Homemade Photovoltaics – DIY Silicon PN Junction Solar Cell Testing

Testing of homemade solar cells/PN junction diodes. Some of them output up to .25v open circuit and a few hundred microamps at short. This varies widely because of changes in dopant concentration and wafer size. The higher dopant concentration makes a lower bandgap. Most of these devices have a band gap that is too low to be most efficient for a solar cell. Optimally I would want about 1.4ev. As dopant concentration increases, the wave functions that describe the electrons in both valence and conduction bands start to converge and overlap so the bandgap basically gets broken and the solar cells preform very poorly. I estimate about 1% efficiency on these cells, most likely less.