Wide gamut white LED device using green CsPbBr3 quantum dots glass and red K2SiF6: Mn4+ phosphor

Abstract

Wide gamut white LED device is fabricated by combining green CsPbBr3 quantum dots glass (QDG) and red K2SiF6: Mn4+ phosphor with blue LED. The green CsPbBr3 QDG shows steep absorption spectra, narrow and symmetrical photoluminescence (PL) spectra, broad band excitation spectra and bi-exponential fluorescence decay. PL peak, full width at half maximum and average lifetime are 515 nm, 18 nm and 94.9 ns respectively. The red K2SiF6: Mn4+ phosphor shows narrow red emission peaks of Mn4+, broad excitation peaks, and single exponential fluorescence decay with lifetime of 8.5 ms. The green CsPbBr3 QDG has strong temperature dependence of PL intensity. The red K2SiF6: Mn4+ phosphor has negligible temperature dependence. The white LED device has wide color gamut of 134% NTSC and high color purity of 98%, 89% and 99% for the blue, green and red lights. The white light of white LED device has been realized by controlling thickness of the green CsPbBr3 QDG and content of the red K2SiF6: Mn4+ phosphor. We have evaluated the chromatic coordinate stability at different operating powers and times, and the maximum chromatic changes are as small as (0.004, 0.012) and (0.009, 0.026) for (x, y) respectively in CIE 1931 (Commission International de l′Eclairage 1931) chromatic coordinate.