Noncentrosymmetric (NCS) solid solutions: elucidating the structure-nonlinear optical (NLO) property relationship and beyond

A systematic approach toward the discovering of novel functional noncentrosymmetric (NCS) materials revealing technologically useful applications is an ongoing challenge. This Frontiers article investigates a series of NCS solid solutions with respect to their crystal structure and second-harmonic generation (SHG) response. The solid solutions include NCS polar aluminoborates, Al 5− x Ga x BO 9 (0.0 ≤ x ≤ 0.5), rare earth element-doped bismuth tellurites, Bi 2− x RE x TeO 5 (RE = Y, Ce, and Eu; 0.0 ≤ x ≤ 0.2), layered perovskites, Bi 4− x La x Ti 3 O 12 (0.0 ≤ x ≤ 0.75: Aurivillius phases) and CsBi 1− x Eu x Nb 2 O 7 (0.0 ≤ x ≤ 0.2: Dion-Jacobson phases), calcium bismuth oxides, Ca 4 Bi 6− x Ln x O 13 (Ln = La and Eu; x = 0, 0.06 and 0.12), and sodium lanthanide iodates, NaLa 1− x Ln x (IO 3 ) 4 (Ln = Sm and Eu; 0 ≤ x ≤ 1). The origin of SHG for all the NCS solid solutions is discussed and the detailed structure-nonlinear optical (NLO) property relationships are elucidated. In addition, photoluminescence (PL) properties and subsequent energy transfer mechanisms for NCS solid solutions are provided. A series of noncentrosymmetric (NCS) solid solutions and their structure-nonlinear optical property relationship are introduced for designing novel NCS materials more systematically.