Zero-dimensional hybrid Cu(I) halide with cyan light emission for use in white light emitting diode

Traditional white light-emitting diode (WLED) is mainly depending on coating broadband yellow phosphors (520–700 nm) on blue emitting LED chip (440–460). However, too strong blue light and absence of cyan light results in incongruous emission strength and low color rendering index (CRI), which cause serious damage to retina of eye. To overcome these shortcomings, cyan light emitting phosphor is highly desirable for the full-visible-spectrum LED with high CRI, but bright cyan phosphor remains rare. Herein, a new 0D hybrid copper(I) halide of [TMPDA]CuI (TMPDA = ,2,2-tetramethyl-1,3-propylenediamine) single crystal is reported as a cyan light emitter with mominant emission wavelength at 489 nm, photoluminescence quantum yield of 26.66 % and large Stokes shift of 198 nm exceeding most of organic-inorganic metal halides. Remarkably, the single crystals display stable emission in various polar organic solvents and high temperature with sufficient emitting stability. More significantly, this 0D cuprous halide act as down-conversion cyan phosphor to fabricate WLED with a high CRI of 95 by reducing the cyan gap. In this study, we demonstrate an optical engineering strategy to prepare efficient cyan light emitting 0D cuprous halide and assembly high-performance WLED.