Defect passivation strategy improves perovskite solar cell efficiency

Photo voltaic vitality is a promising approach of lowering our dependence on fossil-fuel-based vitality sources to go for cleaner vitality kinds. Through the years, photo voltaic cells that may harness this renewable vitality have undergone important progress.

Metallic-halide perovskite has gained important consideration as a promising light-absorbing materials for solar cells because of their distinctive optoelectronic properties which allow them to effectively generate vitality from daylight.

A well-liked selection of fabric for constructing excessive energy conversion effectivity (PCE) perovskite photo voltaic cells (PSCs) is polycrystalline formamidinium lead iodide (FAPbI₃) owing to its slim vitality band hole. Regardless of their superior optoelectronic properties and flexibility, polycrystalline perovskites like FAPbI₃ typically endure from defects (imperfections) of their crystal structure that are dangerous to the structural stability and service dynamics, in the end affecting their vitality conversion talents.

To fill this hole, a group of researchers led by Professor Hobeom Kim from the Gwangju Institute of Science and Know-how (GIST) has developed a brand new defect passivation technique, a course of to considerably scale back defects and enhance PCE and stability of perovskite solar cells.

Of their latest examine published on July 4, 2024 in Nature Communicationsthe group reported introducing hexagonal polytype (6H) (completely different structural kinds with the identical composition) perovskite into the cubic polytype (3C) FAPbI₃which led to a exceptional improve of their PCE when in comparison with their counterparts.

However why use 6H perovskite polytype? “A typical approach so far has been to introduce an external chemical reagent to deal with the defect problem. However, bringing in external reagents could directly impact the crystalline quality of the perovskite during crystal growth, so our work does not rely on such stabilizers. Instead, we employ a chemically identical polytype of perovskite, 6H polytype containing a corner-sharing component that effectively suppresses the formation of defects in perovskite,” explains Prof. Kim.

The researchers included 6H perovskite into FAPbI₃through the use of extra of lead iodide and methylammonium chloride, thereby making a part that intervened with the dominant defect website (halide vacancies, V_I⁺) of α-phase cubic polytype (3C) FAPbI₃.

They discovered that the 6H section improved the structural integrity and service dynamics of FAPbI₃. This led to an ultralong service lifetime of better than 18 microseconds, PSCs with PCEs of 24.13% and a module with PCEs of 21.92% (licensed power conversion efficiency of 21.44%) with long-term operational stability.

The researchers steered that the 3C/6H hetero-polytypic perovskite design is perhaps the closest to the perfect configuration of a polycrystalline perovskite movie. The examine demonstrated how engineering defects in perovskite can speed up the event of superior PSCs for private and industrial makes use of, comparable to in rooftop solar panelswearable electronics, and moveable chargers.

“Perovskite solar cells offer a transformative solution for achieving carbon neutrality and addressing global warming. Their efficiency, versatility, and reduced environmental impact make them an essential component in the transition to a sustainable future,” concludes Prof. Kim.