KPb3(o-C5H4NCOO)2Cl5: a brand-new stable lead chloride with good comprehensive nonlinear optical performance

Abstract

The discovery of nonlinear optical (NLO) crystals with excellent performance is still a great challenge. Herein, a brand-new stable lead chloride, KPb₃(o-C₅H₄NCOO)₂Cl₅, has been successfully synthesized and well characterized. Interestingly, the π-conjugated nicotinate group is simultaneously connected by a [PbO₂Cl] trigonal pyramid and a distorted [PbNCl₃] polyhedron into an ordered arrangement. KPb₃(o-C₅H₄NCOO)₂Cl₅ exhibits good comprehensive NLO performance, including a high laser damage threshold (LDT) of 147 MW cm⁻², an enhanced phase-matching SHG response of 2 × KDP (KH₂PO₄), a suitable birefringence (0.13@1064 nm), a wide transparent window of 0.38–6.10 μm and facile crystal growth. Its SHG response originates from the oriented arrangement of hybrid layers. Remarkably, KPb₃(o-C₅H₄NCOO)₂Cl₅ displays thermally stable behavior up to 300 °C under an air atmosphere. This research puts forward a feasible idea for the exploration of new NLO crystals.