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)

• Condensation reaction of 6-bromochromone-3-carboxaldehyde (1) with dimedone afforded BOCTTX.
• BOCTTX is thermally stable up to 583 K.
• Two direct allowed transitions were observed with band gaps of 2.2 and 3.3 eV.
• Sensitivity of BOCTTX/p-Si diode increases with increasing illumination intensity.
• Results of BOCTTX/p-Si diode suggest possibility for optoelectronic application.

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, 1H NMR, 13C 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/cm2. 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.

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