High luminescence efficiency white light emitting diodes based on surface functionalized quantum dots dispersed in polymer matrices

Cheolsang Yoon, Hyun Guk Hong, Hyun Chang Kim, Daehyun Hwang, Doh C. Lee, Chang Koo Kim, Young Joo Kim, Kangtaek Lee

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

We report enhancement in quantum yield of quantum dot (QD)/polydimethylsiloxane (PDMS) films via surface functionalization of CdSe/ZnS core/shell QDs. Through ligand-exchange processes, five different ligands possessing ethoxy, ester, or alkyl groups of varying chain lengths passivated the surface of QDs. In suspension, the photoluminescence quantum yield (QY) of the QDs remained relatively unaltered regardless of the ligands. On the other hand, the ligands on the surface significantly influenced the photoluminescence QY of the QD/PDMS films: QDs functionalized with the longest alkyl chain exhibited the highest QY, and QDs passivated with ester-containing group the lowest. Three-dimensional confocal microscopy revealed that spatial dispersion of QDs in the films depends on the surface ligands, and explains the QY difference. Stacking red- and green-emitting QD/PDMS films on top of blue light-emitting diodes resulted in white light emission: the longest alkyl chain-functionalized QDs gave rise to higher luminance and better color balance than unfunctionalized QDs.

Original languageEnglish
Pages (from-to)86-91
Number of pages6
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume428
DOIs
Publication statusPublished - 2013 Jul 5

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grants (No. 2011-0029118 , 2009-0082417 ) funded by the Korea government (MEST) and the Industrial Strategic Technology Development Program (No. 10035387 ) funded by the Ministry of Knowledge Economy (MKE, Korea).

All Science Journal Classification (ASJC) codes

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

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