Perovskite-Silicon Tandem Cells
Perovskite on silicon converts about 35% of sunlight to power (certified lab record 35.5%), beyond what silicon alone can reach (theoretical limit about 29%).
Open in the interactive tree →Perovskites are crystals with an ABX3 structure that can be made easily from solution. Since the first cell in 2009 (3.8%), single-layer efficiency rose to 27% in under 20 years. Stacked on silicon, the top cell uses blue light and the bottom cell the red.
As of now
The certified perovskite-silicon tandem record is 35.5% (LONGi, announced 14 July 2026, certified by the EU test institute ESTI; small lab cell, area not disclosed), up from 34.85% (NREL, April 2025). Oxford PV shipped the first commercial tandem modules in 2024 (to a US customer, module efficiency about 25%), but large-scale mass production is still missing. The main obstacles are sensitivity to moisture and heat, lead content and proving a 25-year lifetime.
Open steps
- 25-year outdoor stability proof Medium AI leverageLink accelerated ageing tests to years of field exposure for full-size tandem modules, so that a 25-year warranty can be insured.
- Lead containment and lead-free absorbers Medium AI leverageShow that lead stays inside modules through breakage, fire and end of life, and keep developing tin-based or other lead-free absorbers.
- Uniform coating on full-size wafers Medium AI leverageDeposit perovskite layers evenly on full-size textured silicon wafers at production speed; efficiency drops when moving from small cells to modules.
- Wide-bandgap phase stability Medium AI leverageStop halide segregation in the wide-gap top cell under light and heat, which otherwise causes voltage loss over the module's life.
Where AI could help
Medium AI leverage. ML-driven automation speeds the search for durable compositions and recipes, but a 25-year lifetime must be proven in real weather.
- Bayesian optimization of wide-bandgap compositions and additives for stability
- Models that predict lifetime from early accelerated-aging signals
- Self-driving labs for coating, passivation and encapsulation recipes
Shown so far
- In 2025 Materials Advances reported Bayesian optimization combined with automated film processing to improve the durability of triple-halide perovskite films under light and heat, with a 2.5-fold gain in learning rate over grid search. source