Interfacial band offset engineering with barium-doping towards enhanced performance of all inorganic CsPbI2Br perovskite solar cells

• Published in: Physical chemistry chemical physics : PCCP Vol. 25; no. 42; pp. 29050 - 29060
• Main Authors: Rondiya, Sachin R, Mali, Sawanta S, Roy, Anurag, Inwati, Gajendra Kumar, Rahane, Ganesh K, Jadhav, Yogesh A, Suresh, Sunil, Debnath, Tushar, Chang Kook Hong, Dzade, Nelson Y
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.11.2023
• Subjects: Barium; Charge transport; Conduction bands; Conduction electrons; Density functional theory; Electron transport; Energy conversion efficiency; First principles; Performance enhancement; Perovskites; Photovoltaic cells; Solar cells; Titanium dioxide
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp02935b

This study investigates the incorporation of Ba2+ at a low concentration into CsPbI2Br, resulting in the formation of mixed CsPb1−xBaxI2Br perovskite films. Photovoltaic devices utilizing these Ba-doped CsPbI2Br (Ba–CsPbI2Br) perovskite films achieved a higher stabilized power conversion efficiency of 14.07% compared to 11.60% for pure CsPbI2Br films. First-principles density functional theory calculations indicate that the improved device performance can be attributed to the efficient transport of conduction electrons across the interface between Ba–CsPbI2Br and the TiO2 electron transporting layer (ETL). The Ba–CsPbI2Br/TiO2 interface exhibits a type-II staggered band alignment with a smaller conduction band offset (CBO) of 0.25 eV, in contrast to the CsPbI2Br/TiO2 interface with a CBO of 0.48 eV. The reduced CBO at the Ba–CsPbI2Br/TiO2 interface diminishes the barrier for conduction electrons to transfer from the Ba–CsPbI2Br layer to the TiO2 layer, facilitating efficient charge transport.