A research team led by Prof. Gang Li published a paper “Stable and low-photovoltage-loss perovskite solar cells by multifunctional passivation” in the Nature Photonics journal in July 2021. Nature Photonics is a monthly journal dedicated to publish top-quality and peer-reviewed research in all areas of light generation, manipulation and detection. The journal covers research related to optoelectronics, laser science, imaging, communications and other aspects of photonics. It is regarded as a top-ranking journal in the field of photonics.
Metal halide perovskite solar cells have demonstrated a high power conversion efficiency (PCE), and further enhancement of the PCE requires a reduction of the bandgap-voltage offset (WOC) and the non-radiative recombination photovoltage loss (ΔVOC,nr). In this paper, the research team reported an effective approach for reducing the photovoltage loss through the simultaneous passivation of internal bulk defects and dimensionally graded two-dimensional perovskite interface defects. Through this dimensionally graded perovskite formation approach, an open-circuit voltage (VOC) of 1.24 V was obtained with a champion PCE of 21.54% in a 1.63 eV perovskite system (maximum VOC = 1.25 V, WOC = 0.38 V and ΔVOC,nr = 0.10 V); the team further decreased the WOC to 0.326 V in a 1.53 eV perovskite system with a VOC of 1.21 V and a PCE of 23.78% (certified 23.09%). This approach is equally effective in achieving a low WOC (ΔVOC,nr) in 1.56 eV and 1.73 eV perovskite solar cell systems, and further leads to the substantially improved operational stability of perovskite solar cells. The paper is available at https://www.nature.com/articles/s41566-021-00829-4.
