Synthesis and photosensitivity characterizations of 9-(6-bromo-4-oxo-4H-chromen-3-yl)-3,4,6,7-tetrahydro-3,3,6,6-tetramethyl-2H-xanthene-1,8-(5H,9H)-dione(BOCTTX)

Abstract

Condensation reaction of 6-bromochromone-3-carboxaldehyde (1) with dimedone afforded 9-(6-bromo-4-oxo-4H-chromen-3-yl)-3,4,6,7-tetrahydro-3,3,6,6-tetramethyl-2H-xanthene-1,8-(5H,9H)-dione (3, BOCTTX). Structure of BOCTTX was deduced based on its correct elemental analysis and spectral data (IR, H NMR, C NMR and mass spectra). Thin films of BOCTTX were prepared in this study by using spin coating technique. X-ray diffraction, scanning electron microscope analysis were studied for study the crystal and morphology characterization of BOCTTX. The results indicate that BOCTTX has a polycrystalline nature with monoclinic structure. From differential scanning calorimetry, BOCTTX is found to be thermally stable up to 583 K and the chemical structure plays an important role in the thermal decomposition process. The optical absorption of the film was studied in the UV-Vis spectral range and the value of two allowed energy gaps of 2.2 and 3.3 eV. Current-voltage characteristics of BOCTTX based devices were studied in dark and under various illumination intensities in the range 20-100 mW/cm . Electrical and photoelectrical parameters were studied as a function of light intensity. The obtained results exhibits photoconductivity cauterization and suggest that the diode can be used as a photodiode in optoelectronic sensor application.