance signals of L1F, L2F and L3F powders indicate the open-shell quinoidal diradical resonance structure in their aggregation state due to aggregation-induced radical effect. All these HTMs present higher hole mobility than dopant-free Spiro-OMeTAD, and the dopant-free L3F-based PSC device achieves the highest power conversion efficiency of 17.6% among them. In addition, due to the high hydrophobic properties of L1F, L2F and L3F, the perovskite films spin-coated with these HTMs exhibit higher humidity stability than doped Spiro-OMeTAD. These results demonstrate a promising design strategy for high glass transition temperature dopant-free hole transport material. The open-shell quinoid-radical organic semiconductors are not rational candidates for dopant-free HTMs for PSC devices. Graphic abstract