Novel UV Sensing and Photocatalytic Properties of DyCoO₃

Abstract

Oxides with the perovskite type structure of formula LnCoO 3 , where Ln is a rare earth element, have unique physical and chemical properties. These materials are applied in catalysis, gas sensors, and electrodes for solid oxide fuel cells, among others. In this work, single-phase DyCoO 3 was obtained at 900 ∘ C using the solution-polymerization method. The microstructure of this material corresponds to a dendritic-type shape, with grain size between 0.2 and 8 m and abundant porosity. The ultraviolet (UV) sensing characterization was performed on sintered pellets made with the as-prepared DyCoO 3 powder. The UV source was a light emitting diode (LED) of wavelength ( ) of 365 nm. The detection of this radiation, with constant optical irradiance (E e ), produced uniform and reproducible response patterns. When E e was increased, the graphs revealed a quantitative detection of the light. Analogous results were obtained using light of larger wavelengths: = 400, 449, and 642 nm. The graphs display a decrease on the variation of the photocurrent by increasing , corresponding to a decrease on the energy of the incoming photons. On the other hand, the photocatalytic decomposition of malachite green under UV radiation was investigated using powder of DyCoO 3 . The results show a decrease of the absorbance by increasing the UV exposure time, indicating the degradation of the dye. Since DyCoO 3 is a p-type semiconductor material, the generation of electrical charge carriers under UV radiation explains its photocurrent and photocatalytic properties. In general, these properties can be applied in UV sensors to prevent skin cancer, photoconductive materials for solar photocells, and photocatalysis to decompose organic dyes.

Determining the Photoelectrical Behavior and Photocatalytic Activity of an h-YMnO3 New Type of Obelisk-like Perovskite in the Degradation of Malachite Green Dye

“…When exposed to this wavelength, the photocurrent increased to 4.55 × 10 −8 A, while in the dark, the photocurrent decreased until it reached 8.50 × 10 −10 A. A similar photoelectric response has been found in a P-type oxide semiconductor featuring a perovskite structure [28,29]. It has to be pointed out that the applied voltage also contributes to the photoelectric material response.…”