UVC Emission Devices Based on Alternating Current Inorganic Electroluminescence Using Y2SiO5:Pr3+ Phosphors

Abstract

Ultraviolet C (UVC: 200-280 nm) lighting is urgently required for a number of sterilization applications such as water and air disinfection, food processing, and medical sterilization. Compared to other UVC emission sources, AC-driven inorganic phosphor electroluminescent (EL) devices are appealing due to their wide viewing angle, fast response time, low power consumption, high contrast, simple manufacture, and cost effectiveness. Although the luminance of inorganic phosphor EL devices is typically low, it is sufficient for most low-cost lighting and large-area display applications. In addition, inorganic phosphor EL devices have the advantage of emitting light without generating much heat. In this study, UVC emission was demonstrated through EL devices using a UVC phosphor. Pr3+-doped Y2SiO5 (Y2SiO5:Pr3+) is used for UVC light, Y2SiO5:Pr3+ phosphor shows a broad UVC emission at 280 nm from the f-d transition of Pr3+ ions as well as a sharp red emission at 610 nm from the f-f transition of Pr3+ ions. The phosphors were synthesized in three types to fabricate EL devices. The Y2SiO5:Pr3+ powder, film, and nano-powder formed the phosphor layers of EL devices by screen printing, spin coating, and electrophoretic deposition, respectively. In order to emit UVC light, patterned gold was used for transparent electrodes of the devices instead of conventional indium tin oxide (ITO), which absorbs the UV region. The EL devices were demonstrated in two types: powder EL and electrolyte EL. The fabricated EL devices showed a wide range of UVC emission from 260 nm to 330 nm. Finally, luminescent and electrical analysis of each device was performed to analyze the characteristics.