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1. Photo-induced halide redistribution in 2D halide perovskite lateral heterostructures

   https://doi.org/10.1016/j.joule.2023.08.003  

   Luo, Yanqi; Zhang, Shuchen; Chen, Jia-Shiang; Ma, Xuedan; Ma, Ke; Deng, Junjing; Jiang, Yi; Li, Luxi; Lai, Barry; Chen, Si; et al (October 2023, Joule)
2. Studying Hydrogen–Halide Interactions in Lead Halide Perovskite with Isoelectronic Cations

   https://doi.org/10.1021/acs.chemmater.3c01149  

   Huang, Yunping; Shi, Yangwei; Cohen, Theodore A.; Ho, Kevin; Luscombe, Christine K. (October 2023, Chemistry of Materials)
3. Polymorphism in metal halide perovskites

   https://doi.org/10.1039/D0MA00643B  

   Alaei, Aida; Circelli, Abigail; Yuan, Yihang; Yang, Yi; Lee, Stephanie S. (January 2021, Materials Advances)

   null (Ed.)

   Metal halide perovskites (MHPs) are frontrunners among solution-processable materials for lightweight, large-area and flexible optoelectronics. These materials, with the general chemical formula AMX 3 , are structurally complex, undergoing multiple polymorph transitions as a function of temperature and pressure. In this review, we provide a detailed overview of polymorphism in three-dimensional MHPs as a function of composition, with A = Cs + , MA + , or FA + , M = Pb 2+ or Sn 2+ , and X = Cl − , Br − , or I − . In general, perovskites adopt a highly symmetric cubic structure at elevated temperatures. With decreasing temperatures, the corner-sharing MX 6 octahedra tilt with respect to one another, resulting in multiple polymorph transitions to lower-symmetry tetragonal and orthorhombic structures. The temperatures at which these phase transitions occur can be tuned via different strategies, including crystal size reduction, confinement in scaffolds and (de-)pressurization. As discussed in the final section of this review, these solid-state phase transformations can significantly affect optoelectronic properties. Understanding factors governing these transitions is thus critical to the development of high-performance, stable devices. 

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4. Atomistic Mechanism of Passivation of Halide Vacancies in Lead Halide Perovskites by Alkali Ions

   https://doi.org/10.1021/acs.chemmater.0c04188  

   Li, Wei; Zhan, Juan; Liu, Xiaorui; Tang, Jianfeng; Yin, Wan-Jian; Prezhdo, Oleg V. (February 2021, Chemistry of Materials)

   null (Ed.)
5. Barocaloric Effects in Dialkylammonium Halide Salts

   https://doi.org/10.1021/jacs.3c12402  

   Seo, Jinyoung; Ukani, Rahil; Zheng, Juanjuan; Braun, Jason D.; Wang, Sicheng; Chen, Faith E.; Kim, Hong Ki; Zhang, Selena; Thai, Catherine; McGillicuddy, Ryan D.; et al (January 2024, Journal of the American Chemical Society)

   Barocaloric effects─solid-state thermal changes induced by the application and removal of hydrostatic pressure─offer the potential for energy-efficient heating and cooling without relying on volatile refrigerants. Here, we report that dialkylammonium halides─organic salts featuring bilayers of alkyl chains templated through hydrogen bonds to halide anions─display large, reversible, and tunable barocaloric effects near ambient temperature. The conformational flexibility and soft nature of the weakly confined hydrocarbons give rise to order–disorder phase transitions in the solid state that are associated with substantial entropy changes (>200 J kg–1 K–1) and high sensitivity to pressure (>24 K kbar–1), the combination of which drives strong barocaloric effects at relatively low pressures. Through high-pressure calorimetry, X-ray diffraction, and Raman spectroscopy, we investigate the structural factors that influence pressure-induced phase transitions of select dialkylammonium halides and evaluate the magnitude and reversibility of their barocaloric effects. Furthermore, we characterize the cyclability of thin-film samples under aggressive conditions (heating rate of 3500 K s–1 and over 11,000 cycles) using nanocalorimetry. Taken together, these results establish dialkylammonium halides as a promising class of pressure-responsive thermal materials. 

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