Blue Light Emitting Diodes based on Bright Quasi‐Type‐II ZnO@1‐Aminopyrene Hybrid Quantum Dots with a Long Operation Life

Abstract

Non‐toxic heavy metal, low‐cost indium‐free blue emissive quantum dots (QDs) are critical for the realization of self‐emissive electroluminescent quantum dot (ELQD) light‐emitting diode (LED) displays. A facile and effective hybridization of ZnO QDs with functionalized polyaromatic hydrocarbons (f‐PAHs) to synthesize a very bright and stable blue‐light emissive quantum‐dot LED (QLED) using non‐toxic quasi‐type‐II ZnO@1‐Aminopyrene hybrid QDs is reported. The optimized QLEDs of ITO/PEDOT:PSS/TFB/ZnO@1‐Aminopyrene/TPBi/LiF/Al demonstrate very bright deep blue‐light electroluminescence of 3379 cd m−2 centered at λ = 441 nm with a full‐width‐at‐half maximum of 41.7 nm and CIE 1931 color coordinates of 0.17 and 0.09, a luminous efficacy of 3.32 cd A−1, power efficiency of 2.45 lm W−1, external quantum efficiency of 2.35%, and a remarkably long lifetime T50 of >17 830 h at 100 cd m−2.

Crystal Structure and Optical Properties of ZnO:Ce Nano Film

“…ZnO has excellent chemical stability because of its hexagonal wurtzite structure at normal temperatures leading to a large Coulomb force for its positive and negative electron pairs [1]. ZnO is environmentally friendly, inexpensive, and abundant in nature and intrinsic defects such as oxygen vacancies or Zn interstitials are mostly on the surface of ZnO causing visible emissions [2,3]. All these unique properties make ZnO application in the ultraviolet (UV) and blue source and have efficient exciton emission [4].…”