Growth, electronic structure and properties of Rb2Ti1.95Yb0.05(PO4)3 crystals

Rb 2 Ti 1.95 Yb 0.05 (PO 4 ) 3 crystals with langbeinite-type structure were grown by high-temperature solution method. The chemical composition and electronic structure were analyzed using inductive coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The deconvolution of Ti 2p 3/2 photoemission line reveals two peaks at 459.3 eV and 458.1 eV, indicating titanium existence in two valence states: Ti 4+ (459.3 eV) and Ti 3+ (458.1 eV). The reduced BE difference ΔBE (O 1s-Ti 2p 3/2 ) shows stronger ionicity of Ti–O bonds in Rb 2 Ti 1.95 Yb 0.05 (PO 4 ) 3 compared with RbTiOPO 4 . Additionally, UV absorption, specific heat, and second harmonic generation (SHG) efficiency were studied. The UV absorption edge of the Rb 2 Ti 1.95 Yb 0.05 (PO 4 ) 3 crystal was observed at 368 nm. The SHG intensity of Rb 2 Ti 1.95 Yb 0.05 (PO 4 ) 3 is 5–6 times greater than that of KDP crystal when the particle size is between 38 and 74 μm.