Perovskite-Info: the perovskite experts

A research team, led by University of Minnesota Professor K. Andre Mkhoyan, has made a discovery that blends the best of two sought-after qualities for touchscreens and smart windows—transparency and conductivity.

The atomic arrangement of both the BaSnO3 crystal and the metallic line defect. Image credit UMN

The researchers have observed metallic lines in a perovskite crystal. Perovskites are abundant in the Earth’s center, and barium stannate (BaSnO₃) is one such crystal. However, it has not been studied extensively for metallic properties because of the prevalence of more conductive materials like metals or semiconductors. The finding was made using advanced transmission electron microscopy (TEM), a technique that can form images with magnifications of up to 10 million.

Energy Materials Corporation (EMC), developer of high-speed roll-to-roll manufacturing of solar energy panels, recently announced that it has developed an enabling process to print transparent conductors as part of the scale-up of its inline manufacturing process.

Roll-to-roll printing of metal conductors on Corning Willow Glass (flexible glass) at 60 meters per minute reportedly sets a world speed record for printing flexible electronics on glass. The process surpasses the company's goal of achieving less than 5% loss in the transmission of light though the conductive layer.

Researchers from China have found that adding capsaicin, the molecule that makes chili peppers spicy, could improve perovskite-based solar cells' efficiency and stability.

"Considering the electric, chemical, optical, and stable properties of capsaicin, we preliminarily found that it would be a promising candidate," said Qinye Bao, senior author of the study. However, they needed to do some testing to find the ideal recipe. The researchers found, after executing their experiments, that 0.1 percent capsaicin by weight added to a MAPbl₃ perovskite precursor provided benefits.

Researchers at Linköping University in Sweden have developed efficient blue LEDs based on halide perovskites. The new LEDs could open the door to cheap and energy-efficient illumination.

Schematic of the PeLED structure and the HAADF cross-sectional device image. Image from Nature Communications

Illumination is responsible for approximately 20 percent of global electricity consumption, a figure that could be reduced significantly if all light sources consisted of light-emitting diodes (LEDs). The blue-white LEDs currently in use, however, need complicated manufacturing methods and are expensive, which makes it more difficult to achieve a global transition. LEDs manufactured from halide perovskites could be a cheaper and more eco-friendly alternative for both illumination and LED-based monitors.

Australian scientists at the University of Queensland have designed a perovskite solar cell based on a mix of 2D and 3D salts. By adding a fluorinated lead salt in the processing solution – normally used to form 3D methylammonium lead iodide – they were able to achieve a 21.1% efficiency, an open-circuit voltage of 1.12 V, a short-circuit current of 22.4 mA/cm², and a fill factor of 84%.

The scientists stated that the new cell is more moisture-resistant and durable than “conventional” perovskite cells based on 3D materials alone. The cell is meant to include the advantages of cells based on two-dimensional (2D) perovskites, which generally provide more hydrophobicity and thermal stability than “conventional” 3D structures. But it should also include the benefits of 3D perovskite cells, which can offer strong light absorption, good charge carrier transport, and higher power conversion efficiencies.

The University of Macau (UM) Institute of Applied Physics and Materials Engineering (IAPME) and Nanjing Tech University jointly developed a method to prepare phase-pure quasi two-dimensional (2D) metal-halide perovskites, which could be used for constructing stable perovskite solar cells.

The very low formation energy of the typically used three-dimensional (3D) perovskites accounts for their low stability and hinders the commercialization of perovskite optoelectronic devices. Recent studies show that the dimensionality of deposited perovskites could be reduced from 3D to quasi 2D by introducing an appropriate amount of long organic cations into the precursor solution, which can greatly improve the stability of perovskites thanks to the protection offered by the organic cation layer on the surface. However, such 2D perovskites typically consist of multiple quantum wells with a random well width distribution because of the thermodynamic stability of compounds in the solution. The thick quantum wells and 3D perovskite within the deposited film will still limit the overall stability of the material. Therefore, the deposition of phase-pure quasi 2D perovskite remains a key scientific challenge.

China-based Zhijing Nanotech develops perovskite-QD film (PQDF) technologies for the display industry, and the company demonstrated its first prototypes in 2018.

Perovskite-Info has talked with the company's management, which updated us that it recently concluded a successful pilot with TCL. TCL, in collaboration with Zhijing Nanotech, produced 500 75-inch QD-enhanced LCD TVs (TCL 4K 75M10) with Zhijing's PQDF films. The company reports that the TVs featured a wide color gamut, 147% BT709 - which is higher than most QD TV's on the market, and higher than TCL's original 75M10 TVs.