Effect of emissive quantum cluster consisting of 22 Au atoms on the performance of semi-transparent plastic solar cells under low intensity illumination

In this study, we present efficient semi-transparent solar cells with enhanced performance at low intensity illumination via the incorporation of emissive quantum clusters consisting of 22 Au atoms. The inclusion of Au22 quantum clusters (Au22-QCs) in semi-transparent solar cells led to a substantial reduction of the dependence on the incident light intensity as well as an increase in device efficiency. For the control semi-transparent solar cell, which has ~ 25% transparency, there was a 35% drop in efficiency with a light intensity decrease of 40% (0.6 sun). However, for the semi-transparent solar cell with Au22-QCs, there was only a 15% drop in efficiency under 0.6 sun irradiation. Less dependence on incident light intensity can be a great advantage in the practical use of semi-transparent solar cells. The change in the intensity of the incident light can also be caused by simply changing the angle of the light and device. Thus, the performance of general solar cells is strongly dependent on the angle of incident light. However, such angle dependence was effectively suppressed in solar cells with Au22-QCs. Furthermore, less dependence on the angle of incidence light offered a great advantage in driving flexible solar cells. The performance difference between the flat state and bending state was significantly reduced in our semi-transparent flexible solar cell with Au22-QCs.