Can you turn off the screen while charging?

The screen dims and you have options as to what to display while charging, but is there a way to actually turn the screen off?  Looking at picking up another phone for my mother who regularly listens to audio books while she goes to sleep.  She plugs her phone in every night and has it going all night long.  The light from phone will definately bother her.  There is the option of turning it face down (which will also improve sound), but would also like actual ability to turn screen off itself.