Fabrication of solar cells made with CuInTe2−xSex quantum dots sensitized hierarchical TiO2 sphere having a CuS counter electrode: Dependence on the Te/Se ratio

In this study, we have succeeded in fabricating quantum dot sensitized solar cells (QDSSC's) which utilize the semiconductor CuInTe2−xSex (of different Te/Se ratios) quantum dots sensitized hierarchical TiO2 sphere (HTS) having CuS as the photoanode. The solar to electric energy conversion performance of the resulting QDSSC depends strongly on the Te/Se ratios in the ternary chalcopyrite compound. In this study, the assembled device exhibiting the highest energy conversion efficiency η of 3.751% (Voc = 0.683 V, Jsc = 11.707 mA cm−2, FF = 0.516) is the one having CuInTe1.2Se0.8 quantum dots. This value is quite an improvement over those of the CuInTe2 (η = 1.970%) and CuInSe2 (η = 2.286%). The efficiency of the devices decreases as the Se increases.