In photovoltaic research, which configuration yields higher energy conversion efficiency?

• A. Cells made with both silicon and perovskite.
• B. Perovskite-only cells.
• C. Silicon-only cells.
• D. Cells with other materials like cadmium telluride.

Answer: (A)

In photovoltaics, using two absorber materials in a tandem design lets each material capture different parts of the spectrum, boosting overall efficiency. A silicon-perovskite tandem stacks a perovskite top cell with a higher bandgap to absorb blue and green light, while silicon underneath handles red and near-IR light. This complementary absorption increases the total usable light and raises the combined voltage, since the stack benefits from the sum of the subcells’ voltages. Current is shared in the series connection, so the design must balance thickness and bandgap to maximize that current, but with careful optimization this setup typically surpasses the efficiency of either material alone. Perovskite-only cells can be very efficient but stability concerns limit long-term performance; silicon-only cells are mature but have an upper limit for a single junction. Other materials like CdTe offer good performance but generally don’t reach the highest efficiencies seen with silicon–perovskite tandems. That combination yields higher energy conversion efficiency.