Low-Temperature Solution-Processed Mg:SnO₂ Nanoparticles as an Effective Cathode Interfacial Layer for Inverted Polymer Solar Cell

Abstract

An efficient inverted polymer solar cell (PSC)-based on bulk heterojunction composites of poly(3-hexylthiophene) (P3HT) and phenyl C61-butryricacid methyl ester (PCBM) has been demonstrated by incorporating facile low-temperature solution-processed Mg-doped SnO2 (Mg:SnO2) nanoparticles as the cathode interfacial layer. Compared to the pure SnO2, the PSCs based on Mg:SnO2 interfacial layer exhibits excellent properties with a power conversion efficiency (PCE) of up to 4.08%, increased from 2.77%, corresponding to a significant 47.29% PCE enhancement. The improved photovoltaic performance is ascribed to the increased electron mobility, elevated electrical conductivity and optimized surface morphology, which makes it an excellent growth platform for a flat and high quality photoactive layer. Furthermore, we show the Mg:SnO2 interfacial layers to dramatically improve the electron extraction and effectively suppress the photogenerated carrier recombination. The low-temperature solution-processed SnO2 with Mg doping is proposed as ideal interfacial contender for PSCs and other organic electronic devices requiring electron transport layers.