I'm currently working on a portable UV water purification project, but am having a little trouble with the UV emission. I've looked into possibly using an ultraviolet LED array, but the problem with this is that most UV LEDs emit the wrong frequency of UV to be germicidal (~400nm, instead of ~250nm). UV fluorescent germicidal bulbs do work, but they require AC power and an additional ballast for constant current, which would require an inverter and controller circuity. Unfortunately, since I'm looking to power this project off of solar cells, I'm trying to keep the excess circuitry to a minimum. Does anyone have any suggestions?