i've seen and heard of solar panels for amateur radio work. they are
expensive. they are somewhat fragil. they are also of very low output,
however the input is free.

most hams use them as a long term trickle charger for a big fat storage
battery. usually with a low to medium powered radio.

they can be had (could be had?) from surplus companies. Companies ihave dealt
with include:
All Electronics 818-904-0524 (some time ago)
Jameco 415-592-8097
Digikey 800-344-4539

all these are old phone numbers (ca 1995) and i know at least All nowhas a
web site.

enjoy.
denny