PO(CH2CH2CF3)3: an organic ultraviolet nonlinear optical material without any anionic group

Abstract

Researchers have focused on inorganic compounds to design deep ultraviolet (UV) nonlinear optical (NLO) materials according to anionic group theory, such as CO₃²⁻, NO₃⁻, SO₄²⁻ and PO₄³⁻ anions. Here we provide a new route to design an UV NLO material using a pure organic compound without any anions. Compound PO(CH₂CH₂CF₃)₃ 1, an UV NLO material, has light transmittance up to 83% in the UV spectral region which is larger than most inorganic UV NLO materials. It also displays a wide transparent band, a SHG response of 0.30 × KH₂PO₄, and a cut-off edge below 200 nm. It displays ladder-like nonlinear optical properties weakened by 1.4 times at around T_c, making compound 1 a potential temperature-controlled UV NLO material. Theoretical analyses reveal that the nonlinear optical properties are primarily due to O-2p, P-2p and F-2p.