[Paper] Green Electroluminescence Generated by Band-edge Transition in Ag-In-Ga-S/GaSx Core/shell Quantum Dots

Genichi Motomura; Yukiko Iwasaki; Tatsuya Kameyama; Tsukasa Torimoto; Taro Uematsu; Susumu Kuwabata; Toshimitsu Tsuzuki

doi:10.3169/mta.9.222

Special Section on IDW '20

[Paper] Green Electroluminescence Generated by Band-edge Transition in Ag-In-Ga-S/GaS_x Core/shell Quantum Dots

Genichi Motomura, Yukiko Iwasaki, Tatsuya Kameyama, Tsukasa Torimoto, Taro Uematsu, Susumu Kuwabata, Toshimitsu Tsuzuki

Author information

Keywords: Quantum dot, Light-emitting diode, Electroluminescence, Band edge emission, Defect emission, Chalcopyrite-type QD

JOURNAL FREE ACCESS

2021 Volume 9 Issue 4 Pages 222-227

DOI https://doi.org/10.3169/mta.9.222

Details

Abstract

Quantum-dot light-emitting diodes (QD-LEDs) that exhibit green emission were fabricated using Ag-In-Ga-S/GaS_x (AIGS) core/shell QDs as low-toxicity QDs. Although multi-element QDs such as AIGS are prone to broad-wavelength defect-induced emission, the core/shell structure enables sharp emission from band-edge transitions. The electroluminescence (EL) spectra were found to include a large defect emission component compared with the photoluminescence spectra of the QD films because of the difference in the excitation process of the QDs. The defect emission was attributed to the electrons injected into the emitting layer (EML) being easily trapped at the defect sites in the QDs. The addition of an electron transporting material to the EML effectively blocked the direct injection route and reduced the electron trapping at the defect sites. Consequently, the color purity of the EL emission was enhanced and the QD-LEDs exhibited green EL emission.

Corresponding author

Register with J-STAGE for free!