Thermal and optoelectrical properties of cobalt doped and undoped strontium L(+) tartrate pentahydrate single crystals

Single crystals of intrinsic strontium L(+) tartrate pentahydrate (IST) and cobalt-doped strontium L(+) tartrate pentahydarte (CoDST) are grown by gel diffusion technique with the growth parameters optimized to lab temperature of 23.5 degrees C. Stoichiometric composition and the cationic distribution of the crystals are determined from EDAX technique. FTIR and Raman spectral analyses reveal the presence of water molecules, O-H, C-H, C-O, C = O and C-C bonds in the crystals. Thermogravimetric analysis confirms that the crystals attain thermal stability in oxide state through four stages of decomposition, undergoing weight loss in each stage. This study also reveals the pentahydrate nature of both the crystals. While IST crystal material possesses a chemical formula: SrC4H4O6.5H2O with a molecular weight of 325.77, the CoDST crystal is seen to possess a chemical formula: Sr0.9836Co0.0164C4H4O6.5H2O with a molecular weight of 325.29 and a cationic distribution ratio of Sr2+:Co2+ = 59.98:1. UV-Visible spectral studies, in the range of 190-1100 nm, show that both the crystals are transparent to visible region. Optical transmittance of 97.8% of the IST lattice is observed to have increased to 98.91% on account of doping. Consequently, the optical band gap energy of 5.623 eV of IST lattice is decreased to 5.55 eV on account of doping. Due to doping of Co2+ ions, CoDST crystal is observed to possess a relatively lower leakage resistance and a higher conductivity as compared to those of IST crystal, for the range of applied voltage of 0-200 V. (c) 2021 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the Global Conference on Recent Advances in Sustainable Materials 2021.