Controllable synthesis of ultrasmall CuInSe2 quantum dots for photovoltaic application

Abstract

Here we report the first synthesis of ultrasmall CuInSe₂ quantum dots (QDs) with diameters below the exciton Bohr radius 10.6 nm by a solvothermal method. The synthesis is conducted in oleylamine without any organometallic precursors. The quantum confinement effect has been identified in the optical absorption spectra. Through pre-loading CuInSe₂ QDs on TiO₂ film, a good electron transfer dynamics could be observed on the CdS/CuInSe₂/TiO₂ film. Under one sun of simulated irradiation, the resultant quantum dot sensitized solar cell based on CdS/CuInSe₂ exhibited a power conversion efficiency of about 2.27%, which was 55% higher than that of the single CdS sensitized solar cell. It indicates that CuInSe₂ QDs have great potential in photovoltaic applications.