Facile auto combustion synthesis of CuO nanoparticles and their structure-opto-dielectric and photodetection performances: An effect of different citric acid concentrations

Copper oxide (CuO) belongs to the p-type semiconductors family and have several applications in various fields like solar cell, supercapacitor, dielectrics, data storage, biomedical, optoelectronics, etc. Hence, in the current work, we have prepared the nanoparticles (NPs) of CuO by flash combustion route using different concentrations of citric acid (CA). XRD analysis confirms the phase of the synthesized CuO NPs. A vibrational study also approves the synthesis of NPs of CuO. A systematic reduction in peak intensities and increase of FWHM was noticed in XRD and FT-Raman patterns, which indicates the size reduction with increasing the CA concentrations in CuO. The particle size determined by the W-H plot was observed to be reduced from 25 to 19 nm. SEM analysis confirms the morphology and approximate size of the prepared NPs. The CA concentrations enhanced the energy gap from 2.5 eV to 2.9 eV. The dielectric study shows the enhancement in dielectric constant with CA concentrations/size reduction, and its value lies between 95 and 110. The AC electrical conductivity also improved with CA concentration and frequency. The increasing concentrations of CA fuel led to a decreased photocurrent, and the gamma values for 1 g and 3 g CA added CuO NPs based photodetector were obtained similar to 0. 77 and 0.95. This means that at higher CA concentrations, the size is reduced, resulting in the reduction of traps in the device. Also, the photosensitivity of CuO has been improved with light intensity; however, it was found to be lower for 3 g CA-added CuO compared to 1 g CA-added CuO NPs-based photodetectors. Results indicate that the prepared NPs are of tremendous application in optoelectronic devices.