There are problems with two of your ideas, but one of them could potentially work.
Is is possible for a star to radiate in the ultra violet spectrum but not much in the visible light spectrum?
This really isn't possible due to the nature of light. As you may know, the wavelength and frequency of light is inversely proportional - the higher the frequency, the shorter the wavelength. The energy carried by a photon is proportional to its frequency, as you can see in this table on Wikipedia.
Ultra violet light has a higher frequency than visible light, so each photon in the UV range carries more energy than a photon in the visible light range. In order to emit UV light the source has to have more energy available, which means that there is also more energy with which to emit more visible and infrared light.
Something else that makes this not work that stars by their nature contain a variety of elements. Having a variety of elements is why the spectrum a star outputs is very broad. There's also no way to avoid having this variety - the nuclear fusion powering a star creates more elements.
change the visible light to UV like the coating on a black light bulb
This isn't actually how black lights work. Black lights work by blocking visible light with a black paint that lets UV light through. They do a little bit of the reverse though - they include some phosphors that absorb higher-energy UV light (the kind that is more dangerous) and re-emit it as lower-energy UV light. So for the most part, they are equivalent to the idea of blocking visible light and letting UV light through.
any mechanism that would block a lot of the visible light spectrum while still allowing ultra violet to pass through
This could work. As I just mentioned, black lights work by doing this. It's conceivable that you could have a more volcanic planet that tends to spew out some material into the atmosphere that blocks visible light but not UV light (with infrared optionally being let through as well). I don't know what compounds would be best at doing this.
Of course, with most visible light being blocked, plants aren't going to be able to grow. Life on Earth has photosynthetic life at the bottom of almost every food chain. However, on a volcanic planet it's plausible to have a greater abundance of chemicals that can be used in chemosynthesis - using certain chemicals as the basis for energy needed for life instead of using sunlight.
Also, any life that did develop would likely be incapable of seeing what we consider visible light - even with florescence, the amount of light that would be produced would be less than the available UV light. They'd be much more likely to either see infrared and/or UV.