Over the past decade, the cost per kilowatt-hour of solar power has fallen by more than 90 percent, thanks to continuous efforts to reduce costs and improve efficiency in crystalline silicon cells. However, the crystalline silicon technology is quietly approaching its limits, and the industry is beginning to turn its attention to a new material called perovskite.
I. Why Is Crystalline Silicon Nearing the End of Its Lifecycle?
The laboratory efficiency of monocrystalline silicon solar cells has reached about 26.8 percent, while its theoretical limit is approximately 29 percent. In other words, every percentage point of efficiency gained in the past through material purification and minor process innovations now comes at an increasingly high cost. Pushing the limits any further no longer offers a favorable cost-effectiveness ratio.
II. What Exactly Is Perovskite?
Perovskite is not a specific mineral, but rather a class of organic-inorganic halides with a specific crystal structure. It has extremely strong light-absorbing capabilities, a bandgap that can be flexibly adjusted, and—most importantly—can be applied using solution-based methods, much like printing. Theoretically, its manufacturing cost is far lower than that of crystalline silicon, which requires high-temperature crystal growth.
| Comparison Items | Crystalline Silicon (Single-Junction) | Perovskite | Perovskite/Crystalline Silicon Stacked Structure |
|---|---|---|---|
| Laboratory Efficiency | Approximately 26.8% | Approximately 26% (small area) | Has exceeded 33% |
| Manufacturing Costs | High (High-Temperature Process) | Low (solution method) | Chinese |
| Challenges in Mass Production | Pushing the Limits | Stability, Difficulty in Amplification | The combination of the two |
III. A Layered Approach Is the More Realistic Path
It is not easy for pure perovskite to directly replace crystalline silicon, but stacking the two layers together is a clever solution: crystalline silicon absorbs long-wavelength red light, while perovskite absorbs short-wavelength blue light, allowing each to utilize its respective portion of the spectrum. Leading companies have reported certified efficiencies for stacked-cell modules exceeding 34 percent—a level that monocrystalline silicon struggles to match.
IV. The Real Stumbling Blocks Are Stability and Amplification
No matter how impressive the efficiency of small samples is in the lab, ensuring uniformity and consistency when scaled up to the square-meter level is an entirely different matter. Perovskites are sensitive to water and oxygen and are prone to degradation; encapsulation and lifespan (such as T80, which refers to the time it takes for efficiency to drop to 80 percent) are unavoidable hurdles, and the risk of lead migration is also frequently cited as a concern.
So the “next step” for photovoltaics isn’t about one technology replacing another, but rather about multilayer technology raising the efficiency ceiling yet again, thereby creating room for the industry to achieve the next round of cost reductions.