Improved Photovoltaic Characteristics of Inverted Polymer Solar Cells With Indium-Doped ZnO at Low-Temperature Annealing as Electron-Transport Layer

For inverted solar cells, UV-socking is usually necessary to improve the photovoltaic performance of the devices. In this article, inverted polymer solar cells with pure and indium-doped ZnO as an electron transport layer were fabricated, and their properties were investigated. We found that the In-doped ZnO-based device has a high power conversion efficiency of 5.99%, and a nearly 40% improvement in comparison with the pure ZnO-based device without the UV treatment. Those investigations of X-ray diffraction, Photoluminescence, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectra show that the doping of indium into the lattice of ZnO can decrease defect states and increase the work function, leading to more efficient electron extraction, and consequently, an enhancement of photovoltaic performance of the device.