Quantum-Sized SnO<sub>2</sub> Nanoparticles with Upshifted Conduction Band: A Promising Electron Transportation Material for Quantum Dot Light-Emitting Diodes
Yue Liu, Song Wei, Gang Wang, Junye Tong, Jing Li, Daocheng Pan
Abstract
In previous reports of the literature, ZnO nanoparticles were unexceptionally used as the electron transportation material in highly efficient CdSe-based quantum dot light-emitting diodes (QD-LEDs). However, as an amphoteric oxide, ZnO nanoparticles are chemically unstable in air. Here, we utilize quantum-sized SnO2 nanoparticles as the electron transportation layer (ETL) of CdSe-based QD-LEDs. Decreasing the size of SnO2 nanoparticles will upshift the conduction band from −4.50 to −3.84 eV based on the quantum size effect, which is beneficial to facilitate electron injection into the QD emitting layer. Our investigations show that QD-LEDs based on quantum-sized SnO2 nanoparticles exhibit comparable electroluminescence properties and higher stability in contrast to ZnO nanoparticle-based QD-LEDs, demonstrating that small-sized SnO2 nanoparticles have a bright prospect due to the ETL in QD-LEDs.