LED generator

We all know LEDs shine when a voltage is applied and current flows through them, but what if we do the oppossite thing? This 0,5 watt LED gets turned into a generator by shining a very powerful beam of UV light towards it, reaching up to 2.2 volts, the same thing occurs with conventional white LEDs. My theory is the electrons get excited by the UV beam, giving them enough potential to "climb" the PN junction and generate a voltage. Just the reverse effect than when using an LED conventionally. This effect can be demonstrated by using daylight or even conventional lamps, but since the UV light is the most energetic of the visible spectrum, the effects will be greater and more noticeable.