There are still various materials being researched to be used in solar cells to improve their efficiency. These have high potential but due to certain drawbacks, they are not being commercialized. Perovskite films are one such material. In a recent research, it was discovered that removing concavities can improve stability in perovskite thin film.
Researchers at the Hong Kong University of Science and Technology (HKUST) have gained a new insight into the microstructure of perovskite. They first removed the concavities from the grain surface of perovskite crystals. Then the solar cell prepared, performed better during thermal cycling, MPPT, and damp heat tests.
Through this, scientists have revealed the existence and impact of solar concavities on individual crystal grains of perovskite thin films. In their recently published report, they claimed that the grain boundary induced by thermal-coarsening and biaxial tensile strain induced by grain coalescence trigger the concavities in perovskite materials.
To understand how grain surface concavities affect perovskite films, the team removed them using a surfactant molecule, tridecafluorohexane-1-sulfonic acid potassium. This enabled them to observe how during the formation of the films, strain and ion diffusion are influenced.
As per the report, these cells showed a significant increase in power conversion efficiency. Also, they demonstrated excellent power conversion efficiency retention. This was evident after certain tests:
- Damp heat exposure (660 hours)
- Maximum power point tracking endurance (1,290 hours)
- ISOS-standardized thermal cycling (300 cycles)
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After understanding that removing concavities can improve stability in perovskite thin film scientists discovered these concavities break the structural continuity at the perovskite film interface. Thus, there are plans to improvise the same.
Generally, perovskite has the potential to replace silicon cells in various applications but their long-term stability under light and humidity, plus their thermomechanical conditions remain a barrier.
Source: Elimination of grain surface concavities for improved perovskite thin-film interfaces
