The solvothermal method is used to prepare CuInSe2 quantum dots (QDs). This method mainly uses ethanolamine as a solvent with CuCl2·2H2O, InCl3·4H2O, and selenium powder used as raw materials. The powder morphology, phase, and light absorption characteristics of different reaction temperatures and times were characterized in this work. Other characterization methods were used to optimize the CuInSe2QDs. It was substantiated that the optimum reaction condition is at 180 °C for 20 h, the proportion of Cu, In, and Se is 1:2:1, the particle size is 10 nm, and the emission peak is at 800 nm. Furthermore, the CuInSe2QDs with the best performance were adsorbed on the TiO2 film, and it was concluded that TiO2 could be successfully decorated via the CuInSe2QDs, and the absorption band edge was enlarged to enhance the light absorption performance.
