posted on 2023-11-22, 10:29authored byYan-Ran Weng, Feng Zhou, Yu Shi, Shu-Yu Tang, Hui-Peng Lv, Meng-Juan Yang, Yuan-Yuan Tang, Yong Ai
Organic–inorganic
hybrid perovskites (OIHPs) have been emerging
as a hot research topic due to their potential applications in energy
storage, semiconductors, and electronic devices. Herein, we systematically
investigated the synthesis and phase transition behaviors of the enantiomeric
OIHPs, (R) and (S)–N,N-dimethyl-3-fluoropyrrolidinium cadmium
bromide ([DMFP][CdBr3]), and the hybrid trigonal structure
[DMFP]3 (CdBr3)(CdBr4). The enantiomers
have a mirror-symmetric structure and enhanced solid-state phase transition
points of 417 and 443 K, in contrast to the nonfluorinated parent
compound, N,N-dimethyl-pyrrolidinium
cadmium bromide ([DMP][CdBr3], 385 K). Moreover, racemic
H/F substitution on the pyrrolidinium cations leads to the formation
of a trigonal compound, showing above-room-temperature structural
phase transition and dominant ferroelasticity. This work discovers
chiral enantiomeric OIHPs through H/F substitution, demonstrating
a useful chemical synthesis strategy for exploring novel phase transition
materials.