Improved lifetimes of organic solar cells with solution‐processed molybdenum oxide anode‐modifying layers

We report on the use and stability of solution‐processed molybdenum oxide (sMoO x ) thin films as anode‐modifying layers to replace conventionally used poly(3,4‐ethyldioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) layers in poly(3‐hexylthiophene):[6,6]‐phenyl C 61 butyric acid methyl ester (P3HT/PC 61 BM) bulk heterojunction organic solar cells. Our results show that while as prepared devices using the two anode‐modifying layers possess similar performances, the sMoO x devices exhibit a staggering 20‐fold stability improvement in its performance half‐life compared with PEDOT/PSS devices, ~3400 h versus ~150 h, respectively. A further comparison of the stability between encapsulated and unencapsulated devices demonstrates the necessity for protection from atmospheric moisture and oxygen but again highlights the lucrative nature of sMoO x as a protective anode‐modifying layer compared with PEDOT/PSS even under ambient conditions. Copyright © 2014 John Wiley & Sons, Ltd.