Perovskite Solar - Page 57

Scientists from Switzerland's EPFL and the Toyota Motor Corporation have prepared a detailed analysis of the projected costs of designing and operating a 100 MW perovskite solar cell production line in various locations, taking under consideration factors like labor and energy costs as well as all materials and processing. The team found that perovskite PV could be cost-competitive with other technologies even at much smaller scale, but noted that this still depends on the tech proving its long-term stability, and impressive achievements in research being successfully transferred to commercial production.

While perovskite materials have been repeatedly demonstrating their potential for low-cost, high-efficiency solar energy with lower energy fabrication compared to silicon PV technology, there are still many different possibilities regarding the form these commercial products could take, and the materials they could contain - with more than one option that could prove commercially viable.

Researchers at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL), in collaboration with scientists from the University of Toledo, the University of Colorado–Boulder, and the University of California–San Diego, have announced a technological breakthrough and constructed a perovskite solar cell with the dual benefits of being both highly efficient and highly stable.

A unique architectural structure enabled the researchers to record a certified stabilized efficiency of 24% under 1-sun illumination, making it the highest reported of its kind. The highly efficient cell also retained 87% of its original efficiency after 2,400 hours of operation at 55 degrees Celsius.

Scientists at the University of California at Berkeley and the US Department of Energy's Lawrence Berkeley National Laboratory have developed a perovskite-structured ferroelectric compound that might be suitable for the production of lead-free perovskite solar cells.

“The new ferroelectric material – which is grown in the lab from cesium germanium tribromide (CsGeBr₃ or CGB) – opens the door to an easier approach to making solar cell devices,” the team said. “Unlike conventional solar materials, CGB crystals are inherently polarized, where one side of the crystal builds up positive charges and the other side builds up negative charges, no doping required.”

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory and Purdue University have developed a machine learning method for screening many thousands of compounds as solar absorbers. Argonne's Maria Chan and Purdue's Arun Mannodi-Kanakkithodi, who led the study, chose to work with a form of artificial intelligence (AI) that uses a combination of large data sets and algorithms to imitate the way that humans learn. It learns from training with sample data and past experience to make ever better predictions.

The team used their machine learning method to assess the solar energy properties of halide perovskites. "Unlike silicon or cadmium telluride, the possible variations of halides combined with perovskites are essentially unlimited," said Chan. "There is thus an urgent need to develop a method that can narrow the promising candidates to a manageable number. To that end, machine learning is a perfect tool."

Scientists from China's Huaqiao University and Henan Normal University have developed a controllable moisture treatment for perovskite films that can promote the mass transportation of organic salts. The films were used to fabricate a 0.2 cm² perovskite solar cell that was able to retain 80% of its initial efficiency after 1200 h.

The group investigated the effects of moisture in the air on the intermediate and final perovskite films in solar cells and developed the controllable moisture treatment that relies on a series of nitrogen (N₂)-protected characterization techniques.

Researchers at Soochow University, Sichuan University and Empa (Swiss Federal Laboratories for Materials Science and Technology), recently devised a new strategy to create high-quality perovskite absorbers with grains in the micrometer scale and prolonged carrier lifetimes. This new strategy is based on a close-space annealing (CSA) process, a heat-based technique that can be used to change a material's chemical properties.

According to the team, controllable crystallization plays a crucial role in the formation of high-quality perovskites. The researchers reported a universal CSA strategy that increases grain size, enhances crystallinity and prolongs carrier lifetimes in low-bandgap (low-Eg) and wide-bandgap (wide-Eg) perovskite films. The CSA strategy devised by the team is universal, as it can be applied to perovskites with various bandgaps to produce high-quality absorbers with enlarged grains and longer carrier lifetimes. As part of their recent study, the team demonstrated its generalizability by successfully using it to prepare absorbers based on perovskites with different chemical compositions.

Scientists from Taiwan's Industrial Technology Research Institute (ITRI) and National Yang Ming Chaio Tung University recently demonstrated a way to produce high-purity lead-iodide, as a precursor material for a perovskite solar cell. The team used temperature to better control the orientation of crystals, and managed to show much higher efficiencies when the precursor was used to fabricate a perovskite layer and subsequently a working solar cell.

The team worked on the fabrication of lead-iodide (PbI₂), an element used in many of the highest-performing perovskite solar cells produced to date. They built on earlier research that has shown the purity and formation of this material could be a key factor in performance once it is integrated into a solar cell. The group’s recent work demonstrates how the crystalline structure and orientation of PbI₂ have a significant impact on cell performance. The researchers also introduce a simple way to control this using temperature during synthesis. 

Researchers from the University of Melbourne, Monash University and IEK-5 Photovoltaik in Germany have developed a large-area laser beam induced current microscope that has been adapted to perform intensity modulated photocurrent spectroscopy (IMPS) in an imaging mode. The new imaging tool could reportedly spot previously undetectable defects in solar cells.

The team's IMPS microscopy was used to study the spatial dependence of moisture-related degradation in a back-contact PSC. Using diffusion-recombination theory, the researchers modeled the IMPS response from which ambipolar diffusion length maps can be extracted from low-frequency experimental data. Apart from this important metric, they illustrated how other frequency bands can be used to study the degradation of a PSC.

Great Wall Holdings (GWH) has entered a contract to build the headquarters and a perovskite base for its spin-off company UtmoLight in Wuxi, China. 

The company signed an agreement with local authorities of Wuxi’s Xishan Economic & Technological Development Zone to invest 3 billion yuan (around USD$442.2 million) in the UtmoLight project. The new headquarters and perovskite innovation industrial base will reportedly house 'the world’s first GW-grade perovskite photovoltaic module and BIPV production line'. The production line of perovskite quantum dot will feature a production capacity of 100 tonnes per year. GWH expects to see an annual production value of 2.5 billion yuan ($368.5 million) after the base is up and running.

University of Cambridge scientists have developed perovskite-based floating ‘artificial leaves’ that generate clean fuels from sunlight and water. The team expects these could eventually operate on a large scale at sea. The ultra-thin flexible devices take their inspiration from photosynthesis. Since the low-cost, autonomous devices are light enough to float, they could be used to generate a sustainable alternative to gasoline without taking up space on land.

A floating artificial leaf which can generate clean fuel from sunlight and water – on the River Cam near King’s College Chapel in Cambridge, UK. Image credit: Virgil Andrei, from: Scitechdaily

Outdoor tests of the lightweight leaves on the River Cam showed that they can convert sunlight into fuels as efficiently as plant leaves. River Cam is the main river flowing through Cambridge in eastern England, and the testing occurred near iconic Cambridge sites including the Bridge of Sighs, the Wren Library, and King’s College Chapel.