By Jason Thompson – Updated Aug 30, 2022
Ben‑Schonewille/iStock/GettyImages
A solar cell is the core component of a photovoltaic panel, converting sunlight into electricity through the photoelectric effect. While commercial cells rely on expensive semiconductor materials, you can create a functional prototype at home using readily available copper and salt water. This simple setup is ideal for classroom demonstrations, science fairs, or powering small DIY devices.
A copper‑salt‑water solar cell demonstrates the photoelectric effect and produces measurable voltage.
Using a propane torch, heat a clean copper sheet until the area exposed to flame glows red hot for at least one minute. With tongs, move the sheet to a fire‑proof surface and repeat the process at several distinct spots. Let the copper cool; the heated zones will appear blackened.
Strip about 1 inch of insulation from each end of a copper wire. Secure one end to a clean, unblackened spot on the copper sheet with an alligator clip. This wire will serve as the cell’s positive terminal.
Dissolve table salt in a cup of water until it no longer dissolves—this is a saturated solution. Apply a few drops of the salt water to the blackened areas of the copper. Surface irregularities will create variations in performance.
Strip the insulation from the other copper wire. Immerse one end into a drop of the salt solution on a blackened spot. Place a weight on the wire to keep it submerged. The other end of this wire will act as the negative terminal.
Connect the free ends of both wires to a small incandescent bulb or a voltmeter. In direct sunlight, the bulb should glow faintly, and the voltmeter will display the voltage generated by the cell.
Operate the propane torch in accordance with the manufacturer’s safety guidelines. Handle hot copper with heat‑resistant tools to prevent burns.
