This paper presents an extensive literature review on Light-Emitting Diode (LED) fundamentals and discusses the historical development of LEDs, focusing on the material selection, design employed, and modifications used in increasing the light output. It traces the evolutionary trajectory of the efficiency enhancement of ultraviolet (UV), blue, green, and red LEDs. It rigorously examines the diverse applications of LEDs, spanning from solid-state lighting to cutting-edge display technology, and their emerging role in microbial deactivation. A detailed overview of current trends and prospects in lighting and display technology is presented. Using the literature, this review offers valuable insights into the application of UV LEDs for microbial and potential viral disinfection. It conducts an in-depth exploration of the various microorganism responses to UV radiation based on the existing literature. Furthermore, the review investigates UV LED-based systems for water purification and surface disinfection. A prospective design for a solar-powered UV LED disinfection system is also delineated. The primary objective of this review article is to organize and synthesize pivotal information from the literature, offering a concise and focused overview of LED applications. From our review, we can conclude that the efficiency of LEDs has continuously increased since its invention and researchers are searching for methods to increase efficiency further. The demand for LED lighting and display applications is continuously increasing. Our analysis reveals an exciting horizon in microbial disinfection, where the integration of UV LED systems with cutting-edge technologies such as sensors, solar power, Internet-of-Things (IoT) devices, and artificial intelligence algorithms promises high levels of precision and efficacy in disinfection practices. This contribution sets the stage for future research endeavors in the domain of viral disinfection using solar-powered UV LED modules for universal applications.

This paper presents a comprehensive investigation of the efficacy of a 275 nm UV-LEDs system in deactivating two key bacteriophages, MS2 and Phi6, employed as surrogates for non-enveloped and enveloped viruses. This research includes designing and building the 275 nm UV-disinfection system and testing its effectiveness in deactivating the bacteriophages. Our research centers on meticulous control of UV exposure parameters, including precise adjustments to UV dose, irradiance, and exposure time culminating in substantial microbial reduction. Notably, the Phi6 bacteriophage demonstrated a remarkable ~1.26 log reduction factor, corresponding to ~94.50% reduction in viability, achieved at a UV dose of 32.81 mJ/cm ² , Similarly, the MS2 bacteriophage exhibited a log reduction factor of 1.16 and a corresponding 93% reduction, attained at a UV dose of 26.82 mJ/cm ² . These outcomes underscore the considerable potential of the designed 275 nm UV-LED system as a targeted and versatile disinfection technology, bearing substantial implications for real-world applications. Moreover, the prospect of integrating solar cell technology in future research endeavors holds promise for the development of self-sustained and renewable disinfection systems.

Deep UV light has potential and previously been used for deactivating various microorganisms and has shown its germicidal effects. III-Nitride quantum-well based deep UV-LEDs can be used effectively in deactivating pathogens. Several researchers have reported that the deep UV-LEDs are useful in deactivating viruses. However, the data published in the literature seem to be insufficient and inconsistent, thus, necessitating further studies for the use of deep UV-LED to combat COVID virus. This article, therefore, reviews the LED-structure and materials for producing UV-wavelengths for applications in deactivating Coronavirus (SARS-CoV-2). This incorporates the design and simulation-based Nano- Engineered III-Nitride quantum well deep-UV LEDs that will deliver the required wavelength. The design is based on AlGaN/AlN Multiple Quantum wells (MQWs) for deep-UV LEDs capable of producing the wavelength 250 nm < λ ˂ 300 nm. Material combinations and the device-structures aim to achieve the desired wavelengths, spectral and optical power attributes required to deactivate coronavirus. It utilizes nano-bandgap engineering techniques comprising various Al/Ga compositions and AlN epi-layers, and superlattice structures. Using the appropriate number of quantum wells in the device design will achieve the desired wavelengths and power levels.