Design and DFT calculations of optoelectronic material based on thiazolobenzimidazole-coupled isatin derivatives.

Isatin derivatives were condensedby refluxing ethanol with thiazolobenzimidazole, yielding four linked 2-oxoindolin-3-ylidene)benzo [4,5]imidazo-[2,1-b]thiazol-3(2H)-ones. Thermal evaporation was used to deposit thin films of the produced 2-oxoindolin-3-ylidene)benzo [4,5]imidazo-[2,1-b]thiazol-3(2H)-one derivatives, which underwent thorough analysis employing UV–Vis and NIR spectroscopy. The spectral profiles of these materials were scrutinized with respect to their absorption, dielectricconstants, and dispersion propertiesand compared to previously published data. The current samples were suitable for application in optoelectronic devices, particularly as solar-absorbent materials, due to their high absorption coefficient (α > 105cm−1) at a solar maximum wavelength (λ = 500 nm). Additionally, their band and optical gap energies have been determined as 3.60, 3.56, 2.53, and 3.24 eV. The conclusions drawn from geometry optimization and nonlinear optical (NLO) calculations, performed using density functional theory (DFT) with the Becke, 3-parameter, Lee–Yang–Parr (B3LYP) approach at the 6–311G (d,p) level, further support these findings. • 2-oxoindolin-3-ylidene)benzo[4,5]imidazo-[2,1-b]thiazol-3(2H)-ones had been Synthesized. • Thin films deposited via thermal evaporation showed a bandgap energy of 3.60 to 2.53 eV, ideal for optoelectronic applications. • High absorption coefficients (α > 105 cm-1), especially at λ = 500 nm, suggesting solar absorber material potential. • DFT calculations confirmed superior NLO characteristics compared to urea, supporting experimental findings. • Synthesized compounds show promise for optoelectronic applications, highlighting their impact on materials science. [ABSTRACT FROM AUTHOR]