Here’s a novel approach to harvesting light that uses technology developed at the Vision Laboratory of Columbia University. They've created an image sensor that is also a photoelectric cell, essentially creating a self powered camera. It works by alternating the image capture function with a power capture function - on the same sensor.
This could be extremely useful in remote locations for video monitoring & recording, security applications or for wearable cameras that wouldn't need bulky batteries to power them.
Here’s a link to the Columbia paper that describes the technology. I’m an electronics geek so it’s a fascinating read for me. The abstract and first couple of pages are very readable, even for the non-tech.