Tuning exciton binding and photoabsorption in vacancy-ordered halide double perovskites Rb2ZrX6 (X = Cl, Br, I)

IF 3.6 2区物理与天体物理 Q2 PHYSICS, APPLIED

Applied Physics Letters Pub Date : 2025-10-13 DOI:10.1063/5.0281038

Il-Chol Ri, Myong Choe, Suk-Gyong Hwang, Chol-Jun Yu

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引用次数: 0

Abstract

Vacancy-ordered halide double perovskites (VHDPs) have emerged as a promising candidate for broadband luminescence, but the underlying mechanism remains obscure. Here, we report a study of quasiparticle band structures and excitonic properties under the lattice strain of Rb2ZrX6 (X = Cl, Br, I) using G0W0 plus the Bethe–Salpeter equation calculations. Our calculations demonstrate that cubic Rb2ZrX6 have direct bandgaps and large effective masses of electrons and holes, which become smaller for larger halogens. Through the analysis of the photoabsorption spectra, we identify bright and dark excitons blueshifted for smaller halogens, finding a bright exciton at 4.96 eV in agreement with the experimental optical bandgap for Rb2ZrCl6. We find an extremely large exciton binding energy of 1.17 eV for chloride but a much smaller value of 0.22 eV for iodide. Furthermore, compressive strain reduces bandgaps, effective masses, and exciton binding energies, but tensile strain causes an inverse effect, while both strains enhance photoabsorption. Our work highlights an important role of halogen substitution and lattice strain in tuning the optoelectronic properties of VHDPs.

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空位有序卤化物双钙钛矿Rb2ZrX6 （X = Cl, Br， I）的激子结合和光吸收调谐

空位有序卤化物双钙钛矿（VHDPs）已成为宽带发光的有前途的候选材料，但其潜在的机制尚不清楚。本文用G0W0和Bethe-Salpeter方程计算了Rb2ZrX6 （X = Cl, Br， I）晶格应变下的准粒子带结构和激子性质。我们的计算表明，立方Rb2ZrX6具有直接带隙和较大的有效电子和空穴质量，对于较大的卤素来说，有效电子和空穴质量变小。通过光吸收光谱分析，我们发现了小卤素蓝移的亮激子和暗激子，在4.96 eV处发现了一个与Rb2ZrCl6实验光带隙一致的亮激子。我们发现氯离子的激子结合能非常大，为1.17 eV，而碘离子的激子结合能要小得多，为0.22 eV。此外，压缩应变降低了带隙、有效质量和激子结合能，而拉伸应变则相反，而两种应变都增强了光吸收。我们的工作强调了卤素取代和晶格应变在调整VHDPs光电特性中的重要作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Physics Letters 物理-物理：应用

CiteScore

6.40

自引率

10.00%

发文量

1821

审稿时长

1.6 months

期刊介绍： Applied Physics Letters (APL) features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, APL offers prompt publication of new experimental and theoretical papers reporting applications of physics phenomena to all branches of science, engineering, and modern technology. In addition to regular articles, the journal also publishes invited Fast Track, Perspectives, and in-depth Editorials which report on cutting-edge areas in applied physics. APL Perspectives are forward-looking invited letters which highlight recent developments or discoveries. Emphasis is placed on very recent developments, potentially disruptive technologies, open questions and possible solutions. They also include a mini-roadmap detailing where the community should direct efforts in order for the phenomena to be viable for application and the challenges associated with meeting that performance threshold. Perspectives are characterized by personal viewpoints and opinions of recognized experts in the field. Fast Track articles are invited original research articles that report results that are particularly novel and important or provide a significant advancement in an emerging field. Because of the urgency and scientific importance of the work, the peer review process is accelerated. If, during the review process, it becomes apparent that the paper does not meet the Fast Track criterion, it is returned to a normal track.