Robust interface engineering for High-performance and Stable inverted planar perovskite solar cells via both poly(2-ethyl-2-oxazoline) nanodots

Abstract

Low temperature, stable and facile solution processes are the typical characters in mass production of next generation solar cells, especially for flexible consumable electronics. In this work, we employed a low cost, chemical stable, solution processing polymer, thermal treatment free poly(2-ethyl-2-oxazoline) (PEOz) nanodots, as an efficient interfacial layer on top of [6,6]-phenyl-C61-butyricacid methyl (PCBM) to fabricate inverted planar heterojunction (PHJ) perovskite solar cells. The performance of perovskite solar cells increased from 9.01% to 14.52% after inserting a thin layer of PEOz between PCBM and Ag. It was demonstrated that PEOz can effectively reduce the work function of silver electrode to form an ohmic contact between PCBM and silver, which dramatically enhance the electron extraction capability from PCBM to silver electrode. This study pays a way for the large scale fabrication of high efficiency perovskite thin film solar cells via low cost solution processing at low temperatures.