(For an assignment in my English class) Do BlackBerries use solar power?

I’m writing a novella (basically a short novel). In it, one of the the two main characters, along with parts of the Earth, are switched with land corresponding to those same areas from the 1300’s. As you can imagine, communication is a neccesity. Based on aid that I got for my novella, I was told that using BlackBerries (or at least a similar device) that were solar powered-equipped would facilitate communication. My question is: do such devices exist? They can be on the drawing board, but the cutoff date is mid-June of 2007.