Low temperature photoluminescence studies on semiorganic tris thiourea copper (I) chloride single crystal

Semiorganic tris thiourea copper (I) chloride (TTCC) single crystals have been synthesized from copper (II) chloride via slow evaporation technique. The stoichiometry of the grown anhydrous complex crystal has been confirmed by elemental CHNS (C, H, N and S) and atomic absorption spectrophotometric (AAS) analysis. The crystal structure with space group has been confirmed by single crystal and powder X-ray diffraction (XRD) studies. The FTIR study assigned the presence of functional groups and confirmed the co-ordination of metal ions with thiourea. It also confirmed the transition from Cu2+ to Cu+ when thiourea combined with Copper (II) chloride. The optical transparency of the crystal has been studied by UV-Vis spectrum and deduced the energy gap. The room temperature Photoluminescence (PL) spectrum reported maximum emission line at 410.92 nm and Stokes shift has been determined as 75 nm or 16.5 eV. Low temperature luminescence study from 300 K to 77 K exhibited three blue emission peaks and one green emission peak. The green emission band has been assigned to recombination of an electron in a shallow trap and Cu2+. Blue emission has been attributed to S2- vacancies. The interesting hysteresis loop has been exhibited by the variation of energy gap with low temperature. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)