A Series of Rare-Earth Borates K₇MRE₂B₁₅O₃₀ (M = Zn, Cd, Pb; RE = Sc, Y, Gd, Lu) with Large Second Harmonic Generation Responses

Abstract

A series of new rare-earth borate crystals K7MRE2B15O30 (M = Zn, Cd, Pb; RE = Sc, Y, Gd, Lu) were synthesized by solid-state reaction method. All of the title compounds crystallize in the noncentrosymmetric trigonal space group R32, and their structures consist of the B5O10 groups and the KO8, KO6, MO6, and REO6 polyhedra. Each isolated B5O10 group is connected by the REO6 (Sc3+, Y3+, Gd3+, Lu3+) groups forming an intricate three-dimensional network, and the K+ and M2+ (Zn2+, Cd2+, Pb2+) cations fill into the void space. Because of the introduction of different nonlinear optical (NLO)-active structural units (cations with d10 electronic configuration and stereoactive lone pairs) into rare-earth metal borates, these compounds exhibit second harmonic generation (SHG) responses ranging from 1.5 to 2.1 times that of KH2PO4 (KDP), and are phase-matchable. Interestingly, this work indicates that the NLO properties can be artificially adjusted by systematically replacing the bivalent M2+ and trivalent RE3+ cations with NLO-active structural units, which provides a new way to design new NLO materials. Thermal analyses, IR spectra, and UV–Vis–NIR diffuse reflectance spectra were also reported in this work. In addition, the first-principles calculation was employed for better understanding of the structure–properties relationships of these compounds. Especially, the origins of SHG responses were well demonstrated by the SHG-density technique.

A new disordered langbeinite-type compound, K2Tb1.5Ta0.5P3O12, and Eu3+-doped multicolour light-emitting properties

“…The K1 and K2 atoms are View of the crystal structure of K 2 Tb 1.5 Ta 0.5 (PO 4 ) 3 along the a axis. 2.933 (10)-3.295 (12) Å , which fall within the range of values common for inorganic potassium oxide compounds (Xie et al, 2018;Kremenović & Vulić, 2014).…”

Synthesis, characterization, and theoretical analysis of three new nonlinear optical materials K7MRE2B15O30 (M= Ca and Ba, RE= La and Bi)

“…S4. According to the previous literatures [47,48,[68][69][70], the characteristic peaks of Compound I can be described as follows: the peaks at 1,338, 1,262, and 1,194 cm −1 are mainly due to the asymmetric stretching of the BO 3 units, and the peak at 1,020 cm −1 is attributed to the BO 4 asymmetric stretching vibration. The peak at 931 cm −1 can be assigned to the symmetric stretching of BO 3 .…”

“…[45,46]. In addition, some previous work [29,[47][48][49][50][51][52] (III) were synthesized. Here, the syntheses, structures, thermal behavior, IR spectrum, UV-Vis-NIR spectrum, and NLO properties of the title compounds are presented.…”

Research and Development of Zincoborates: Crystal Growth, Structural Chemistry and Physicochemical Properties

“…Insofar as we know, there are a number of zinc-containing borates reported in the UV/DUV regions. For instance, Ba 3 (ZnB 5 O 10 )PO 4 (~180 nm) [60], Cs 3 Zn 6 B 9 O 21 (~200 nm) [45,46], AZn 2 BO 3 X 2 (A = Na, K, Rb, NH 4 ; X = Cl, Br) series (~190-209nm) [58,59], K 7 ZnSc 2 B 15 O 30 (~200 nm) [128], K 3 ZnB 5 O 10 (~190 nm) [129], Cs 12 Zn 4 (B 5 O 10 ) 4 (below 185 nm) [130], etc. Hence, the Zn-containing borate system is also a candidate for exploring promising UV even DUV materials.…”