The modification in the photo-physical properties via transformation of synthetic dihydrated Znq2 to anhydrous (Znq2)4 tetramer by sublimation process

A prominent green emitting anhydrous (Znq2)4 tetramer phosphor has been produced by the sublimation in Ar-atmosphere from dihydrated Znq2. The dihydrated Znq2 was synthesized by the co-precipitation method under normal atmospheric condition. Structural changes which are responsible for change in their photo-physical properties have been confirmed by the XRD, FTIR, NMR analysis and relative stability by the TGA/DTA analysis. The dependence of UV-visible absorption spectrum, in different acidic and basic mediums at different concentrations on the alteration of phase from dihydrated Znq2 to anhydrous (Znq2)4 tetramer leading to the change in the band gap, has been noted. A photoluminescence spectrum of solid and of solution state and structural dependence on emission and excitation wavelength, revealing the modification in the structure, is responsible for a prominent green emission. Solvato-chromatic effect on PL emission leading to blue shift by the addition of acidic solvents and a red shift by basic solvents has also been reported. The structural formation and experimental band gap energy information has been supported by the quantum chemical calculations using DFT Computational study. We conclude from the study that the produced anhydrous (Znq2)4 tetramer phosphor has a potential application as a prominent green dopant in OLEDs including indoor lighting. Additionally, this study gives an insight into the spectroscopy of Zinc (II) quinolate complex.