An excellent lead oxyiodide with a strong second-harmonic generation response and a large birefringence induced by the oriented arrangement of highly distorted [PbO4I2] polyhedra. Issue 17 (18th July 2022)

• Record Type: Journal Article
• Authors: Zhou, Zi-Qi; Fu, Rui-Biao; Tang, Hong-Xin; Ma, Zu-Ju; Wu, Xin-Tao
• Is Part Of: Inorganic chemistry frontiers. Volume 9:Issue 17(2022)
• Page Start: 4464
• Page End: 4469
• Publication Date: 2022-07-18
• Subjects: Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2qi01143c
• Languages: English
• ISSNs: 2052-1553

Abstract

Abstract : K2 I[PbI(OOCCH2 COO)] featuring the strongest second-harmonic generation response among malonates, a large birefringence, a wide transparent window and good stability is induced by the oriented arrangement of highly distorted bifunctional [PbO4 I2 ] polyhedra. Abstract : Nonlinear optical (NLO) crystals are an important component in modern lasers. Nevertheless, it is a great challenge to rationally synthesize NLO crystals with strong second-harmonic generation (SHG) responses and large birefringence. Herein, a cationic substitution strategy has been successfully developed to transform SHG-inert centrosymmetric Cs2 I2 [Pb(OOCCH2 COO)] into SHG-active K2 I[PbI(OOCCH2 COO)] with a NCS polar structure. K2 I[PbI(OOCCH2 COO)] features highly distorted [PbO4 I2 ] polyhedra that are aligned in an oriented arrangement, resulting in the effective superposition of their microscopic second-order nonlinear susceptibilities. Remarkably, K2 I[PbI(OOCCH2 COO)] not only exhibits the strongest phase-matching SHG response of 6.3 × KDP to date among malonates, but also possesses a large birefringence (Δ n obv. = 0.218@546 nm) and good thermal stability. As elucidated through theoretical calculations its strong SHG response and large birefringence mainly originate from the highly distorted [PbO4 I2 ] polyhedron. This paper presents a new approach for the development of NLO crystals with prominent performance.