April 2017

Researchers from Sun Yat-Sen University in China have created a composite of perovskite quantum dots and graphene oxide that can reduce CO₂ when stimulated with light. It is referred to as the first known example of artificial photosynthesis based on perovskite quantum dots.

The team prepared quantum dots ' semiconductor nanoparticles ' of a highly stable cesium'lead halide perovskite, as well as a composite material made of these quantum dots and graphene oxide. Both materials showed an efficient absorption of visible light and strong luminescence. The team used these products to achieve a fundamental step in artificial photosynthesis ' the reduction of CO₂. To simulate sunlight, they used a xenon lamp with an appropriate filter.

In a recent study, EPFL researchers demonstrated how light affects perovskite film formation in solar cells. The team showed that, in the two most common methods used today, light can greatly accelerate the formation of perovskite films and control the morphology of their crystals, influencing the efficiency of the resulting solar cell.

The team used confocal laser scanning fluorescence microscopy and scanning electron microscopy to examine how direct light affects the crystal formation when depositing perovskites in layers, a common stage in building a solar cell. The goal is to ensure homogeneity across the perovskite film, as this is linked to superior photovoltaic performance.

A team from Yale University has discovered a modification of perovskite that can increase the stability and efficiency of perovskite solar cells.

The team explained that light usually generates an exciton in most semiconductor materials, a state where an electron is bound to an electron hole via an electrostatic force. In order to produce usable electricity, the bound electron-hole pair has to be separated into a free electron and free electron hole. This is usually done by electron acceptors, which can overcome the binding energy holding the electron-hole pair together. However, since perovskite semiconductors possess exciton binding energies as low as 16 meV, they generally do not require the use of electron acceptors, which eases the process of generating electricity.

Researchers at The University of Toledo (UT) in the US have developed an all-perovskite tandem solar cell with excellent conversion efficiency. The new kind of device combines two different cells to harvest different parts of the solar spectrum, resulting in increased total electrical power generated.

The team's process enables the fabrication of bottom cells using mixed Sn-Pb perovskite absorbers. The fabrication of the efficient bottom cell, which the researchers say had not been accomplished before, is what is truly innovative about this research work. 'Our all-perovskite solar cells have the so-called four-terminal structure, which stacks a wide-band-gap top cell with a low-band-gap bottom cell. The current all-perovskite tandem cells are limited by the lack of efficient bottom cell'.

Researchers at the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) developed a new perovskite ink with a long processing window that allows the scalable production of perovskite solar cells.

To create a perovskite film, a coating of chemicals is deposited on a substrate and heated to fully crystalize the material. The various steps involved often overlap with each other and complicate the process. One extremely critical stage requires the addition of an antisolvent that extracts the precursor chemicals, and thus create crystals of good quality. The window for this step opens and closes within seconds, which is detrimental for manufacturing due to the precision required to make this time window. NREL researchers were able to keep that window open as long as 8 minutes.

The California Energy Commission, along with the Regents of the University of California, approved a $1.45 million grant to researchers at the University of California-San Diego (UCSD) to support the development of perovskite solar cells.

USCD is home to varied perovskite-based research, among which is work focused on understanding the charge transport and recombination mechanisms in perovskite based solar cells.

Imec, a leading research and innovation hub in nano electronics, energy and digital technologies, and partner in Solliance, announced that it has improved its 4x4cm² perovskite module achieving a certified conversion efficiency of 12.4%.

The module efficiency was measured under long-term maximum power point (MPP) tracking, testifying to its exceptional stability. At Solliance, this perovskite technology is developed with industrially-applicable processes and with a view towards a rapid market introduction of this promising source of renewable energy.

Solar-Tectic has recently been granted a patent titled "Tin Perovskite/Silicon Thin-Film Tandem Solar Cell" as part of a "Tandem Series" of high efficiency and cost effective solar cells by Solar-Tectic, with the potential to surpass the efficiencies of thin-film solar cell technologies such as CdTe, CIGS, and a-Si and replace the current silicon technology.

The patent is reportedly the first for a perovskite layer on crystalline silicon thin-film (tandem), and covers all non-toxic perovskites and inorganic materials.

Researchers at Purdue University and the National Renewable Energy Laboratory have found that certain hybrid perovskites could double the amount of electricity produced without a significant cost increase. This could help in creating efficient solar cells thinner than conventional silicon solar cells, that are also flexible, cheap and easy to make.

The material, a crystalline structure that contains both inorganic materials (iodine and lead) and an organic material (methyl-ammonium), boosts the efficiency so that it can carry two-thirds of the energy from light without losing as much energy to heat.

Researchers at the Korea-based Ulsan Institute of Science and Technology (UNIST) have announced the development of a method to produce perovskite solar cells, demonstrating hybrid organic/inorganic perovskite solar cells of 21.2% efficiency, with good stability ' retaining 93% of the initial performance after 1,000 hours of light exposure.

The study, a collaboration between UNIST and the Korea Institute of Chemical Technology (KRICT), proposes a new manufacturing method for perovskites - the 'hot-pressing method'. The University says that this method allows the production of stable, low cost-high efficiency perovskite solar cells.