Methylpiperazine based 0D chiral hybrid lead halides for second harmonic generation.

Hybrid organic-inorganic metal halides (HOMHs) have recently attracted broad research interest for their structural tunability and remarkable optoelectronic properties. Among them, chiral HOMHs have demonstrated promising applications in second-order nonlinear optics (NLO) on account of their inherent noncentrosymmetric structures. Herein, we synthesized two new chiral HOMHs, ( S -/ R -2-C 5 H 14 N 2 ) 2 PbI 6 , based on S -/ R -2-methylpiperazine chiral amines. They feature a band gap close to 2.9 eV with high phase purity as well as environmental and thermal stability. The induction of the chiral optical properties of ( S -/ R -2-C 5 H 14 N 2 ) 2 PbI 6 by chiral organic cations was verified by circular dichroism (CD) spectroscopy. Moreover, the resulted HOMHs materials demonstrate a strong second harmonic generation response with a large laser damage threshold (∼2.97 mJ cm -2 ), showing promising applications in NLO photonic devices.