Singh Akash, Jana Manoj K, Mitzi David B
Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA.
Department of Chemistry, Duke University, Durham, NC, 27708, USA.
Adv Mater. 2021 Jan;33(3):e2005868. doi: 10.1002/adma.202005868. Epub 2020 Dec 6.
Crystalline metal halide perovskites (MHPs) have provided unprecedented advances in interdisciplinary fields of materials, electronics, and photonics. While crystallinity offers numerous advantages, the ability to access a glassy state with distinct properties provides unique opportunities to extend the associated structure-property relationship, as well as broaden the application space for MHPs. Amorphous analogs for MHPs have so far been restricted to high pressures, limiting detailed studies and applications. Here, a 2D MHP is structurally tailored using bulky chiral organic cations to exhibit an unusual confluence of exceptionally low melting temperature (175 °C) and inhibited crystallization. The chiral MHP can thus be melt-quenched into a stable glassy state, otherwise inhibited in the analogous racemic MHP. Facile and reversible switching between glassy and crystalline states is demonstrated for the chiral MHP, each with distinct optoelectronic character, opening new opportunities for applications including, for example nonvolatile memory, optical communication, and neuromorphic computing.
晶体金属卤化物钙钛矿（MHP）在材料、电子和光子学等跨学科领域取得了前所未有的进展。虽然结晶性具有诸多优势，但获得具有独特性质的玻璃态的能力为扩展相关的结构-性质关系以及拓宽MHP的应用空间提供了独特机遇。到目前为止，MHP的非晶类似物仅限于高压条件，这限制了详细的研究和应用。在此，使用体积较大的手性有机阳离子对二维MHP进行结构定制，使其呈现出异常低的熔点（175°C）和抑制结晶的异常融合。因此，手性MHP可以通过熔体淬火形成稳定的玻璃态，而在类似的外消旋MHP中则会受到抑制。手性MHP展示了在玻璃态和结晶态之间的便捷且可逆的转变，每种状态都具有独特的光电特性，为包括非易失性存储器、光通信和神经形态计算等在内的应用开辟了新机遇。
