A team of researchers from China's Chinese Academy of Sciences (CAS), Jilin University and Beijing Institute of Technology, has used perovskite and quantum dots to build an ultraviolet radiation measurement device. 

Measuring the intensity of ultraviolet light in outdoor conditions is important because more intense UV light can lead to faster sunburns and potentially to skin cancer in later years. In this new study, the researchers built a wearable device that can measure ultraviolet radiation in real-time and send the information to a smartphone.

Researchers from The University of Tokyo and Yamagata University have addressed the difficulty in creating blue quantum dots by developing a unique self-organizing approach for producing lead bromide perovskite quantum dots. The research also incorporates cutting-edge imaging technology to characterize these novel blue quantum dots.

Quantum dots (QDs) are used in optoelectronic devices and quantum computing, among other things, and are referred to as "artificial atoms" due to their confined and distinct electronic properties. Quantum dots have characteristics that fall in between those of bulk semiconductors and individual atoms and molecules. Their photoelectric qualities vary depending on their size and shape. Quantum dots (QDs) are considered attractive materials for the emissive constituent of light-emitting diodes (LEDs) due to their high color intensity in a small spectral region, facile color tunability, and notable stability. Moreover, QD-based materials exhibit refined colors, longer lifetimes, reduced production costs, and lower energy requirements compared to typical luminescent materials used in organic light-emitting diodes (OLEDs).

Researchers from the University of Tokyo have made progress with the development of blue-emitting quantum dots, which is seen as highly challenging. They have shown that using a new bottom-up design strategy and self-organizing chemistry can help create a high purity blue-emitting QD material (with a narrow emission spectrum).

The newly developed QDs have a special chemical composition that combines both organic and inorganic substances, such as lead perovskite, malic acid, and oleylamine. The materials self-aligned into a cube of 64 lead atoms. The lead researcher, Professor Eiichi Nakamura, says that "it took over a year of methodically trying different things to find that malic acid was a key piece of our chemical puzzle".

Researchers from the Ulsan National Institute of Science and Technology (UNIST) have teamed up with researchers from Daegu Gyeongbuk Institute of Science and Technology (DGIST) to develop a patterning technique for the production of perovskite nanocrystal displays which are ultra-thin and high-resolution. The production involves a very simple stamp-like printing process that will facilitate the commercialization of the new technique.

Double-layer transfer printing process with RGB pixelated arrays of PeNCs. Image from Science Advances

The technique reportedly enabled the team to produce a display with RGB pixel patterns of 2,550 pixels per inch, which is about 400 percent higher resolution than the latest high-end smartphones.

A research team, led by Prof. Wu Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Dr. Peter C. Sercel from the Center for Hybrid Organic Inorganic Semiconductors for Energy, recently reported the utilization of lattice distortion in lead halide perovskite quantum dots (QDs) to control their exciton fine structure.

Shape or crystal anisotropy in QDs results in energy splitting of their optically bright excitons (bound electron-hole pairs), known as fine structure splitting (FSS). For example, the excitons' FSS can be exploited for coherent control of quantum states for quantum computing, or for polarization-entangled photon-pairs in quantum optics, although for the latter it is important to suppress the magnitude of splitting. Studying FSS usually requires single or just a few QDs at liquid-helium temperature, due to its sensitivity to QD size and shape. Measuring FSS at an ensemble-level, much less controlling it, seems impossible unless all the dots are made to be nearly identical.

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.

UK-based Quantum Solutions started to ship evaluation samples of its next-gen perovskite quantum dots (pQD) X-Ray Scintillators. The company says that these scintillators offer very high sensitivity, high light output, high resolution, low afterglow and can be processed on large areas.

Quantum Solutions started developing these materials in 2020, and already managed to increase the light output (brightness) 10 times over. The company says that this is due to the unique perovskite structure that allows to tune the properties by composition, particle sizes/shapes, ligands, etc. The product already matches the performance of commercial CsI(Tl) and GADOX scintillators. The company is working with key customers in the medical field and non-destructive testing field, and are continuing to develop and customize the product.

Researchers from the Beijing Institute of Technology and MIIT Key Laboratory for Low Dimensional Quantum Structure and Devices have developed perovskite quantum dots microarrays with strong potential for quantum dots color conversion (QDCC) applications, including photonics integration, micro-LEDs, and near-field displays.

QDCC is considered a versatile way to achieve full-color organic light-emitting diodes and micro-light-emitting diodes displays. QDCC provides a wide range of color performance and easy integration. However, conventional QDCC pixels, fabricated by the commonly used method of inkjet printing, tend to be too thin to achieve efficient color conversion. The conventional combination of quantum dots and coffee-ring effects or puddle of particle-laden liquid that occur after evaporation, lowers the light conversion efficiency and emission uniformity in quantum dot microarrays. This also contributes to blue-light leakage or optical crosstalk, where unwanted coupling occurs between signal paths. 

Researchers from Chonnam National University in South Korea, Shivaji University in India, the Belgian research institute KU Leuven and Cardiff University in the UK have built an all-inorganic perovskite solar cell with a terbium doped solar absorber, which reportedly increases thermal stability.

The scientists developed a low-cost and simple hot-air method and also used terbium doping and quantum passivation techniques to stabilize the perovskite phase in the ambient conditions - with all processes carried out in ambient conditions.

This article was extracted from the Perovskite for Displays market report.

Given perovskites materials' unique optical properties, these materials are being intensively researched for both photovoltaic and display applications (as well as several others). In this article we will take a look into the possible application areas in the display industry that can benefit from perovskite materials.

Perovskite QDs

Perovskite-based QDs (PerQDs) are considered a viable Cd-free alternative for display applications, with high PL quantum yields, wide wavelength tunability and ultra-narrow band emission. The main advantages of PerQDs are:

• Low cost
• High performance
• RoHS compliance (despite the lead content)