Fine Tuned Nanolayered Metal/Metal Oxide Electrode for Semitransparent Colloidal Quantum Dot Solar Cells

Semitransparent photovoltaics have great potential, for example, in building-integration or in portable electronics. However, the front and back contact electrodes significantly affect the light transmission and photovoltaic performance of the complete device. Herein, the use of a semitransparent nanolayered metal/metal oxide electrode for a semitransparent PbS colloidal quantum dot solar cell to increase the light transmission and power conversion efficiency is reported. The effect of the nanolayered electrode on the optical properties within the solar cells is studied and compared to a theoretically model to identify the origin of optical losses that lower the device transmission. The results show that the light transmission in the visible region and the photovoltaic performance are significantly enhanced with the nanolayered electrode. The solar cell shows an efficiency of 5.4% and average visible transmittance of 24.1%, which is an increase by 28.6% and 59.6%, respectively, compared to the device with a standard Au film as the electrode. These results demonstrate that the optical and electrical modification of transparent electrode is possible and essential for reducing the light reflection and absorption of the electrode in semitransparent photovoltaics, and, meanwhile the demonstrated nanolayered materials may provide an avenue for enhancing the device transparency and efficiency.