Midinfrared Electroluminescence from CdSe Quantum Dots

Midinfrared electroluminescence from the electron intraband transition is demonstrated with intrinsic CdSe colloidal quantum dots. The device consists of a thin film of CdSe dots and a layer of ZnO nanocrystals, sandwiched between two electrodes that enhance light outcoupling at 5 μm. At 100 mA and 15 V, the electron-to-photon efficiency is 0.40%, and the power conversion efficiency is 0.013%. The devices show good air and thermal stability. Electron transport layers and surface traps are discussed.