they give off an ultraviolet light which excites the phospho
I believe you are describing a fluorescent light, not an LED or Light emitting diode.
LED's do not emit UV light. They emit visible light, and they do not require phosphors for that.
They often do tend to give off a bluish light. Some compensate for this by putting color filters on top of the light. Others naturally emit light in different wavelengths, like yellow, red, green, etc. The difficulty seems to be to get an LED light that emits "white" light in a even way over the entire visible spectrum.