Solvothermal preparation of yellow-emitting CuInS2/ZnS quantum dots and their application to white light-emitting diodes.

Based on the development of highly fluorescent colloidal quantum dots (QDs), their successful applications for the fabrication of lighting sources such as light-emitting diodes (LEDs) and lasing devices have been demonstrated. Here, CuInS2/ZnS core/shell QDs are facilely prepared by a two-step solvothermal route. Depending on the amount of a shell precursor of Zn stearate, fluorescent properties such as emission color and quantum yield (QY) of CuInS2/ZnS QDs are tunable and optimized. Yellow-emitting CuInS2/ZnS QD with a peak wavelength of 562 nm, QY of 81%, and emission bandwidth of 114 nm is chosen as an efficient blue-to-yellow downconverter for the fabrication of QD-based white LED (WLED). Various electroluminescent properties including luminous efficacy and color rendering index of QD-WLED are measured as a function of forward current up to 100 mA and described in details.