Phosphine Oxide Derivative as a Passivating Agent to Enhance the Performance of Perovskite Solar Cells
Albertus Adrian Sutanto, Cansu Igci, Hobeom Kim, Hiroyuki Kanda, Naoyuki Shibayama, Mounir Mensi, Valentin I. E. Queloz, Cristina Momblona, Hyung Joong Yun, Henk J. Bolink, Aron J. Huckaba, Mohammad Khaja Nazeeruddin
Abstract
Defects of metal-halide perovskites detrimentally influence the optoelectronic properties of the thin film and, ultimately, the photovoltaic performance of perovskite solar cells (PSCs). Especially, defect-mediated nonradiative recombination that occurs at the perovskite interface significantly limits the power conversion efficiency (PCE) of PSCs. In this regard, interfacial engineering or surface treatment of perovskites has become a viable strategy for reducing the density of surface defects, thereby improving the PCE of PSCs. Here, an organic molecule, tris(5-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)phosphine oxide (THPPO), is synthesized and introduced as a defect passivation agent in PSCs. The P═O terminal group of THPPO, a Lewis base, can passivate perovskite surface defects such as undercoordinated Pb2+. Consequently, improvement of PCEs from 19.87 to 20.70% and from 5.84 to 13.31% are achieved in n–i–p PSCs and hole-transporting layer (HTL)-free PSCs, respectively.