Over 100‐nm‐Thick MoOx Films with Superior Hole Collection and Transport Properties for Organic Solar Cells

Abstract

AbstractHerein, a novel and effective method to prepare n‐doped MoOx films with highly improved conductivity is reported. The MoOx films are readily prepared by spin‐coating an aqueous solution containing ammonium molybdate tetrahydrate and vitamin C (VC). As confirmed by UV–vis absorption, X‐ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy measurements, Mo(VI) is partially reduced to Mo(V) by VC, resulting in the n‐doping of MoOx. The conductivity of the n‐doped MoOx (H:V‐Mo) film can be enhanced by four orders of magnitude compared to pristine MoOx (H‐Mo), that is, from 1.2 × 10−7 to 1.1 × 10−3 S m−1. The device using a 10 nm H:V‐Mo anode interlayer (AIL) exhibits comparable photovoltaic performance to a poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)‐modified device. More importantly, the hole transport and collection properties of the H:V‐Mo AILs show outstanding tolerance to thickness variation, that is, with increasing thickness of the H:V‐Mo AIL from 10 to 150 nm, the V oc and fill factor values of the devices remain unchanged. The device based on the blade‐coated H:V‐Mo AIL also has a high power conversion efficiency of 10.6%. To the best of the authors' knowledge, this work demonstrates the first example to prepare metal oxide AILs with outstanding tolerance to thickness, which is promising for the future large‐area manufacturing.