Efficient exciton generation in atomic passivated CdSe/ZnS quantum dots light-emitting devices

Byoung-Ho Kang; Jae-Sung Lee; Sang-Won Lee; Sae-Wan Kim; Jun-Woo Lee; Sai-Anand Gopalan; Ji-Sub Park; Dae-Hyuk Kwon; Jin-Hyuk Bae; Hak-Rin Kim; Shin-Won Kang

doi:10.1038/srep34659

Efficient exciton generation in atomic passivated CdSe/ZnS quantum dots light-emitting devices

Sci Rep. 2016 Sep 30:6:34659. doi: 10.1038/srep34659.

Authors

Affiliations

¹ Center for Functional Devices Fusion Platform, Kyungpook National University, Sankyuk-dong, Bukgu, 702-701 Daegu, Republic of Korea.
² School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Sankyuk-dong, Bukgu, 702-701 Daegu, Republic of Korea.
³ Department of Electronic Engineering, Kyungil University, Buho-ri, Hayang-eup, 712-701 Gyeongsan-si, Republic of Korea.

Abstract

We demonstrate the first-ever surface modification of green CdSe/ZnS quantum dots (QDs) using bromide anions (Br^-) in cetyl trimethylammonium bromide (CTAB). The Br^- ions reduced the interparticle spacing between the QDs and induced an effective charge balance in QD light-emitting devices (QLEDs). The fabricated QLEDs exhibited efficient charge injection because of the reduced emission quenching effect and their enhanced thin film morphology. As a result, they exhibited a maximum luminance of 71,000 cd/m² and an external current efficiency of 6.4 cd/A, both significantly better than those of their counterparts with oleic acid surface ligands. In addition, the lifetime of the Br- treated QD based QLEDs is significantly improved due to ionic passivation at the QDs surface.