Effect of device architecture on hybrid zinc oxide nanoparticle:poly(3- hexylthiophene) blend solar cell performance and stability

Hybrid zinc oxide nanoparticle (ZnO np):poly(3-hexylthiophene) (P3HT) photovoltaic devices with a blend morphology in the active layer show up to a ninefold improvement in device efficiency above devices with a planar donor-acceptor interface. However, blend devices in a conventional architecture have very poor stability upon white light exposure. Blend devices in an inverted architecture have not been previously achieved because the commercially available poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hole transport layer etches the ZnO when PEDOT:PSS is deposited on top of the ZnO np:P3HT blend. Here we report the successful demonstration of an inverted ZnO np:P3HT blend solar cells that is made possible through the use of a pH neutralized PEDOT:PSS hole transport layer, and show how the inverted device architecture leads to greatly improved device stability under white light exposure. © 2011 Elsevier B.V. All rights reserved.