Organometallic-Based Hybrid Perovskite Piezoelectrics with a Narrow Band Gap

Hybrid organic–inorganic
perovskites (HOIPs) with the general formula ABX3 hold
phenomenal research interest for their great scientific and technological
potential in photovoltaic, piezoelectric, and electroluminescent devices.
It is their considerable structural diversity that offers a good opportunity
to build a variety of HOIP structures with various functionalities.
However, no organometallic-based HOIP piezoelectrics have yet been
found, despite the structural diversity and functional richness of
organometallic compounds such as the ferrocene-based family. Here,
for the first time, we report an organometallic-based HOIP piezoelectric,
[(ferro­cenyl­methyl)­tri­methyl­ammonium]­PbI3. Benefitting from the stability of ferrocene-based cations,
excellent piezoelectric performance, comparable to that of LiNbO3, can be obtained and optimized by tuning the anionic framework.
The involvement of organometallic cations enables a narrow band gap
of 2.37 eV, much lower than those of most HOIPs and some inorganic
semiconductors. This work provides a new future direction for the
study of perovskites and will inspire intriguing research on organometallic-based
HOIP piezoelectrics.