Fabrication of TiO2 nanorod array/semiconductor nanocrystal hybrid structure for photovoltaic applications

We present all-inorganic solar cells fabricated from TiO2 nanorod array and semiconductor nanocrystals. CdSe or CdTe nanocrystals are drop-casted on TiO2 nanorod arrays to form TiO2 nanorod array/semiconductor nanocrystal hybrid structure. Thermal annealing is used to remove the organic molecules on the surface of the nanocrystals which could suppress electron transport, resulting in the morphological and structural change of the nanocrystals. For CdSe nanocrystals, p-type transparent semiconductor CuSCN is introduced as solid-state electrolyte to collect holes and TiO2/CdSe/CuSCN trilayer structure is adopted. While for CdTe nanocrystals, simpler TiO2/CdTe bilayer structure is adopted. Conversion efficiency of the two solar cells reaches to 0.21% and 0.07%, respectively. The results are a step towards development of high efficiency all-inorganic TiO2 nanorod array-based solar cells.