Title : UV-LED Characterization and design strategies for water treatment
Abstract:
This research paper explores the design, characterization, and testing of a UV-C LED-based lamp for water disinfection. UV-C radiation is an alternative disinfection method that has advantages over chemical disinfectants, including its effectiveness against bacteria, viruses, and protozoa without changing the taste or odor of water. However, UV-C LEDs face challenges, including low external quantum efficiency, which results in higher operating currents compared to visible light LEDs. Excessive self-heating caused by high operating currents is another issue that can compromise the integrity and lifetime of the UV-C LED. The paper discusses the optical characterization of a single UV-C LED without heat dissipation, showing a dramatic drop in optical intensity at high currents. Excessive current consumption and temperature are identified as the primary causes of this reduction, which is attributed to defects in the LED's epitaxial structure. Additionally, the "thermal droop" effect, wherein emitted wavelengths shift towards longer wavelengths as LED temperature increases, is observed. To address the issue, an aluminum heat dissipation plate to stabilize the temperature of the UV-C LED was studied. Furthermore, different bias conditions such as constant current, PWM signal, and High-Current within low time were applied to the E.coli bacteria to evaluate the inactivation effectivity.
