Roy Mrinmoy, Dedhia Urvi, Alam Aftab, Aslam M
Department of Physics, Indian Institute of Technology Bombay, Mumbai, India 400076.
Materials Modelling Group, Department of Physics, Indian Institute of Technology Bombay, Mumbai, India 400076.
J Phys Chem Lett. 2021 Feb 4;12(4):1189-1194. doi: 10.1021/acs.jpclett.0c03426. Epub 2021 Jan 22.
We present a simple yet powerful synthesis process to prepare compound-phase perovskite nanoparticles (MAPbXY; MA = CHNH and X/Y = I, Br, or Cl). This is achieved by mixing two pure-phase perovskites (MAPbX and MAPbY) by using ultrasonic vibration as a mechanochemical excitation. Unlike conventional methods, this procedure does not require any effort in designing a reaction or choosing any particular precursor. X-ray diffraction and TEM studies confirm compound-phase formation in all possible stoichiometries. The origin behind ultrasonic mixing lies in the generation of mechanical stress and high temperature arising from acoustic cavitation during reaction. Long-term experimental stability of the compound-phase is comprehended theoretically by simulating the temperature-dependent Gibbs free energy. Negative mixing entropy plays a crucial role during the synthesis which leads to better stabilization of the compound-phase perovskite over the pure-phase. The ease of synthesis and remarkable phase stability make this process effective and less cumbersome for perovskite nanoparticle synthesis.
我们提出了一种简单而强大的合成方法来制备复合相钙钛矿纳米颗粒（MAPbXY；MA = CHNH 且 X/Y = I、Br 或 Cl）。这是通过使用超声振动作为机械化学激发来混合两种纯相钙钛矿（MAPbX 和 MAPbY）实现的。与传统方法不同，该过程在设计反应或选择任何特定前驱体方面无需任何努力。X 射线衍射和透射电子显微镜研究证实了所有可能化学计量比下复合相的形成。超声混合背后的原理在于反应过程中声空化产生的机械应力和高温。通过模拟温度依赖的吉布斯自由能从理论上理解了复合相的长期实验稳定性。负混合熵在合成过程中起着关键作用，这导致复合相钙钛矿比纯相具有更好的稳定性。合成的简便性和显著的相稳定性使得该过程对于钙钛矿纳米颗粒的合成有效且不那么繁琐。
