Enhanced performance of cadmium selenide quantum dot-sensitized solar cells by incorporating long afterglow europium, dysprosium co-doped strontium aluminate phosphors

CdSe quantum dot-sensitized solar cells based on an efficient bifunctional structured layer composed of long afterglow SrAl₂O₄:Eu,Dy phosphors on top of a transparent layer of nanocrystalline TiO₂ were fabricated and their photovoltaic performances were investigated. The results show that a high power conversion efficiency of 1.22% is achieved for the cell with SrAl₂O₄:Eu,Dy at one sun illumination (AM 1.5 G, 100mWcm^-2), which is an increase of 48% compared to the cell without SrAl₂O₄:Eu,Dy (0.82%). After one sun illumination for 1min and subsequent turn off of the light source, the cell with SrAl₂O₄:Eu,Dy still shows an efficiency of 0.04% under dark condition due to the irradiation by the long persistent light from SrAl₂O₄:Eu,Dy. The present strategy should provide a possibility to fulfill the opertion of solar cells even in the dark.