CdSe/ZnS Quantum-Dot Light-Emitting Diodes With Spiro-OMeTAD as Buffer Layer

Abstract

We report a high-efficient green CdSe/ZnS quantum-dot light-emitting diode (QLED) using 2,2’,7,7’-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9’-Spirobifluorene (Spiro-OMeTAD) as an electron buffer layer. The high lowest unoccupied molecular orbital level of Spiro-OMeTAD suppresses the electron transfer and promotes the charge balance. The external quantum efficiency (EQE) of the green QLED device is increased by 1.93 times to 14.65%, and the brightness is increased by 1.37 times to 55 760 cd/m2. The results show that the Spiro-OMeTAD layer can effectively prevent excessive electron injection into QDs, and balance the combination of electron and hole carriers.