Cu_2ZnSnSe_4 quantum dots with controllable size and quantum confinement effect

摘要

Cu_2ZnSnSe_4 quantum dots (QDs) with controllable sizes have been synthesized via a hot-injection method. The diameters of the QDs range from 3.2 to 10.1 nm with the tunable band gap from 1.27 to 1.54 eV by adjusting the reaction temperatures from 180 to 240°C. Structural and Raman scattering data confirm that Cu_2ZnSnSe_4 is obtained without other secondary phases. The band gaps of the QDs with diameters less than 4.6 nm show an obvious blue shift to higher energy due to quantum confinement effect. It indicates that the Cu_2ZnSnSe_4 QDs can be a potential candidate for quantum-dot-sensitized solar cells in the future.