Spectrally flat white light emission based on red-yellow-green-blue dye-loaded metal-organic frameworks

Abstract

We realize a white light emission based on metal-organic frameworks (MOFs), which are loaded with red/yellow/green/blue (R/Y/G/B) primary-colour fluorescent dye molecules. The MOF⊃dye powders emitting red/green/blue light are synthesized via an activated adsorption reaction, whilst the MOF⊃dye powder emitting yellow light is prepared via an in-situ reaction. By grinding these R/Y/G/B MOF⊃dye powders and adjusting the mass proportions of each primary-colour component, a white light emission with a quasi-flat spectrum is obtained. Experimentally, under excitation with an ultraviolet light (at a wavelength of 365 nm), the emission peaks of the R/Y/G/B MOF⊃dye powders are located at 621.0 nm, 560.0 nm, 522.5 nm and 438.5 nm, respectively. When the mass proportions of R/Y/G/B components are 35.3%, 21.2%, 14.7% and 28.8%, the full-width at half-maximum bandwidth of the light emission is 251.5 nm (from 391.5 nm to 643.0 nm), and the 1-dB bandwidth is 201.5 nm. The measured Commission Internationale de L'Eclairage (CIE) coordinates are (0.319, 0.341). The flat and wide spectrum of this material makes it a promising candidate in applications such as lighting, display and visible-light communication systems.