Since OLEDs are still a very intrusive way of changing the color of a room, the idea is to change the color of the wall itself. In this way regulations, restricting the lighting of a room (minimum/maximum amount of light that has to fall on a table) are dealt with more easily and also sunlight can be used to illuminate the room, which would cause problems when being brighter than the light produced by the OLEDs.
We could not find a lot of research in this area, but we could find one research project that uses temperature to affect the state of crystals embedded in the wall (http://www.astc.org/resource/exhibits/stein.htm, http://www.astc.org/resource/exhibits/stein.htm).
This is not particularly helpful for our project since we want to change the color in a rather big area of the building and the amount of heat needed to turn a whole wall red would not be a good idea. But we are confident, that there are other ways to affect the state of (a similar kind of) crystals that would help in our case.