Chirality Extends Multiple-Channel Bistable Responses in Hybrid Perovskites

Bistable
response in various physical channels has emerged as a
key technical concept for signal processing and the encryption of
smart devices. Exploration on integrating multiple physical channels
synchronously into materials has been long envisioned and pursued,
because it can greatly enhance flexibility of information processing
and recognition and improve the expansion of the application of materials
in different fields. To achieve this end, a demanding set of material
requirements must be met and remain a great challenge. Here, we present
a pair of halide perovskite chiral enantiomers, (R-3-hydroxypyrrolium)PbBr3 and (S-3-hydroxypyrrolium)PbBr3, by implementing crystallographic engineering and chiral
strategies. Compared to their racemic counterpart, besides the significant
increase in phase-transition temperature (ΔT = 142 K), introducing homochirality enables bistable characteristics
in thermal, dielectric, ferroelasticity, photoluminescence (PL), second
harmonic generation (SHG), circular dichroism (CD), conductivity,
and photocurrent response. Compared to traditional switchable phase-transition
materials, such an unprecedented bistable response in eight channels
involving thermal, electric, mechanical, and optical aspects brings
more possibilities for sensing, smart switches, and optoelectronic
applications. This work provides new insights into constructing bistable
response materials and expanding the functional channel versatility.