Equivalent cation-tuning to realize a new Ce(iv) fluoride with excellent comprehensive nonlinear optical performances

Abstract

Exploring nonlinear optical (NLO) halide materials has become a hot research field owing to their diverse structures and excellent optical properties. In this paper, a new inorganic tetravalent cerium fluoride NH₄Ce₃F₁₃ was obtained. It crystallizes in the polar space group of Pmc2₁ and exhibits a three-dimensional {[Ce₃F₁₃]⁻}_∞ framework, which is composed of {[CeF₈]⁴⁻}_∞ chains and {[CeF₆]²⁻}_∞ layers formed by CeF₉ polyhedra, with the NH₄⁺ cation balancing the charge. NH₄Ce₃F₁₃ exhibits a strong second-harmonic generation (SHG) response among inorganic metal fluorides of about 1.2 times greater than that of KH₂PO₄ (KDP) and a high laser-induced damage threshold (LIDT), which is 39 times more than that of AgGaS₂. Besides, NH₄Ce₃F₁₃ possesses the largest band gap among Ce(IV)-containing NLO materials. This work provides a good case for exploring high-performance NLO fluoride materials.