Reduced graphene oxide enwrapped phosphors for long-term thermally stable phosphor converted white light emitting diodes

Gopinathan Anoop, Janardhanan R. Rani, Juhwan Lim, Myoung Soo Jang, Dong Wook Suh, Shinill Kang, Seong Chan Jun, Jae Soo Yoo

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The long-term instability of the presently available best commercial phosphor-converted light-emitting diodes (pcLEDs) is the most serious obstacle for the realization of low-cost and energy-saving lighting applications. Emission from pcLEDs starts to degrade after approximately 200 h of operation because of thermal degradation of the phosphors. We propose a new strategy to overcome this thermal degradation problem of phosphors by wrapping the phosphor particles with reduced graphene oxide (rGO). Through the rGO wrapping, we have succeeded in controlling the thermal degradation of phosphors and improving the stability of fabricated pcLEDs. We have fabricated pcLEDs with long-term stability that maintain nearly 98% of their initial luminescence emission intensity even after 800 h of continuous operation at 85 °C and 85% relative humidity. The pcLEDs fabricated using SrBaSi 2 O 2 N 2:Eu 2+ phosphor particles wrapped with reduced graphene oxide are thermally stable because of enhanced heat dissipation that prevents the ionization of Eu 2+ to Eu 3+. We believe that this technique can be applied to other rare-earth doped phosphors for the realization of highly efficient and stable white LEDs.

Original languageEnglish
Article number33993
JournalScientific reports
Volume6
DOIs
Publication statusPublished - 2016 Sep 27

All Science Journal Classification (ASJC) codes

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