Growth and characterization of neodymium and ytterbium doped barium chloride dihydrate single crystals

• Pure, Nd doped, Nd:Yb co-doped barium chloride dihydrate single crystals were grown.
• Spectral overlap of absorption bands of Nd3+ and Yb3+ around 1000 nm was observed.
• BaCl2·2H2O:Nd:Yb crystal show a significant photoluminescence spectral enhancement.
• Pure centrosymmetric BaCl2·2H2O crystal gave an unusual upconverted green emission.
• Energy transfer in BaCl2·2H2O:Nd:Yb crystal leads to high upconverted green emission.

Pure, Nd doped and Nd:Yb co-doped barium chloride dihydrate (BaCl2·2H2O) single crystals were grown and analyzed with various characterization techniques. The measured unit cell parameters show that the grown crystals belong to monoclinic system. Powder X-ray diffraction spectra indicates that the dopants enhance (2 1 0) orientation of BaCl2·2H2O crystal. X-ray rocking curves have been recorded to analyze the crystallinity of the grown single crystals. Optical absorption spectra of the grown crystals contain strong absorption bands in infrared region. Spectral overlap of absorption bands of Yb3+ and Nd3+ ion around 850 nm–1060 nm in Nd:Yb co-doped single crystal indicates the prospect of energy transfer between them. A significant enhancement has been observed in the photoluminescence spectrum of Nd:Yb co-doped single crystal recorded with 244 nm laser excitation. Photon upconversion ability of the crystals was tested using Nd:YAG laser of wavelength 1064 nm. An unusual upconverted green emission from pure centrosymmetric BaCl2·2H2O single crystal has been observed. The energy of upconverted green light of Nd:Yb co-doped barium chloride dihydrate single crystal is higher which may be due to energy transfer occurred between Yb3+ and Nd3+ ions. FTIR and FT-Raman spectral analyses were carried out to study the vibrational modes of pure, Nd doped and Nd:Yb co-doped BaCl2·2H2O single crystals.