Gas sensing is essential for detecting and measuring gas concentrations across various environments, with applications in environmental monitoring, industrial safety, and healthcare. The integration of two-dimensional (2D) materials, organic materials, and metal oxides has significantly advanced gas sensor technology, enhancing its sensitivity, selectivity, and response times at room temperature. This review examines the progress in optically activated gas sensors, with emphasis on 2D materials, metal oxides, and organic materials, due to limited studies on their use in optically activated gas sensors, in contrast to other traditional gas-sensing technologies. We detail the unique properties of these materials and their impact on improving the figures of merit (FoMs) of gas sensors. Transition metal dichalcogenides (TMDCs), with their high surface-to-volume ratio and tunable band gap, show exceptional performance in gas detection, especially when activated by UV light. Graphene-based sensors also demonstrate high sensitivity and low detection limits, making them suitable for various applications. Although organic materials and hybrid structures, such as metal–organic frameworks (MoFs) and conducting polymers, face challenges related to stability and sensitivity at room temperature, they hold potential for future advancements. Optically activated gas sensors incorporating metal oxides benefit from photoactive nanomaterials and UV irradiation, further enhancing their performance. This review highlights the potential of the advanced materials in developing the next generation of gas sensors, addressing current research gaps and paving the way for future innovations.

Silicon carbide (SiC) is widely used in abrasives, heating devices, light emitting diodes and high-power electronics, because of its unique physical-chemical properties including high hardness, high melting point, excellent thermal conductivity, and wide bandgap. In recent years, its color centers have also been used as potential sources of single photons. Given that borides and carbides are refractory materials, we decided to study a heterostructure formed by an n-doped silicon carbide substrate and a layer of tantalum monoboride (TaB) for near ultraviolet (UV) photodetection. It is shown that the addition of TaB creates a rectifying device that can handle currents higher than 300 mA, showing its potential for high-power optoelectronic devices. The detector also has a high responsivity of 2.9 A/W at the free-space wavelength of 405 nm and a fast frequency response of 610 kHz. The high performance of the detector is attributed to the high thermal and electrical conductivity, large bandgap of SiC, and its moderately close match in atomic arrangement with TaB. Such heterostructure offers a simple method to produce high-performance near UV photodetectors operating under hard conditions such as high power, high temperature and corrosive or oxidizing environments.

Photodetectors (PDs) based on 4H silicon carbide (SiC) have garnered significant interest due to their exceptional optoelectronic properties. However, their photoresponse is typically restricted to the ultraviolet (UV) region, with limited light absorption beyond 380 nm, which constrains their utility in visible light detection applications. To overcome this limitation, an efficient photodetector was developed using an alloy with TaC (80%) and Cu (20%) on a 4H n-type SiC substrate, enabling effective light detection at 405 nm. The device exhibited high performance with a high photoresponsivity of 1.66 ${\mathrm{A}\mathrm{W}}^{-1}$ and a specific detectivity of $2.69\times {10}^8$ Jones at 405 nm. The superior performance of the device is ascribed to the enhanced electrical conductivity and optical absorption of the TaC: Cu layer on the 4H SiC substrate, particularly in the near-ultraviolet region. This photodetector combines ease of fabrication with significant performance improvements, expanding the potential applications of 4H SiC in high-temperature optoelectronics. It also introduces a promising pathway for enhancing 4H SiC-based photodetection capabilities across broader spectral ranges.

In this article, a deep and near-ultraviolet photodetector, consisting of an alloy of zirconium diboride (ZrB ₂ ) and Chromium (Cr) deposited on top of an n-doped silicon carbide substrate, is examined. The device has a responsivity of 3.5 A/W at 405 nm with a similar value at 280 nm. It operates at powers below 730 μW and saturates at higher powers. The rise time is about 396 μs.

Ternary chalcogenide-based sulfide materials with distorted morphologies such as BaZrS₃, CaZrS₃, and SrZrS₃, have recently gained much attention in optoelectronics and photovoltaics due to their high structural and thermal stability and compatibility with low-cost, earth-abundant synthesis routes. However, their relatively large bandgaps often limit their suitability for near-infrared (NIR) photodetectors. Here, we conducted a comprehensive investigation of SrHfSe₃, a ternary chalcogenide with an orthorhombic crystal structure and distinctive needle-like morphology, as a promising candidate for NIR photodetection. SrHfSe₃ exhibits a direct bandgap of 1.02 eV, placing it well within the NIR range. Its robust structure, high temperature stability, phase stability and natural abundance make it a compelling material for next-generation, self-powered NIR photodetectors. An in-depth analysis of the SrHfSe₃-based photodetector was performed using SCAPS-1D simulations, focusing on key performance metrics such as J–V behavior, photoresponsivity, and specific detectivity. Device optimization was achieved by thoroughly altering each layer thickness, doping concentrations, and defect densities. Additionally, the influence of interface defects, absorber bandgap, and operating temperature was assessed to enhance the photoresponse. Under optimal conditions, the device achieved a short-circuit current density (Jsc) of 45.88 mA/cm², an open-circuit voltage (Voc) of 0.7152 V, a peak photoresponsivity of 0.85 AW⁻¹, and a detectivity of 2.26 × 10¹⁴ Jones at 1100 nm. A broad spectral response spanning 700–1200 nm confirms its efficacy in the NIR region. These results position SrHfSe₃ as a strong contender for future NIR photodetectors and provide a foundation for experimental validation in advanced optoelectronic applications.

An experiment was conducted at the research field in Gazipur, Bangladesh during winter season of 2014-2015 to determine the effect of different potash fertilizer rates as pre-harvest application viz. K₁ (0 kg-K₂O/ha), K₂  (150 kg-K₂O/ha), K₃  (175 kg-K₂O/ha) and K₄  (200 kg-K₂O/ha) on storability of different potato varieties (V₁= Cardinal, V₂=Courage, V₃=Diamant, V₄=Granola) under natural condition. The potato tubers were stored in a well ventilated room of day and night temperature of (25-30°C) and (20-25°C), respectively. Result revealed that after 135 days of storage, lowest cumulative weight loss was recorded in Granola (12.66%) followed by Courage (21.50%), Diamant (30.84%) and Cardinal (30.84%). The cumulative weight loss was minimum (10.66%) in Granola variety after 135 days of natural storage where the pre-harvest potassium application rate was @ 200 kg-K₂O/ha.