To download mp3 (audio): Click "Download mp3" button
To Cut/Crop mp3: Please use the slider below and click on "Download mp3" button to download the selected part.
Note that video to mp3 conversion output is limited to 10 minutes.
Cuprous oxide is a semiconductor, just like doped silicon, and was one of the first materials experimented with as a solar cell. But its efficiency was found to be so low, around 1%, that researchers stopped trying, though the occasional set of experiments are still done in research labs and papers published. It was also used to make commercially sold diodes and may still be, since that's what a solar cell is - a photosensitive diode.
And before you comment that it's a battery... At 2:30 the cell is getting full sunlight and it is around 10 microamps. At 2:35 I block the sun and it is around 0 microamps. Then at 2:41 I unblock the sun so the cell is getting full sunlight again and it is around 10 microamps again. If it was a battery then the current wouldn't be going back and forth when I block and unblock the sun. So it's solar.
This shows how to make and test a solar cell using a sheet of copper. These solar cells are basically sheets of copper with a layer of cuprous oxide (Cu2O) on them. The cuprous oxide is a semiconductor. You won't get much electricity from it but it's fun to make!