March 2021

Researchers from the Emerging Electronic Technologies Group of Prof. Yana Vaynzof at Germany's Technische Universität Dresden have found that fundamental processes that occur during perovskite film formation strongly influence the reproducibility of the photovoltaic devices.

When depositing the perovskite layer from solution, an antisolvent is dripped onto the perovskite solution to trigger its crystallization. "We found that the duration for which the perovskite was exposed to the antisolvent had a dramatic impact on the final device performance, a variable which had, until now, gone unnoticed in the field." says Dr. Alexander Taylor, a postdoctoral research associate in the Vaynzof group and the first author on the study. "This is related to the fact that certain antisolvents may at least partly dissolve the precursors of the perovskite layer, thus altering its final composition. Additionally, the miscibility of antisolvents with the perovskite solution solvents influences their efficacy in triggering crystallization."

Scientists from the Southern University of Science and Technology in China have developed an automatic light-adjusting electrochromic device (ECD), powered by a perovskite solar cell (PSC), which they say can be used for all-day intelligent-curtains, and advanced electronic displays.

Electrochromic devices are able to reversibly change colors in response to an electric field and generally consist of multi-layer structures with transparent conductors, electrochromic films, ion conductors, and ion storage films. Although these devices are capable of modulating their light absorption under a small driving voltage, the requirement for external electrical supplies causes response-lag.

An international interdisciplinary team, led by MIT, has designed a new approach to narrowing the search for the best candidates for long-lasting perovskite formulations.

Their system has already identified one composition that in the lab has improved on existing versions more than tenfold. Even under real-world conditions at full solar cell level, beyond just a small sample in a lab, this type of perovskite has reportedly performed three times better than the state-of-the-art formulations.

The U.S. Department of Energy (DoE) recently announced an ambitious new target to cut the cost of solar energy by 60% within the next ten years, in addition to nearly $128 million in funding to lower costs, improve performance, and speed the deployment of solar energy technologies.

To that end, the DoE has allocated funding through its Solar Energy Technologies Office (SETO), to support advancing two materials used to make solar cells: perovskites and cadmium telluride (CdTe) thin films.

The U.S. Department of Energy Solar Energy Technologies Office is funding the "American-Made Challenges: Perovskite Startup Prize" - a two-stage, $3 million prize competition designed to accelerate the development and manufacturing of perovskite solar cells by moving world-class research out of the lab and into new U.S. companies.

Competitors who advance from the first stage to the second will receive a $200,000 cash prize. The winners of the second stage will receive $500,000 in cash'a combined total of $700,000'plus $100,000 in technical support vouchers for launching a viable solar manufacturing company with the potential to introduce marketable perovskite products in the United States.

A research team at HZB has used four-dimensional modelling to interpret structural data of methylammonium lead bromide (MAPbBr₃), identifying incommensurable superstructures and modulations of the predominant structure.

Despite intensive research, it was not possible to precisely elucidate the crystal structures of perovskites with their diverse modulations and superstructures as a function of temperature, even for the best-known perovskite compounds such as methylammonium and formamidinium lead halide. Now, the HZB team has analyzed structural data of methylammonium lead bromide (MAPbBr₃) with a novel model. Postdoc Dr. Dennis Wiedemann used a model that takes a fourth dimension into account in addition to the three spatial dimensions. The structural data were measured at a temperature of 150 Kelvin at the University of Columbia.

In 2020, Saule Technologies set out to develop an animal-tracking system, assisted by perovskite-based pv modules, to support the monitoring of European bison in Ukraine. Now, Saule Technologies has reported the development of one of the first real-life applications of perovskite solar cells - powering the telemetry collar for European bison.

The newly-developed solar-powered collar was designed to be more optimal for monitoring big wildlife than commercially available asset-tracking devices, as capturing big, long-lived mammals like bison in order to replace the battery is understandably troublesome and costly. The project was executed in collaboration with WWF (World Wide Fund for Nature) Ukraine and co-financed by the United Nations Development Programme (UNDP) and the Polish Challenge Fund.

A research team, led by Los Alamos National Laboratory, has designed a simple solution for fabricating stable perovskite solar cells that is said to overcome the key bottleneck to large-scale production and commercialization of perovskite solar cells.

A new dipping process using a sulfolane additive creates high-performing perovskite solar cells. Image: LANL

The Los Alamos team, in collaboration with researchers from National Taiwan University (NTU), invented a one-step spin coating method by introducing sulfolane as an additive in the perovskite precursor, or the liquid material that creates the perovskite crystal through a chemical reaction. As in other fabrication methods, that crystal is then deposited on a substrate.

Researchers from the National Renewable Energy Laboratory (NREL) have found that restructuring the way perovskite solar cells are designed can boost their efficiency and increase their deployment in buildings. Their newly proposed architecture for the cells increases the area exposed to the sun by putting the metal contact layers side-by-side on the back of the cell.

Photo by Kevin Prince/NREL

'Taking the materials on top away means you are going to have a higher theoretical efficiency because your perovskite is absorbing more of the sun,' said Lance Wheeler, a NREL scientist .

Researchers from The Hebrew University of Jerusalem and Ben-Gurion University of the Negev in Israel, have studied the two-step deposition of perovskites in mesoporous-carbon-based perovskite solar cells. The team studied the effect of the different deposition parameters on the PV performance and stability.

b) Schematic illustration of the two-step deposition process. The first stage includes dropping of the PbI2 þ PbBr2 solution, the second step includes dipping into the cation solution of FAI þ MABr. Image from article

The influence of the dipping time on the photovoltaic parameters was investigated using charge extraction and intensity-modulated photovoltage spectroscopy (IMVS) measurements. By modifying the perovskite precursors' concentration and the dipping time, a PCE of 15% was achieved. The dipping time in the perovskite deposition of this solar cell structure is critical due to its thickness and mesoporous structure.