impossible on last version 21.1.20.

>You can create your own materials in the Design tab of the Project window by right clicking on the Materials branch. You can then apply
either an image from a file, a video on the local hard drive or streaming video source from a connected media server. To apply your own
materials to objects, drag and drop them from the Materials branch rather than the Library tab.
The Self illuminated property allows you to create materials that simulate light emitting surfaces such as flat screens or LED panels.

I have the Basic version

Thanks
Alain