Zinc oxide nanoparticles as electron transporting interlayer in organic solar cells

Abstract

Zinc oxide nanoparticles (ZnO NPs) are among the well-known electron transporting layers (ETLs) in flexible electronics, especially in organic solar cells (OSCs). This is due to their high mobility and transparency, annealing-free and solution-processable features, large-area fabrication technique compatibility, etc. This review summarizes the synthetic methods of ZnO NPs with the aim to achieve homogeneous, size-controllable, and long-term stable ZnO NPs colloidal dispersions. Different strategies have been summarized to modify ZnO NPs in terms of surface traps, work function, dispersity, conductivity, and surface energy. The modifications were generally utilized to realize high-quality ETLs and ultimately improve the performance and stability of OSC devices. The large-area fabrication techniques for coating or printing ZnO NPs films are also discussed. We hope that this review will highlight the importance of ZnO NPs and inspire researchers to employ ZnO NPs in other electronic devices.