Single-Component Color-Tunable Gd(pic)3: Eu3+ Phosphor Based on a Metal-Organic Framework for Near-UV White-Light-Emitting Diodes

Compared with their multicomponent analogues, single-component white-light-emitting diodes (WLEDs) can eliminate the disadvantages such as high cost, fluorescence self-absorption, poor machinability, and reproducibility, but how to produce white light with high quality in a single-phase host is still a big challenge. In the work, a series of Eu3+/Tb3+-doped Gd(pic)(3) and La(pic)(3) are obtained through solvothermal conditions with picolinic acid (Hpic) and lanthanide nitrate. Researchers could regularly modulate the emitting color of phosphors by adjusting the excitation wavelength as well as the relative concentration of Ln(3+) ions to obtain white light. Different luminance values [especially quantum yield (QYs)] between host materials Gd(pic)(3) and La(pic)(3) are investigated, which shows that doping of Eu3+ into Gd(pic)(3) can improve QY to a great extent. By employing Gd0.9512Eu0.0488(pic)(3) and Gd0.9141Eu0.0451Tb0.0408(pic)(3) as phosphors, we successfully fabricated two excellent near-ultraviolet (365 nm) WLEDs with CIE chromaticity coordinates (0.3052, 0.3462) and (0.3007, 0.3448), relatively low color-correlated temperature (6755, 7001 K), and high color rendering index (R-a = 71.8, 72.9). This approach may open a new prospect for developing single-phase near-ultraviolet phosphors with high efficiency.