Output blue light evaluation for phosphor based smart white LED wafer level packages.

This study presents a blue light detector for evaluating the output light of phosphor based white LED package. It is composed of a silicon stripe-shaped photodiode designed and implemented in a 2 µm BiCMOS process which can be used for wafer level integration of different passive and active devices all in just 5 lithography steps. The final device shows a high selectivity to blue light. The maximum responsivity at 480 nm is matched with the target blue LED illumination. The designed structure have better responsivity compared to simple photodiode structure due to reducing the effect of dead layer formation close to the surface because of implantation. It has also a two-fold increase in the responsivity and quantum efficiency compared to previously similar published sensors.

Facile Synthesis of Ag Nanowire/TiO2 and Ag Nanowire/TiO2/GO Nanocomposites for Photocatalytic Degradation of Rhodamine B.

This paper investigates the photocatalytic characteristics of Ag nanowire (AgNW)/TiO2 and AgNW/TiO2/graphene oxide (GO) nanocomposites. Samples were synthesized by the direct coating of TiO2 particles on the surface of silver nanowires. As-prepared AgNW/TiO2 and AgNW/TiO2/GO nanocomposites were characterized by electron microscopy, X-ray diffraction, UV/visible absorption spectroscopy, and infrared spectroscopy. Transmission electron microscope (TEM) images confirmed the successful deposition of TiO2 nanoparticles on the surface of AgNWs. The photocatalytic activity of synthesized nanocomposites was evaluated using Rhodamine B (RhB) in an aqueous solution as the model organic dye. Results showed that synthesized AgNW/TiO2/GO nanocomposite has superior photocatalytic activities when it comes to the decomposition of RhB.

Study on the Degradation of Optical Silicone Exposed to Harsh Environments.

Degradation mechanisms of silicone plates under harsh environment conditions are studied in this investigation. Environmental degradation of silicone free form, used as secondary optics in Light Emitting Diode LED lighting lamps and luminaires or any other applications requiring high quality optics being used, has negative implications for the optical performance. Degradation of silicone plates in harsh environment conditions was studied in salt bath and swimming water environments, using different light radiation and temperatures. Samples were exposed to harsh environment conditions for up to 4 months. Optical and chemical characteristics of exposed plates were studied using an Fourier transform infrared- attenuated total reflection FTIR-ATR spectrometer, an integrated sphere, and a Lambda 950 Ultraviolet-Visible UV-VIS spectrophotometer. Results show that 100 °C salt bath exposure had the most severe degrading effect on the optical characteristic of silicone plates. Increasing exposure time in the salt bath at that high temperature is associated with a significant deterioration of both optical (i.e., light transmission and relative radiant power value) and mechanical properties of silicone samples. On the contrary, silicone plates showed a great degree of stability against light exposure (UV at 360 nm and blue light at 450 nm).