Optically Modulated Ultra-Broad-Band Warm White Emission in Mn2+-Doped (C6H18N2O2)PbBr4 Hybrid Metal Halide Phosphor

Chem. Mater., 2019, 31, 15, 5788–5795. https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.9b01864

Finding new low-dimensional metal halides with broad-band emission is attracting interest in single-component phosphor for white light-emitting diodes (WLEDs). The full-spectrum white light still remains a challenge as found in the two-dimensional hybrid material (C6H18N2O2)PbBr4 exhibiting the intrinsic free exciton (FE) and broad-band self-trap exciton (STE) emission upon 365 nm ultraviolet excitation, and a combined strategy has been proposed through doping the Mn2+ ions enabling a superposition of multiple emission centers toward the ultra-broad-band warm white light. The occupation of Mn2+ in (C6H18N2O2)PbBr4 has been discussed, and optical investigations verify that the warm white-light emission of Mn2+-doped (C6H18N2O2)PbBr4 originates from the coupling effects of the FE, STEs, and the 4T16A1 transition of the doped Mn2+. When the concentration of Mn2+ is 5%, the emission spectrum of the phosphor covers all visible-light areas with a full width at half maximum (FWHM) of about 230 nm. The high Ra (84.9) and warm light CCT (3577 K) values of the as-fabricated WLED lamp demonstrate that (C6H18N2O2)Pb1–xMnxBr4 can be promising as single-component white-light phosphor in solid-state lighting. Our work could provide a new understanding and perspective about hybrid metal halides for designing superior phosphor toward single-component white emission.

Manipulation of Bi3+/In3+ Transmutation and Mn2+‐Doping Effect on the Structure and Optical Properties of Double Perovskite Cs2NaBi1‐xInxCl6


The halide double perovskite family represented by A2(B+,B3+)X6 can overcome the lead toxicity and enable generally large band gap engineering via B/B sites’ transmutation or exotic dopants to fulfill the emerging applications in the optoelectronic fields. Herein, the design and the experimental synthesis of a new family of Mn2+-doped Cs2NaBi1-xInxCl6 crystals with an intense orange-yellow emission band are reported, and the phase formation stability is discussed via a combined experimental–theoretical approach. Depending on the manipulation of Bi3+/In3+ combination, the band gap increases with In3+ content, and a subsequent evolution from indirect to direct band gap is verified. First-principles calculations and parity analyses indicate a parity forbidden effect on Cs2NaInCl6, and a combination effect of absorption on Cs2NaBi1-xInxCl6 from both Cs2NaBiCl6 and Cs2NaInCl6. The associated Mn2+-doped photoluminescence depending on the Bi3+/In3+ substitution is also addressed from the variation of the different Mn–Cl environment and neighboring-cation effect.