Perovskite-Info: the perovskite experts

New Energy and Industrial Technology Development Organization (NEDO) and Toshiba have announced the world's largest film-based perovskite photovoltaic module. The module is 703cm² (24.15 x 29.10cm) and achieves a power conversion efficiency (PCE) of 11.7%, overcoming the difficulties of increasing size and efficiency at the same time.

The module was developed using the meniscus printing technology owned by Toshiba and a newly developed printing process. Toshiba developed the printing process for a larger module by controlling the chemical reaction between PbI₂ and MAI on the substrate, using the ink composition as a mechanism. The company has also improved the uniformity of the layer thickness and increased the homogeneity of the crystal layer properties over a larger area, by controlling the process and adjusting the perovskite crystal growth conditions during the printing process. As a result, a PCE of 11.7% has been obtained on a module with an area of 703cm², almost as large as 900cm², the practical a scale.

Researchers at the Tokyo Institute of Technology have developed a barium ruthenium-based (BaRuO3) perovskite catalyst that shows strong activity even at low temperatures (down to 313 K). This is said to be the first catalyst of its kind capable of the selective oxidation of sulfides under mild conditions, with molecular oxygen (O₂) as the only oxidant. The reusable catalyst does not require additives, and so can prevent the formation of toxic by-products. The oxidation of sulfides is a commercially important process with broad applications ranging from chemicals production to environmental management.

The researchers state that BaRuO3 has three advantages over conventional catalysts. Firstly, it exhibits high performance even at 313 K, a temperature much lower than the 373-423 K range reported in previous systems including other ruthenium- and manganese-based catalysts. Secondly, its high rate of oxygen transfer indicates that it has many potential uses; for example, it is applicable to the oxidative desulfurization of dibenzothiophene, which can produce a 99% yield of pure sulfone. Thirdly, the new catalyst is recyclable - the present study showed that BaRuO3 could be reused at least three times without loss of performance.

National University of Singapore researchers have developed a perovskite-based color-enhancement film that may enable richer and more natural colors to next-generation flat-panel electronic displays. The research team is currently working with display companies to commercialize the perovskite color-enhancement film, and hopes to see the technology in consumer electronic products within the next two to three years.

Current commercial display technologies such as OLEDs (organic light-emitting diodes) and QLED (quantum dot light-emitting diodes) can only produce slightly more than 50% of the colors visible to the human eye. This limits the color reproduction that these displays can achieve. A research team from the Department of Chemistry and the Solar Energy Research Institute of Singapore (SERIS) at NUS has developed a color-enhancement film that could allow future display technologies to produce more than 75% of all visible colors. This technology is enabled by using perovskites, which can be tuned by changing its chemical composition to emit light strongly and efficiently in a variety of colors. To make the enhancement films, the research team mixed manometer-sized crystals of the perovskite material with a liquid monomer (precursor of plastics), and triggered a polymerization reaction by illuminating the mixture with white light.

Microquanta Semiconductor has announced reaching "a new world record of 17.3% conversion efficiency for perovskite solar mini-module under newly established testing protocols for perovskite devices". This result was reportedly certified by the international test center Newport Corp.

Under these new protocols, the stabilized 17.3% efficiency rating was for a 7-cell perovskite solar module with designated illumination area of 17.277 cm². The best device reached an even higher number of 17.9% with conventional testing methods. The desired efficiency was achieved by further optimizations of perovskite materials and manufacturing processes. This is the company’s fourth continuous breakthrough regarding efficiency of perovskite solar modules and the first one under new internationally accepted protocols. Since 2017, Microquanta had pushed the efficiency record up from 15.2% to 16%, and then to above 17% before this new accomplishment.

A team of researchers from Peking University and the Universities of Surrey, Oxford and Cambridge have developed a new way to reduce an unwanted process called non-radiative recombination, where energy and efficiency is lost in perovskite solar cells. This technique has reportedly produced "the highest performing inverted perovskite solar cell ever recorded".

The team created a technique called Solution-Process Secondary growth (SSG) which increased the voltage of inverted perovskite solar cells by 100 millivolts, reaching a high of 1.21 volts without compromising the quality of the solar cell or the electrical current flowing through a device. They tested the technique on a device which recorded a PCE of 20.9%, which is said to be the highest certified PCE for inverted perovskite solar cells ever recorded.

Researchers at the University of Maryland (UMD) have identified the impact of the environment on perovskite materials. To understand the physical and chemical processes that lead to degradation, the team exposed these materials to various environmental factors in the lab and measured their response using a technique called “in situ environmental photoluminescence (PL) to temporally and spectrally resolve the light emission within a loop of critical relative humidity (rH) levels.”

“We found that the humidity pathway determines the overall optical response of the perovskite materials, leading to a behavior called luminescence hysteresis, wherein the light emitted from the material depends not only on the current conditions but also the prior ones,” said the team. “Further, we found that the amount of luminescence hysteresis is highly dependent on the ratio between two critical elements constituting the perovskites: Cs and Br.”

Oxford Photovoltaics has reported a new perovskite tandem solar cell record, certified by Fraunhofer ISE at a conversion efficiency of 27.3%. Oxford PV’s latest record for a 1 cm² perovskite-silicon tandem solar, reportedly exceeds the 26.7% efficiency world record for a single-junction silicon solar cell.

Oxford PV recently produced a 1 cm² perovskite-silicon two-terminal tandem solar cell with a verified conversion efficiency of 25.2%, through an ongoing collaboration with Helmholtz-Zentrum Berlin (HZB) and the Photovoltaics and Optoelectronics Device Group at the University of Oxford, led by Professor Snaith.