Perovskite-silicon photovoltaic technology is emerging as a breakthrough in solar innovation, capable of surpassing traditional silicon limits. A new study from the Hong Kong Polytechnic University outlines how tandem cells could soon reach 40% efficiency by tackling key challenges in stability, scalability, and material sustainability.
Toward efficient, scalable, and stable perovskite/silicon tandem solar cells
Perovskite-silicon photovoltaic technology stands as the new frontier of solar research, though the path ahead remains challenging. This tandem structure has already achieved a conversion efficiency of 34%, far surpassing the Shockley–Queisser limit for single-junction silicon cells, yet still distant from its full potential.
A recent study conducted by the Hong Kong Polytechnic University (PolyU) offers a roadmap to close that gap. The team of engineers reviewed the current state of research to identify the main challenges, stability, scalability, and reliability, and to outline the future of perovskite-silicon photovoltaics.
“Although laboratory-scale devices have shown remarkable progress in efficiency, further efforts are required to improve reliability, including minimizing efficiency losses when scaling up from small-area devices to large-area modules,” explained Li Gang, professor of energy conversion technology. “Particular attention should also be paid to ensuring that the manufacturability of materials and methods aligns with industrial standards.”
The challenges of perovskite-silicon photovoltaic cells
Perovskites, with their tunable bandgap, are ideal for multijunction solar applications. In tandem devices, wide-bandgap (1.63–1.7 eV) perovskites typically serve as the top cells, paired with narrow-bandgap absorbers such as silicon, or even other perovskites, as the bottom cells.
The most successful results have come from coupling perovskite with crystalline silicon, achieving a record 34.85% conversion efficiency, surpassing the 32.9% benchmark set by GaInP/GaAs III–V tandem photovoltaics.
However, industrial-scale manufacturing processes for these devices remain undeveloped. Beyond scaling up, improving energy yield, by boosting efficiency and stability, and reducing the levelized cost of electricity through lower production costs are essential.
Unlocking the full potential of perovskite-silicon solar cells requires understanding their two main sources of energy loss:
- Optical losses, primarily caused by reflection and parasitic absorption.
- Electrical losses, due to non-radiative recombination and carrier transport inefficiencies.
“This review discusses these losses in detail and provides guidelines to further enhance tandem efficiency, unlocking their full potential,” the researchers wrote.
Key strategies to reduce losses
To minimize optical losses, the study suggests several approaches:
- Use high-transmittance electrodes, transport layers, and interconnection layers to reduce parasitic absorption.
- Apply antireflective coatings.
- Texture the interfaces.
- Optimize refractive index matching to mitigate reflection losses.
Electrical losses can be reduced by improving the crystalline quality of wide-bandgap perovskites, applying additive engineering for defect control, and developing suitable charge transport materials.
While preliminary outdoor tests have been conducted on perovskite-silicon tandem cells, certified data on their long-term reliability are still limited. To better assess their actual lifespan and commercial potential, researchers recommend rigorous accelerated stability tests following standardized procedures from the International Electrotechnical Commission (IEC).
The study also emphasizes the importance of developing sustainable alternatives to rare or toxic elements and creating efficient recycling or lead-sequestration strategies to ensure environmentally responsible commercialization.
The research, titled “Towards efficient, scalable and stable perovskite/silicon tandem solar cells,” was published in Nature Photonics.
