Engineering the Electronic Structure and Optoelectronic Properties of Chiral Metal Halides through Cation Design.

The tunability of hybrid organic-inorganic metal halides through targeted chemical design is one of their most attractive features, enabling fine control over physical properties for optoelectronic applications. In chiral systems, where chirality is introduced via organic amines, this tunability is often limited by the scarcity of suitable chiral cations. In this study, we report a family of 1D lead- and tin-based chiral hybrid halides incorporating a tailor-made cation bearing both amino and hydroxyl functional groups. This chiral ligand enables the synthesis of enantiopure (S/R-AMOL)-SnI3 and (S/R-AMOL)-PbI3, where S/R-AMOL stands for (2S,2'S)-1,1'-azanediylbis-(butan-2-ol) or (2R,2'R)-1,1'-azanediylbis-(butan-2-ol). These compounds exhibit distinctive structural arrangements and bonding interactions, demonstrating effective chirality transfer through chiral centers bearing hydroxyl groups. Remarkably, substantial differences in the electronic structure and chiroptical properties are observed between the Sn and Pb analogues, including variations in emission characteristics, exciton binding energy, and orbital contributions to the electronic structure.