Mechanical, thermal and laser damage threshold analyses of II group metal complexes of thiourea

Single crystals of thiourea metal complexes with selected Group II metal ions, Zinc and Cadmium, have been grown by solvent evaporation technique. The crystals grown are bisthiourea zinc chloride (BTZC) and bisthiourea cadmium chloride (BTCC). Following an improved photopyroelectric technique, the thermal transport properties have been determined. It is found that BTCC has a higher heat capacity (304.09 J kg−1 K−1) than BTZC (255.24 J kg−1 K−1), and hence BTCC has better thermal stability. Vicker's microhardness measurements reveal that these materials have reverse indentation size effect and belong to the category of soft materials. Elastic stiffness is found to be higher for BTCC (1.57 GPa) than BTZC (0.76 GPa). The roles of the Group II metal ions in improving the mechanical and thermal stability of the metal complexes are discussed. Multi-shot laser damage studies on these materials reveal that BTCC has a higher laser damage threshold (15 GW cm−2) than BTZC (6 GW cm−2).

Research highlights
► The role of the Group II metal ions in improving the stability is discussed.
► BTCC has a higher heat capacity than BTZC.
► Elastic stiffness is found to be higher for BTCC than BTZC.
► Microscopy studies confirm the damage is due to thermo-chemical ablation.
► BTCC has a higher laser damage threshold than BTZC.