Researchers at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory have gained new understanding of the happenings inside a hybrid perovskite material in the first few trillionths of a second after it’s hit with simulated sunlight.

The blue and green spheres are atoms. When light hits, electrons start to separate from positively charged “holes,” the first step in creating an electrical current (yellow streaks). Meanwhile, atoms begin to vibrate within the perovskite’s structure.

The research, conducted at the atomic scale, could help explain how electric charges move efficiently through hybrid perovskites following the absorption of light, the crucial first step in generating an electric current. The study used laser pulses that match the intensity of solar radiation, and thus mimic natural sunlight. The authors say their discovery could lead to improvements in the performance of perovskite solar cells and a new way to probe their functionality.

The recent Silicon PV/nPV conference in Lausanne, Switzerland, saw Solliance's announcement on the achievement of a major milestone in perovskite technology for application in future industrial high efficiency tandem photovoltaic cells and modules. Solliance announced realizing a perovskite cell that combines good cell efficiency with a very high near infrared transparency of 93%.

Also at the conference, ECN shows that when this perovskite cell is mechanically stacked on a 6 inch² silicon bottom cell with its proprietary MWT-SHJ (metal-wrap-through silicon heterojunction) design, 26.3% efficiency is achieved, an increase of 3.6% points over the efficiency of the directly illuminated silicon cell laminate.

An international team of researchers led by the University of Cambridge found that a simple potassium solution could boost the efficiency of perovskite-based solar cells, by enabling them to convert more sunlight into electricity. The addition of potassium iodide seems to have a 'healing’ effect on the defects and immobilized ion movement, which to date have limited the efficiency of perovskite solar cells.

Tiny defects in the crystalline structure of perovskites, called traps, can cause electrons to get ‘stuck’ before their energy can be harnessed. The easier it is for electrons to move around in a solar cell material, the more efficient that material will be at converting photons into electricity. Another issue is that ions can move around in the solar cell when illuminated, which can cause a change in the bandgap – the color of light the material absorbs.

A new international study led by chemists at the Georgia Institute of Technology has observed that hybrid organic-inorganic perovskites (HOIPs) possessed a “richness” of semiconducting physics created by what could be described as electrons "dancing" on wobbling chemical underpinnings. That contradicts established semiconductors that rely upon rigidly stable chemical foundations, or quieter molecular frameworks, to produce the desired quantum properties. This could mean that HOIPs may be used in the future as semiconductors with nuanced colors emanating from lasers, lamps, and even window glass.

HOIPs have been reported by the team to be quite challenging to examine, but the researchers from a total of five research institutes in four countries succeeded in measuring a prototypical HOIP and found its quantum properties on par with those of established, molecularly rigid semiconductors, many of which are graphene-based. “We don’t know yet how it works to have these stable quantum properties in this intense molecular motion,” said first author Felix Thouin, a graduate research assistant at Georgia Tech. “It defies physics models we have to try to explain it. It’s like we need some new physics.”