Hasan Md Mehedi, Khan Mithun, Afsuddin Md, Ali Md Lokman
Department of Physics, Pabna University of Science and Technology, Pabna, 6600, Bangladesh.
Heliyon. 2024 Oct 16;10(20):e39285. doi: 10.1016/j.heliyon.2024.e39285. eCollection 2024 Oct 30.
This research employs first-principles simulations to systematically study the structural, elastic, electronic mechanical, and optical characteristics of lead free halide RbAgBiX (X = Br, Cl) perovskites under pressure. The computed structural parameters are in good agreement with previous experimental and theoretical results. The obtained elastic constants met the Born stability requirements, showing that our materials are mechanically stable at variable hydrostatic pressures, as supported by the computed negative formation energy values. The covalent bond exhibits metallic characteristics, and induced hydrostatic pressure leads to a decrease in bond lengths. Mechanical analysis demonstrates that the studied materials are ductile and mechanically stable, with enhanced ductility under pressure. The materials are small band gap (1.30 eV, 1.801 eV for RbAgBiX (X = Br, Cl, respectively) semiconductors at ambient pressure with superior optoelectronic performance. Under hydrostatic pressure, RbAgBiX (X = Br, Cl) experiences a reduction in its band gap (0.545 eV, 1.305 eV for RbAgBiX (X = Br, Cl, respectively), accompanied by improved physical characteristics. This suggests the potential for increased utilization of this material in optoelectronic devices and solar cells compared to ambient pressure conditions.
本研究采用第一性原理模拟系统地研究了无铅卤化物RbAgBiX（X = Br、Cl）钙钛矿在压力下的结构、弹性、电子力学和光学特性。计算得到的结构参数与先前的实验和理论结果吻合良好。所获得的弹性常数满足玻恩稳定性要求，这表明我们的材料在可变静水压力下是机械稳定的，计算得到的负形成能值也支持了这一点。共价键表现出金属特性，外加静水压力导致键长减小。力学分析表明，所研究的材料具有延展性且机械稳定，在压力下延展性增强。这些材料是小带隙半导体（在常压下，RbAgBiX（X = Br、Cl）的带隙分别为1.30 eV、1.801 eV），具有优异的光电性能。在静水压力下，RbAgBiX（X = Br、Cl）的带隙减小（RbAgBiX（X = Br、Cl）分别为0.545 eV、1.305 eV），同时物理特性得到改善。这表明与常压条件相比，该材料在光电器件和太阳能电池中的应用潜力有所增加。
