ADVANCED OPTICAL MATERIALS.27 April 2023.https://doi.org/10.1002/adom.202300218

Organic–inorganic metal halides (OIMHs) with high-efficiency solar spectrum-like emission are attracting broad and current interest. Here, five 0D Zn-based hybrid halides are synthesized based on aromatic organic cations with different carbon-chain lengths: C₆H₅CH₂NH₃⁺ (PMA⁺) and C₆H₅(CH₂)₄NH₃⁺ (PBA⁺). (PMA)₂ZnCl₄ exhibits the highest photoluminescence quantum yield of 37.2% of reported Zn-based white-emission OIMHs. The emission spectrum of (PBA)₂ZnI₄ indicates a color rendering index of 98, which is the highest among single-component white-light-emitting phosphors. Spectral characterizations and density functional theory calculations demonstrate that the extremely broad emission of (PBA)₂ZnI₄ originates from the synergistic emission of organic cations and self-trapped excitons. The optical properties of the obtained (PMA)₂ZnBr₄, (PMA)₂ZnI₄·H₂O, and (PBA)₂ZnCl₄ are also characterized for comparison, and with the same organic cations, the PLQY decreases from chloride to bromide to iodide. This work demonstrates that the selection of appropriate organics and halogens can enable fine tuning of single-component white-light emission, satisfying varying needs for solid-state lighting.

Inorg. Chem. Front., 2023,10, 2430-2437.https://pubs.rsc.org/en/content/articlelanding/2023/QI/D2QI02489F

With the pursuit of healthy lighting, full-spectrum white light-emitting diodes (WLEDs) fabricated with violet chips and tri-color phosphors have been put forward. However, the excitation bands of most reported blue phosphors are located in the ultraviolet (UV) region, which hinders the development of full-spectrum lighting. In this work, by partially introducing N³⁻ into a matrix, a series of Ba_0.697Al_10.914O_17.232-3y/2N_y:0.16Eu²⁺ (BAON_y:Eu) blue phosphors with red-shifted photoluminescence excitation (PLE) spectra were synthesized. Under the excitation of 400 nm violet light, the internal/external quantum efficiency (IQE/EQE) values of the optimal sample BAON_1.0:Eu were calculated to be 80%/52%, while the retained integrated emission intensity at 150 °C can be 95% of that at room temperature. The WLED device fabricated by coating BAON_1.0:Eu and other commercial phosphors on a violet chip achieved an ultra-high color rendering index (R_a = 95.4). These results indicate that our synthesized BAON_1.0:Eu can be an excellent candidate blue phosphor for full-spectrum WLED lighting.