Improved performance of photovoltaic devices based on poly(3-hexylthiophene) nanofibers and CdSe quantum dots through ligand exchange and annealing treatment

Hybrid organic/inorganic solar cells based on pyridine-treated CdSe quantum dots and poly(3-hexylthiophene)(P3HT) nanofibers were fabricated. By tuning the ligands of CdSe dots and morphology modification of blend film through thermal annealing, the insulating and less stable pyridine ligands of CdSe QDs can be removed by gentle heating and modified morphology results in more efficient charge separation and transport properties, and this leads to an improved power conversion efficiency of 1.22%. These results demonstrate a promising approach to improve charge transport in the hybrid nanocrystal-polymer composite photovoltaic cells.

► Ligand exchange with pyridine improves the conductivity of CdSe dots.
► Thermal annealing gets rid of organics covered the surface of CdSe dots.
► Optimized the morphology and transport result in improved efficiency of device .