White light-emitting diodes of high color rendering index with polymer dot phosphors

Abstract

Nowadays the yellow emissive YAG:Ce phosphors play an important role in fabricating white light-emitting diodes (WLEDs). However, they are deficient in red emission so we proposed polymer dot phosphors to compensate this poor photometric property. The polymer dot phosphors exhibited broad emission bands under excitation of a blue LED chip with weak reabsorption. We demonstrated hybrid white light-emitting diodes with commendable color rendering index (85–95), widely variable color temperatures (3050–7295 K) and high luminous efficacy (72–80 lm W⁻¹ operated at 20 mA) by combining green and red emitting polymer dots on YAG:Ce-based WLEDs. The optical properties suggest the polymer dot phosphors are the suitable color converting materials, which may enable their application in WLED lighting.