New photosensing properties of nanostructured GdCoO3 in the ultraviolet (A)-visible-near infrared range

In this work, single-phase GdCoO3 was obtained by the solution-polymerization method, at 750 °C. Observation of its morphology by electron microscopy revealed the formation of a network of nanoparticles and abundant porosity. The bandgap energy of this material was determined by the Tauc method, giving approximately 0.54 eV, which suggested its possible application as a photosensor material. The photoconductive properties were investigated on sintered pellets made with the as-prepared powder. For their characterization, light emitting diodes (LEDs) that produce radiation from the ultraviolet-A (UV-A) to near-infrared (NIR) were used. The results revealed a reliable and reproducible photoconductive response over multiple on/off light pulses. Good sensitivity to the wavelength and optical irradiance of light was observed, confirming its possible use as a wide-spectrum photosensor. The mechanism of photoconductivity is explained by the formation of electron-hole pairs in the oxide, due to the transfer of energy from photons.