Interfacial electronic structure between a W-doped In2O3 transparent electrode and a V2O5 hole injection layer for inorganic quantum-dot light-emitting diodes

Su Been Heo; Jong Hun Yu; Minju Kim; Yeonjin Yi; Ji-Eun Lee; Han-Ki Kim; Seong Jun Kang

doi:10.1039/c9ra01520e

Interfacial electronic structure between a W-doped In₂O₃ transparent electrode and a V₂O₅ hole injection layer for inorganic quantum-dot light-emitting diodes

RSC Adv. 2019 Apr 16;9(21):11996-12000. doi: 10.1039/c9ra01520e. eCollection 2019 Apr 12.

Authors

Su Been Heo¹, Jong Hun Yu¹, Minju Kim², Yeonjin Yi², Ji-Eun Lee³, Han-Ki Kim³, Seong Jun Kang¹

Affiliations

¹ Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University 1732 Deogyeong-daero, Giheung-gu Yongin Gyeonggi-do 17104 Republic of Korea [email protected] +82-31-201-3324.
² Institute of Physics and Applied Physics, Yonsei University 50 Yonsei-ro, Seodaemun-gu Seoul 03722 Republic of Korea.
³ School of Advanced Materials & Engineering, Sungkyunkwan University 2066 Seobu-ro, Jangan-gu Suwon Gyeonggi-do 16419 Republic of Korea.

Abstract

The interfacial electronic structure between a W-doped In₂O₃ (IWO) transparent electrode and a V₂O₅ hole injection layer (HIL) has been investigated using ultraviolet photoelectron spectroscopy for high-performance and inorganic quantum-dot light-emitting diodes (QLEDs). Based on the interfacial electronic structure measurements, we found gap states in a V₂O₅ HIL at 1.0 eV below the Fermi level. Holes can be efficiently injected from the IWO electrode into poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(4-sec-butylphenyl)diphenylamine)] (TFB) through the gap states of V₂O₅, which was confirmed by the hole injection characteristics of a hole-only device. Therefore, conventional normal-structured QLEDs were fabricated on a glass substrate with the IWO transparent electrode and V₂O₅ HIL. The maximum luminance of the device was measured as 9443.5 cd m^-2. Our result suggests that the IWO electrode and V₂O₅ HIL are a good combination for developing high-performance and inorganic QLEDs.