Quantum dot sensitized solar cells using type-II CdSe-Cu2Se core-shell QDs

Oleylamine capped CdSe-Cu2Se type-II core–shell quantum dots were synthesised by organometallic high temperature route. The nanostructures were characterized using XRD, XPS, HRTEM, optical absorption and EDS and their suitability to serve as an effective sensitizer for TiO2 deposited fluorine doped tin oxide coated glass slides was explored. Employing aqueous sulfide/polysulfide redox couple as the electrolyte, Cu2S as the counter electrode, ZnS as the surface passivation layer and TiO2 as the anode material, quantum dot sensitized solar cells were constructed. A power conversion efficiency of 4.3% was observed for the best performing device. Sintering of the photoanode, before embedding in the cell structure, resulted in an efficiency enhancement to 4.83%.