Alkyl‐Chain‐Regulated Charge Transfer in Fluorescent Inorganic CsPbBr3 Perovskite Solar Cells

• Published in: Angewandte Chemie International Edition Vol. 59; no. 11; pp. 4391 - 4395
• Main Authors: Duan, Jialong, Wang, Yudi, Yang, Xiya, Tang, Qunwei
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 09.03.2020
• Edition: International ed. in English
• Subjects: Absorption; Absorption spectra; Carbon; chain length; Chains; Charge transfer; Conductors; Dipoles; Energy conversion efficiency; Fluorescence; Incident light; inorganic perovskite solar cells; Irradiation; Light irradiation; Maximum power; Perovskites; Photovoltaic cells; Photovoltaics; Quantum dots; Quantum tunnelling; Radiation; Recombination; Solar cells; Solar power; Surface charge; surface chemistry
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202000199

Improved charge extraction and wide spectral absorption promote power conversion efficiency of perovskite solar cells (PSCs). The state‐of‐the‐art carbon‐based CsPbBr3 PSCs have an inferior power output capacity because of the large optical band gap of the perovskite film and the high energy barrier at perovskite/carbon interface. Herein, we use alkyl‐chain regulated quantum dots as hole‐conductors to reduce charge recombination. By precisely controlling alkyl‐chain length of ligands, a balance between the surface dipole induced charge coulomb repulsive force and quantum tunneling distance is achieved to maximize charge extraction. A fluorescent carbon electrode is used as a cathode to harvest the unabsorbed incident light and to emit fluorescent light at 516 nm for re‐absorption by the perovskite film. The optimized PSC free of encapsulation achieves a maximum power conversion efficiency up to 10.85 % with nearly unchanged photovoltaic performances under 80 %RH, 80 °C, or light irradiation in air. Chain gang: Regulating the alkyl‐chain length of quantum dots attached to inorganic CsPbBr3 perovskites maximizes charge extraction and transfer at the perovskite/carbon interface. The optimized inorganic CsPbBr3 perovskite solar cell (PSC) with C12 alkyl chain QDs yields an efficiency of up to 10.85 %.