Bi3+/Te4+ Co-Doping Achieves Dual-Band-Tunable White-Light Emission in Perovskite-Derivative Microcrystals

The Bi³⁺ and Te⁴⁺ ions in singly-doped MCs exhibited intense blue and yellow PL originating from the inter-configurational ³P_0,1→¹S₀ transitions at 456 and 565 nm with large Stokes shifts, broad emission bands, and high PL quantum yields (QYs) of 60.6% and 84.6%, respectively, due to strong electron-phonon coupling in the spatially confined 0D structure of Cs₂SnCl₆.

Due to the strong temperature dependence of the spin-forbidden ³P₀→¹S₀ and spin-orbital allowed ³P₁→¹S₀ transitions of Bi³⁺, the authors discovered a spectacular transition in the PL lifetime from 1.20 ms at 10 K to 1.49 μs at 300 K in Cs₂SnCl₆: 1.1% Bi³⁺, as solid evidence for the isolated Bi³⁺ emission.

Furthermore, they achieved dual-band-tunable white-light emissions in Cs₂SnCl₆: Bi³⁺/Te⁴⁺MCs with excellent structure-, air-, photo- and anti-water stability and a PLQY of up to 68.3% through efficient ET from Bi³⁺ to Te⁴⁺.

This research adds to the understanding of Bi³⁺ and Te⁴⁺ excited-state dynamics in Cs₂SnCl₆, as well as a general approach to achieving single-composition white-light emitters based on lead-free metal halides using ns²-metal ion co-doping.

Journal Reference:

Zhang, W., et al. (2022) Dual-Band-Tunable White-Light Emission from Bi³⁺/Te⁴⁺ Emitters in Perovskite-Derivative Cs₂SnCl₆ Microcrystals. Angewandte Chemie International Edition. doi.org/10.1002/anie.202116085.