Laser-engineered PANI-derived Carbon TiO2 electrode for integrated photocharging µ-supercapacitor

Development of photo-induced self-charging devices that can integrate solar energy harvesting and storage in a single unit is premised on stability of the electrode components. Therefore, we report some carbonized titanium oxide composite (CTPs) electrode materials synthesized via pyrolysis of polyaniline titanium isopropoxide precursors. Microstructure and chemical state investigations revealed synergistic structural interaction of nitrogen-doped graphitic carbon matrix with semicrystalline TiO2 film’s particles. Optical characterization showed that some of the CTP samples exhibit strong UV absorption and defect-induced photoactivity with wide optical bandgap energy of about 3.55 eV. Cyclic voltammetry and galvanostatic charge-discharge (GCD) experiments presented values of areal capacitance that improved from 3.81 mF cm-2 (dark) to 5.92 mF cm-2 under 12.5 mW cm-2 UV illumination, high energy density (0.72 μWh cm-2), and long discharge duration. Reduction in series resistance and steeper Warburg slope under illumination were also achieved. Higher donor density and a negative shift in flat-band potential with increasing UV intensity were obtained from Mott–Schottky analysis. The results of the study suggested the viability of CTP electrode for light-tuning and recharge mechanism enabling self-powered microelectronics devices.