![]() ![]() In the present work a ZnO/CsPbBr3 nanocomposite based on nanocrystalline ZnO and colloidal cubic-shaped perovskite CsPbBr3 nanocrystals (NCs) capped by oleic acide and oleylamine was synthesized. The development of sensor materials of which gas sensitivity activates under light illumination is of great importance for the design of portable gas analyzers with low power consumption. By this sensitization approach, the absorption spectrum of the sensor layer can be matched to the emission spectrum of the light source, which allows to optimize the efficiency of excitation energy transfer from the light source to the sensor layer and shift the absorption edge to lower radiation energy. To enhance the sensitivity of sensor materials to visible light, wide-gap metal oxides can be combined with substances that strongly absorb visible light (sensitizers), such as dyes, plasmon and non-plasmonic metal nanoparticles, narrow-band semiconductor nanoparticles, carbon nanomaterials and semiconductor quantum dots. The gas sensitivity of nanocrystalline wide-gap metal oxide layers is also activated by visible-light irradiation, but the effect is not pronounced, since it is affected by light absorption due to impurities or defects in the crystal structure of semiconductor particles. Next, approaches to the description of the mechanism of the sensor response of semiconductor sensors under the action of light are considered. In the case of visible light activation, the approaches used to enhance the photo- and gas sensitivity of wide-gap metal oxides are (i) doping (ii) spectral sensitization using dyes, narrow-gap semiconductor particles, and quantum dots and (iii) addition of plasmon nanoparticles. When activated by UV light, the typical approaches for creating materials are (i) the use of individual metal oxides, (ii) chemical modification with nanoparticles of noble metals and their oxides, (iii) and the creation of nanocomposite materials based on metal oxides. The activation of the gas sensitivity of semiconductor materials by both UV and visible light is considered. Information on the photoelectric and optical properties of nanocrystalline oxides SnO2, ZnO, In2O3, and WO3, which are the most widely used sensitive materials for semiconductor gas sensors, is presented. The review deals with issues related to the principle of operation of resistive semiconductor gas sensors and the use of light activation instead of thermal heating when detecting gases.
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