Octahedral Distortion Co-Regulation via Dual Strategies toward Luminescence Enhancement for the MA₄InBr₇ Perovskite Single Crystal

Abstract

A series of novel perovskite single crystals are innovatively grown. Aiming to enhance the luminescence performance, octahedral distortion coregulation via dual strategies for the as-prepared perovskite single crystals is performed. The distortion of the octahedral structure strengthens the electron− phonon coupling and electron localization, resulting in a more stable self-trapped state, which thereby increases the potential for radiative recombination, accompanied by the self-trapped exciton emission. Accordingly, the luminescence spectra of the as-prepared MA 4 In 0.975 Sb 0.025 Br 7 single crystal can cover the 450− 800 nm range, and the photoluminescence quantum yield is up to 81.25%.

Yellow-Orange Emission in Sb3+-Doped Hexakis(thiocarbamidium) Hexabromoindium(III) Tribromide

“…At the same time, a significant broadening of the excitation bands for 2 and 7 is observed with an increasing Sb 3+ content with a noticeable increase in the band at 326–327 nm. Similar trends were observed for other indium bromides doped with Sb 3+ . ,,,, …”

“…The absorption band at 380 nm may be the result of a spin-and parity-forbidden exciton transition in an isolated [InBr 6 ] 3− octahedron. 19,21,32,34,36 A similar exciton absorption band was observed for other In-based hexabromides: 360−363 nm for MA 4 InBr 7 , 34 18 and 385 nm for (PMA) 3 InBr 6 . 19 After the introduction of Sb 3+ ions into the (TUH) 6 [InBr 6 ]Br 3 lattice, characteristic parity-allowed 5s 2 → 5s5p absorption transitions of the [SbBr 6 ] 3− octahedra appear (Figures 2a and S5 and Table 3).…”

“…Such broadband emission with a large Stokes shift and fwhm is characteristic of radiative recombination of the STE state in 0D metal halides. [1][2][3][4][19][20][21]30,32,34,36,44,[46][47][48][49]51 The intrinsic emission properties of the (TUH) 6 [In 1−x Sb x Br 6 ]Br 3 crystals are confirmed by the identical photoluminescence of their powders and single crystals since the emission intensity of defectgenerated PL materials depends on the particle size and is quenched by particle aggregation. The emission of thiourea was found to be below the detection limit when excited in the range of 220−400 nm, which was also confirmed previously.…”

Regulating Exciton Diffusion in Antimony‐Based Perovskite‐Like Single Crystals toward Highly Efficient and Stable Luminescence

“…Oppositely, the [SbCl 6 ] 3− in (8-HQH)SbCl 4 causes a stronger STE effect and higher PLQY. [33,34] Figure 4c,d display the photoluminescence spectra of (8-HQ) 2 SbCl 3 and (8-HQH)SbCl 4 single crystals, respectively. The results reveal that the PL curves of the two single crystals can be composed of two emission peaks at 510 and 564 nm.…”

“…ii) The distorted metal octahedral structure and zigzag 1D metal skeleton in (8-HQH)SbCl 4 enhance the charge selftrapped effect. [16,34] iii) The full coordination of Cl − to Sb 3+ reduces the inductive effect of organic ligands and enhance the orbit hybridization between the Sb 5s 2 lone pair and the Cl 2p orbitals.…”