Synthesis, structural, spectral, optical characterizations of (3-cyano-9-methyl-5-oxo-1, 5-dihydro-2H-chromeno [4,3-b] pyridin-2-ylidene) propanedinitrile (CMOCPP) and its photodiode application

• Reaction of 6-methylchromone-3-carbonitrile with malononitrile dimer gives CMOCPP.
• XRD and TEM support nanostructure characteristics with nanoflower-like structure.
• Two direct allowed transitions were observed with band gaps of 1.49 and 3.83 eV.
• CMOCPP/p-Si heterojunction may open a new perspective in a field of photosensors.

Reaction of 6-methylchromone-3-carbonitrile (1) with malononitrile dimer gave the unexpected (3-cyano-9-methyl-5-oxo-1,5-dihydro-2H-chromeno[4,3-b]pyridin-2-ylidene) propanedinitrile. Structure was deduced based on its correct elemental analysis and various spectral data. Moreover, samples were prepared and characterized using X-ray diffraction and transmission electron microscope. The X-ray diffraction data was analyzed on the basis of Scherrer and Williamson–Hall and compared with particle size analysis results. The results indicate that the complex is well crystalline and correspond to triclinic crystal structure. The photoluminescence spectrum shows one strong visible emission which may be attributed to the radiative recombination of the self-trapped excitons. The absorption characteristic shows two characterized peaks at 352 and 751 nm. The absorption spectrum, in the visible region, is found to be similar to the photoluminescence spectrum and both shapes are mirror images. Analysis of the absorption coefficient near the absorption edge reveals that the optical band gaps are direct allowed transition with values of 1.49 and 3.85 eV. The prepared heterojunctions are found to behave good rectifying property. The response to visible light illumination results suggests that the prepared compound based heterojunction may open a new perspective in optoelectronic applications.

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