August 2022

Researchers at the University of Toronto and the Barcelona Institute of Science and Technology recently reported new solution-processed perovskite photodetectors that exhibit remarkable efficiencies and response times. The photodetectors have a unique design that prevents the formation of defects between its different layers.

The researchers explained that there are applications for which fast photodetection is required in wavelength ranges beyond human vision. "Silicon, the legacy approach—and ideal for electronic readout—does not on its own unite high efficiency with high-speed, as a result of its indirect bandgap, a property of silicon's band structure that produces weak absorption (hence a need for thick silicon) in the near infrared", said University of Toronto's Amin Morteza Najarian. 

A Florida State University research team, led by FSU Professor of Chemistry Biwu Ma, has developed a simple and effective approach to create an efficient and stable blue light from metal halide perovskites.

Scientists have already created highly efficient and stable perovskite-based LEDs for green and red light, but an efficient and stable blue light has been difficult to achieve. Blue light requires a lot of power, and the blue color purity often decreases over time. An efficient and stable blue light is crucial for creating white light.

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.

A team of researchers from from Penn State, the University of California, Oak Ridge National Laboratory and Rutgers University have observed, for what they say is the first time, the unique microstructure of a novel ferroelectric material, enabling the development of lead-free ferroelectric materials for electronics, sensors, and energy storage that are safer for human use.

Ferroelectrics are a class of materials that demonstrate a spontaneous electric polarization as the result of shifts of negative and positive charges that can be reoriented within the material with application of external force. They are especially useful for data storage and memory as they can remain in one polarized state without additional power, making them attractive for energy-saving data storage and electronics.

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.

Researchers have reported a prototype device that could someday replace existing air-conditioners. The device is more environmentally friendly and uses perovskite-based solid refrigerants to efficiently cool a space.

Currently used hydrofluorocarbon refrigerants used in air conditioners and other cooling devices are potent greenhouse gases and major drivers of climate change. This new work has the potential to tackle this issue and offer a greener solution.

Researchers from Ulsan National Institute of Science and Technology (UNIST) have reported the deposition of dense and uniform α-formamidinium lead triiodide (α-FAPbI₃) films using perovskite precursor solutions dissolved in ethanol-based solvent. This addresses the issue of halide perovskites generally not being completely soluble in most non-toxic solvents.

The research team, led by Seok Sang-il, has worked out an ethanol-based perovskite precursor solution by designing a complex compound structure so that perovskites can be dissolved well in ethanol. In their study, the researchers obtained power conversion efficiencies of 24.3% using a TiO₂ electrode, and of 25.1% with a SnO₂ electrode.

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.