Manganese Doped Tin Oxide for Stable and Efficient Quantum Dot Light–Emitting Diodes

Abstract As an alternative electron transport material to the chemically unstable ZnO nanoparticles (NPs), SnO 2 NPs exhibit a great potential to construct high‐performance quantum dot light‐emitting diodes (QLEDs). However, only moderate device performance has been obtained for SnO 2 ‐based QLEDs due to the low electron mobility, unfavorable energy band, and massive defects of SnO 2 NPs. Herein, a strategy of transition metal doping is reported to achieve high‐quality manganese‐doped SnO 2 (Mn‐SnO 2 ) NPs to address the above problems. Specifically, the large bond energy of Mn─O bonds reduces the oxygen vacancy defects, prompting an effective suppression of the interfacial exciton quenching for massive radiative recombination. Moreover, the favorable energy band and high electron mobility for Mn‐SnO 2 promote efficient electron injection and transportation. The good optoelectronic properties for Mn‐SnO 2 NPs contribute to a great enhancement in device efficiency from 8.2 to 11.4% and a remarkable improvement in lifetime ( T 95 ) from 565.3 to 1009.2 h at 1000 cd −2 , among the best performing ZnO‐free QLEDs. Notably, the Mn‐SnO 2 based QLEDs show a very superior shelf stability to the QLEDs based on SnO 2 and ZnO analogs. Consequently, this work reports an effective approach to achieve high‐quality SnO 2 NPs for efficient and stable QLEDs.