The thermal stability of perovskite solar panels
The thermal stability of perovskite solar panels can be improved through several advanced material and fabrication strategies aimed primarily at suppressing ion migration and enhancing the perovskite crystal integrity:
Key Methods to Improve Thermal Stability
1. Polymer Grain Encapsulation
Incorporating polymers such as polystyrene-co-polyacrylonitrile (SAN) into the perovskite layer effectively enhances thermal stability by suppressing the migration of organic cations (e.g., methylammonium ions) out of the perovskite structure. This encapsulation at the grain boundaries reduces ionic currents and ion out-diffusion that lead to thermal degradation. For example, methylammonium lead iodide perovskites with SAN showed only a 5–15% decrease in power conversion efficiency after 24 hours at 100 °C, significantly better than pure perovskite films without the polymer. The suppression is attributed to the high immiscibility between the polymer and organic cations, restricting ion movement that typically accelerates degradation at elevated temperatures.
2. Thermoplastic Polymer Additives
Adding thermoplastic polymers during fabrication has been demonstrated as a feasible engineering strategy to improve thermal stability. These polymers can stabilize the film morphology and reduce defects or pathways for ion migration, thus enhancing device durability under heat stress.
3. Ion Migration Inhibition through Crystal Integrity Enhancement
Improving the crystal quality and inhibiting iodide ion migration is crucial. Iodide migration disrupts the perovskite lattice under thermal stress, so strategies that block or limit this migration — for example, by careful compositional tuning or additives — help maintain structural integrity and device performance at higher temperatures.
4. Composition Engineering with Cesium Doping
Introducing a small amount of cesium into the perovskite lattice (around 9% Cs doping) has been shown to improve thermal stability and device performance. Cesium helps stabilize the perovskite structure, making it less prone to thermal degradation and phase segregation, a common problem in organic-inorganic hybrid perovskites under heat.
5. Replacement of Instability-Inducing Components in Device Layers
Using alternative hole transport materials and dopants with higher thermal stability also contributes to improved overall device stability. For example, replacing lithium-based dopants with spiro-based materials in the hole transport layer improves charge transport and thermal robustness, thereby increasing device lifetime under thermal stress.
Summary Table
| Strategy | Mechanism | Effect on Thermal Stability |
|---|---|---|
| Polymer grain encapsulation (e.g., SAN) | Suppresses organic cation migration at grain boundaries | Reduces ionic diffusion, lowers degradation rate at 100 °C |
| Thermoplastic polymer additives | Stabilizes morphology, reduces defects and ion migration paths | Enhances heat tolerance of perovskite films |
| Ion migration inhibition / crystal integrity | Limits iodide and cation migration within perovskite lattice | Maintains crystal structure under heat exposure |
| Cesium doping (about 9%) | Strengthens perovskite lattice, prevents phase segregation | Increases thermal and operational stability |
| Improved device layer materials (e.g., spiro) | Uses thermally stable hole transport layers and dopants | Increases device lifetime under thermal cycling |
These approaches collectively tackle the fundamental instability mechanisms in perovskite solar cells under heat: ion migration, phase instability, and chemical degradation. Combining polymer encapsulation with compositional engineering and optimized device architecture is a promising pathway toward commercially viable, thermally stable perovskite solar panels.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-can-the-thermal-stability-of-perovskite-solar-panels-be-improved/
