Advances in production of novel UV light sources is reviewed. The use of these devices for air and water purification is described, along with necessary validation procedures for verifying the operation of water disinfection systems.

A prototypical design of AlGaN deep ultraviolet (DUV) laser diodes (LDs) on AlN substrates employing tapered electron blocking layer is presented Two-dimensional optoelectronic simulation predicts lasing at a target wavelength of 250 nm Degradation of optical gain associated with spatial separation of electron and hole wave functions inside the active region may be considerably reduced in designs featuring quaternary AlInGaN barriers, by virtue of polarization charge matching A systematic method for selection of polarization-free quaternary barrier compositions is proposed for 250 nm DUV LD designs, accompanied by a sensitivity analysis The selection procedure presented here is readily applied to LDs and light-emitting diodes operating at other wavelengths

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Water and air treatment using ultraviolet light sources

Polarization Matching in AlGaN-Based Multiple-Quantum-Well Deep Ultraviolet Laser Diodes on AlN Substrates Using Quaternary AlInGaN Barriers

Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO2-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO2 was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO2 particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a ...

Integrated photocatalytic filtration array for indoor air quality control.

A new class of semiconductor-based Deep Ultraviolet Light Emitting Diodes (DUV LEDs) is emerging as a disruptive technology for point-of-use water disinfection. Sensor Electronic Technology, Inc. has pioneered compact DUV lamps based on III-Nitride semiconductors (GaN, AlN, InN and their alloys). These semiconductor-based DUV light sources offer narrow spectral power distribution (<12 nm FWHM) with peak emission wavelengths from 227 nm to 340 nm. CW optical output power of up to 100 mW (at 275-280 nm wavelengths) can be achieved using a single, hermetically sealed lamp with a footprint of about 1 square inch. We report on a record-breaking performance of an all-LED point-of-use water disinfection system that utilizes our DUV lamps with peak emission wavelengths in the range from 270 nm to 280 nm. We demonstrated reduction of E. coli bacteria concentration by 5.5 LOG for 0.5 liter/min flow and 3 LOG reduction for 2 liter/min flow.

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Water and air treatment using ultraviolet light sources

Citations

Polarization Matching in AlGaN-Based Multiple-Quantum-Well Deep Ultraviolet Laser Diodes on AlN Substrates Using Quaternary AlInGaN Barriers

References

Integrated photocatalytic filtration array for indoor air quality control.

New UV Technology for Point-of-Use Water Disinfection

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