DIY solar cell recipe hits 5% efficiency using microwave kiln

Dr. Semiconductor published a video and blog post detailing how to create functional silicon solar cells at home using a microwave kiln. The process starts with a bare silicon wafer, applies a phosphorus-doped glass layer via spin-coating with a TEOS-based solution, then fires it at under 50% microwave power for 30 minutes. After removing the glass layer, gallium-indium and indium contacts complete the cell. The resulting device achieved about 5% efficiency, with identified paths for improvement including clean-room conditions, anti-reflection coating, and better contact formation.

How the DIY cell is fabricated

• Substrate: Bare silicon wafer without existing etchings, purchased off-the-shelf
• Dopant solution: 1 mL TEOS, 0.3 mL 85 wt% phosphoric acid, 5 mL ethanol, 0.25 mL distilled water
• Coating: Solution boiled at low heat for 30 minutes, then spin-coated onto wafer (using a PC fan as spinner)
• Firing: Microwave kiln at under 50% power for 30 minutes; kiln gets hot enough to risk melting silicon
• Finishing: Glass layer sanded or etched off; gallium-indium contact on p-type side, indium on n-type side
• Measured efficiency: ~5%, with noted improvement paths: clean-room, anti-reflection coating, better contacts

Why it matters

The method lowers barriers to experimenting with photovoltaic fabrication, though 5% efficiency remains far below commercial cells. It may interest educators, hobbyists, and researchers exploring low-cost solar manufacturing techniques.