Journal of Solar Energy Research Updates

Glucose Sensing Optionally in Optical and Optoelectrical Modes Based on Au-TiO2 Schottky Nanojunctions

Lu Ma — 2024-02-27

Abstract: In recent years, metallic nanostructures have been extensively researched in the field of plasmonic for optical and optoelectronic applications such as biochemical sensing. However, an additional optoelectronic converter or spectrometer is usually required for the sensing application. Herein, the orderly-patterned Au-TiO₂ Schottky junction with an Al film that we coupled, which simultaneously works as an optical reflector and conducting layer, can achieve optical sensing of glucose by exciting surface plasmon resonance associated with the environment, and meanwhile can realize glucose detection with direct electrical-signal readout by collecting the photogenerated carriers inside the Au nanostructures and TiO₂ film. When used in optical mode, the designed sensor shows a sensing sensitivity of up to 1200.0 nmRIU^-1 in numerical calculation, and the measured value is 346.1 nmRIU^-1. When used in optoelectrical mode, the glucose sensor under one-sun illumination obtains a sensitivity of 70.0 µAM^-1cm^-2 in the concentration range of 0–10 mM, with a detection limit of 0.05 µM (Signal/Noise=3). Simulation and experimental results demonstrated that the Al-film-coupled Au-TiO₂ Schottky nanojunction can monitor glucose concentration optionally in optical and optoelectrical modes, which presents an alternative route to the miniaturized, portable, and multi-functioned sensors.

Accelerated Polymer Photodegradation

Cynthia Paola Gutiérrez-Castellanos — 2024-04-05

Abstract: This article presents preliminary results of the accelerated degradation of polymers using concentrated solar radiation. For this purpose, a passive solar concentration prototype was designed, which consists of four trapezoidal mirrors placed in the shape of an inverted truncated square pyramid. The mirrors are placed at an angle of 30° respect to the zenith. The prototype has a square base of 46 cm x 46 cm where the polymers to be irradiated are placed and a geometric concentration ratio, CR_g, of 1.89. The mass change was determined after 30 days of exposure to solar radiation, and the temperature variation of some samples as a function of irradiance was obtained. In addition, a computer simulation was carried out using the free access software Energy2D. Some polymers maintained their flexible mechanical properties, such as PET (type 1), others were partially embrittled, while type 2, 5 and 7 polymers were completely embrittled. It was possible to reduce the degradation time of different types of commercial polymers, while polymers exposed to non-concentrated radiation and without exposure remains intact. Embrittled polymers can be used as waterproof material in slabs and pre-cast walls, as well in applications where they are not exposed to solar radiation. On the other hand, the polymers that remained intact must be used in applications with permanent radiation exposure, such as in flower pots, plastic parts for automobiles, etc.