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.

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► Hybrid ZnO nanoparticle:P3HT solar cells with varied architectures are compared.
► Blended devices display efficiency up to nine times that of bilayer devices.
► Blend devices with a conventional architecture degrade sharply with light exposure.
► In contrast, inverted blend devices have improved stability with light exposure.
► These inverted blends are achieved using a pH neutralized hole transport layer.