Search

Cs2SnCl6 double perovskite has attracted wide attention as a promising optoelectronic material because of its better stability and lower toxicity than its lead counterparts. However, pure Cs2SnCl6 demonstrates quite poor optical properties, which usually calls for active element doping to realize efficient luminescence. Herein, a facile co-precipitation method was used to synthesize Te4+ and Er3+-co-doped Cs2SnCl6 microcrystals. The prepared microcrystals were polyhedral, with a size distribution around 1–3 μm. Highly efficient NIR emissions at 1540 nm and 1562 nm due to Er3+ were achieved in doped Cs2SnCl6 compounds for the first time. Moreover, the visible luminescence lifetimes of Te4+/Er3+-co-doped Cs2SnCl6 decreased with the increase in the Er3+ concentration due to the increasing energy transfer efficiency. The strong and multi-wavelength NIR luminescence of Te4+/Er3+-co-doped Cs2SnCl6 originates from the 4f→4f transition of Er3+, which was sensitized by the spin-orbital allowed 1S0→3P1 transition of Te4+ through a self-trapped exciton (STE) state. The findings suggest that ns2-metal and lanthanide ion co-doping is a promising method to extend the emission range of Cs2SnCl6 materials to the NIR region. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continuous synthesis of Cs x Pb y Br z NCs were realized via a microfluidic system. • Cs x Pb y Br z perovskite NCs with tunable dimensionalities were achieved. • Stable CsPbBr 3 /Cs 4 PbBr 6 composite NCs exhibited bright emissions in solid forms. • Growth and luminescence mechanisms of Cs x Pb y Br z perovskite NCs were revealed. All-inorganic perovskite CsPbBr 3 shows great potential in optoelectronic device applications due to their excellent optoelectrical properties. However, its practical use is still dauntingly plagued by the poor stability. Recently, its derivatives Cs 4 PbBr 6 and CsPb 2 Br 5 featured with good stability and the versatility in crystal structure have emerged as promising alternatives. Nevertheless, synthesizing such a series of perovskites through a facile, scalable, and high-yield method is challenging, and their luminescence mechanisms are still elusive. Herein, we reported a facile and rapid method for continuous synthesis of Cs x Pb y Br z -based perovskites (including Cs 4 PbBr 6 , CsPbBr 3 /Cs 4 PbBr 6 , CsPbBr 3 , CsPbBr 3 /CsPb 2 Br 5 , CsPb 2 Br 5) via a microfluidic system. The transformations of different dimensional perovskite nanocrystals were realized by simply adjusting the precursor flow rate. CsPbBr 3 /Cs 4 PbBr 6 and CsPbBr 3 /CsPb 2 Br 5 composite nanocrystals exhibited bright emissions in their solid forms, where CsPbBr 3 nanocrystals uniformly embedded in Cs 4 PbBr 6 or CsPb 2 Br 5 matrix. Simultaneously, strong green fluorescence exclusively from CsPbBr 3 nanocrystals was detected and related energy transfer in composite nanocrystals was further investigated. Finally, the highly stable CsPbBr 3 /Cs 4 PbBr 6 nanocrystals were used for the construction of WLED with a wide color gamut of 131% NTSC. This work provides a novel path for large-scale and controlled synthesis of the ternary Cs-Pb-Br materials for specific light-emitting applications. [ABSTRACT FROM AUTHOR]