AZn(PO₃)₃ (A = K, Rb): Deep-Ultraviolet Nonlinear Optical Phosphates Derived from Synergy of a Unique [ZnO₆] Octahedron and a [PO₃]_∞ Chain

Abstract

Deep-ultraviolet (deep-UV) nonlinear optical (NLO) phosphates have become a continuing hot spot since the discovery of Ba3P3O10X. Herein, we report two new deep-UV NLO phosphates, KZn­(PO3)3 and RbZn­(PO3)3, crystallizing in the asymmetric R3 (No. 146) space group with a three-dimensional (3D) network constructed by [PO3]∞ chains and distorted C 3v [ZnO6] octahedra. Both compounds exhibit phase-matchable behaviors with relatively strong powder SHG intensities (about 0.6× and 0.7× those of the benchmark KDP) and short deep-UV cutoff edges (<200 nm). First-principles calculations reveal the synergy of the distorted [ZnO6] octahedron and the flexible [PO3]∞ chain that contribute respectively to the d 16 value by 14 and 84% in KZn­(PO3)3 or 6 and 93% in RbZn­(PO3)3. Remarkably, the SHG-active [ZnO6] herein is pointed out for the first time, which offers an unconventional access to the design and searches for deep-UV NLO material candidates.

A deep ultraviolet transparent birefringent monofluorophosphate: Cd2.5(NH4)2(PO3F)3Cl ⋅ 2H2O

“…The absorption cutoff edge is consistent with those of the d 10 -TM phosphates, such as CsLiCdP 2 O 7 (< 190 nm), [25] RbCdP 3 O 9 (< 190 nm), [26] Rb 2 Zn 3 (P 2 O 7 ) 2 (< 190 nm) [27] and RbZn(PO 3 ) 3 (< 200 nm). [24] This observation agrees with that the d 10 cations with fully occupied electron can produce a larger atomic energy level difference which eliminates the redshift. [24] The infrared (IR) spectrum is shown in Figure 4d.…”

“…[24] This observation agrees with that the d 10 cations with fully occupied electron can produce a larger atomic energy level difference which eliminates the redshift. [24] The infrared (IR) spectrum is shown in Figure 4d. The bands around 3330, 3039-3204 and 1689 cm À 1 are assigned to the asymmetric, symmetric stretching and bending vibrations of the H 2 O molecule, respectively.…”

“…[23] Differently, the d 10 cations with a fully occupied d electron configuration can produce a larger atomic energy level difference. [24] Thus, a d 10 -cation containing compound will eliminate the unwanted redshift of the absorption cutoff edge, achieving a transparency in deeper spectral regions; such as CsLiCdP 2 O 7 (λ cutoff < 200 nm), [25] RbCdP 3 O 9 (λ cutoff < 190 nm), [26] A 2 Zn 3 (P 2 O 7 ) 2 (A=Rb, Cs) (λ cutoff < 190 nm) [27] and AZn(PO 3 ) 3 (A=K, Rb) (λ cutoff < 200 nm). [24] Herein, we report a new Cd 2.5 (NH 4 ) 2 (PO 3 F) 3 Cl • 2H 2 O (CNPFC), featuring a [Cd 3 P 2 O 12 ClF 2 ] ∞ double-layer that is stacked along the a axis.…”

“…[24] Thus, a d 10 -cation containing compound will eliminate the unwanted redshift of the absorption cutoff edge, achieving a transparency in deeper spectral regions; such as CsLiCdP 2 O 7 (λ cutoff < 200 nm), [25] RbCdP 3 O 9 (λ cutoff < 190 nm), [26] A 2 Zn 3 (P 2 O 7 ) 2 (A=Rb, Cs) (λ cutoff < 190 nm) [27] and AZn(PO 3 ) 3 (A=K, Rb) (λ cutoff < 200 nm). [24] Herein, we report a new Cd 2.5 (NH 4 ) 2 (PO 3 F) 3 Cl • 2H 2 O (CNPFC), featuring a [Cd 3 P 2 O 12 ClF 2 ] ∞ double-layer that is stacked along the a axis. We also demonstrate an interesting structure relationship among three related compounds, CdPO 3 F • 2H 2 O, Cd 5 (PO 4 ) 3 Cl and CNPFC, which is driven by the diverse coordination geometries and inter-unit connections of the Cdcentered polyhedra as well as the as well as different hydrogen bonding interactions.…”

“…If the d ‐ d and f ‐ f transitions exist, the band gap ( E g ) of such TM‐containing compound will be thus small, for instance, KTP ( λ cutoff =350 nm), [20] Pb 3 Zn 3 WP 2 O 14 ( λ cutoff =317 nm), [21] KCsMoP 2 O 9 ( λ cutoff =260 nm), [22] α ‐KCsWP 2 O 9 ( λ cutoff =329 nm) and β ‐KCsWP 2 O 9 ( λ cutoff =270 nm) [23] . Differently, the d 10 cations with a fully occupied d electron configuration can produce a larger atomic energy level difference [24] . Thus, a d 10 ‐cation containing compound will eliminate the unwanted redshift of the absorption cutoff edge, achieving a transparency in deeper spectral regions; such as CsLiCdP 2 O 7 ( λ cutoff <200 nm), [25] RbCdP 3 O 9 ( λ cutoff <190 nm), [26] A 2 Zn 3 (P 2 O 7 ) 2 (A=Rb, Cs) ( λ cutoff <190 nm) [27] and AZn(PO 3 ) 3 (A=K, Rb) ( λ cutoff <200 nm) [24] …”