Polymer–metal-oxide hybrid solar cells

Abstract

Polymer solar cells have great potential for offering a cost-effective approach for converting solar energy into electricity compared to traditional inorganic counterparts. Besides the most intensively studied materials for polymer solar cells consisting of conducting polymer and fullerene derivative hybrids, polymer–inorganic nanocrystal (NC) hybrid solar cell devices represent promising alternatives by taking advantage of the relatively high electron mobility, good physical and chemical stability and various morphologies of inorganic NCs. This paper presents a review of the current status and development of polymer–inorganic hybrid solar cells based on metal oxide NCs by focusing the discussion on TiO₂ and ZnO. These metal oxide NC materials are promising acceptor candidates because they are environmentally friendly and cheap to be synthesized by using wet chemical methods with a wide range of morphologies, enabling full compatibility with the solution-processable fabrication of polymer solar cells. Substantial progress has been achieved recently in the power conversion efficiencies of polymer–metal-oxide hybrid solar cells through the control of nanoscale polymer–inorganic hybrid morphologies and the improved interfaces between polymers and inorganic nanocrystals. We also reviewed the recently developed state-of-the-art analytical techniques introduced to reveal the nanoscale morphological organization of polymers and NCs in polymer–metal-oxide hybrid solar cells, which provides the understanding of the interplay between controlling nanoscale morphologies of polymer–metal-oxide NC hybrids and photocarrier dynamics and the corresponding device performance. Finally, the main challenges in the development of polymer–metal-oxide hybrid solar cells consisting of both bulk heterojunctions (BHJs) and nanostructured hybrid device architectures are identified, and strategies for improving the device performances are also discussed.