Chiral Lead Halide Perovskite Nanowires for Second-Order Nonlinear Optics

Hybrid organic/inorganic
lead halide perovskites (LHPs) have recently
emerged as extremely promising photonic materials. However, the exploration
of their optical nonlinearities has been mainly focused on the third-
and higher-order nonlinear optical (NLO) effects. Strong second-order
NLO responses are hardly expected from ordinary LHPs due to their
intrinsic centrosymmetric structures, but are highly desirable for
advancing their applications in the next generation integrated photonic
circuits. Here we demonstrate the fabrication of a novel noncentrosymmetric
LHP material by introducing chiral amines as the organic component.
The nanowires grown from this new LHP material crystallize in a noncentrosymmetric P1 space group and demonstrate highly efficient second harmonic
generation (SHG) with high polarization ratios and chiroptical NLO
effects. Such a chiral perovskite skeleton could provide a new platform
for future engineering of optoelectronic functionalities of hybrid
perovskite materials.