Perovskite LED - Page 14

Researchers from the Russian ITMO University have developed effective nanoscale light sources based on a halide perovskite. These nanosources are subwavelength nanoparticles which serve both as emitters and nanoantennas and allow enhancing light emission inherently without additional devices. Moreover, the perovskite enables tuning the emission spectra throughout a visible range by varying the composition of the material. The new nanoparticles are a promising platform for creating compact optoelectronic devices such as optical chips, light-emitting diodes, or sensors.

The nanoscale light sources and nanoantennas have already found a wide range of applications in several areas, such as ultra compact pixels, optical detection, or telecommunications. However, the fabrication of nanostructure-based devices is rather complicated due to the limited luminescence efficiency of the materials used typically as well as non-directional and relatively weak light emission of single quantum dots or molecules. An even more challenging task is placing a nanoscale light source precisely near a nanoantenna.

Researchers at the U.S. Naval Research Laboratory (NRL) Center for Computational Materials Science, working with an international team of physicists, have found that nanocrystals made of cesium lead halide perovskites (CsPbX3), is the first discovered material which the ground exciton state is "bright," making it an attractive candidate for more efficient solid-state lasers and light emitting diodes (LEDs).

The work focused on lead halide perovskites with three different compositions, including chlorine, bromine, and iodine. Nanocrystals made of these compounds and their alloys can be tuned to emit light at wavelengths that span the entire visible range, while retaining the fast light emission that gives them their superior performance.

Researchers at Duke University have developed a method to create otherwise unattainable (or extremely hard to create) hybrid thin-film materials. The new technique could open the door to new generations of solar cells, light-emitting diodes and photodetectors.

The most common perovskite used in solar energy today, methylammonium lead iodide (MAPbI3), can convert light to energy as well as today's best commercially available solar panels. This can even be done using a fraction of the material - a piece 100 times thinner than a typical silicon-based solar cell. Methylammonium lead iodide is one of the few perovskites that can be created using standard industry production techniques, though it still has issues with scalability and durability. To truly unlock the potential of perovskites, however, new manufacturing methods are needed because the mixture of organic and inorganic molecules in a complex crystalline structure can be difficult to make. Organic elements are particularly delicate, but are critical to the hybrid material's ability to absorb and emit light effectively.

Fuji Pigment recently reported that it is researching and developing a new type of perovskite quantum dots. Fuji stated that the half width of their emission spectra is substantially narrower than that of InP; this property could very beneficial to the application of the dots in display materials, LED, bio-imaging and more.

emission spectra of perovskite quantum dots under 420 nm of irradiation light

The chemical composition of perovskite quantum dots are either CsPbX3 or CH3NH3PbX3 (X= Cl, Br, I). Their quantum efficiency is 50'80 % and their half width is 15'39 nm. Their base solvent is either hexane or toluene. However, finding alternative solvents is a challenge that is now being addressed.

EPFL researchers have designed a new type of inorganic nanocomposite that makes perovskite quantum dots (nanometer-sized semiconducting materials with unique optical properties) exceptionally stable against exposure to air, sunlight, heat, and water.

Quantum dots made from perovskites have already been shown to hold potential for solar panels, LEDs and laser technologies. However, perovskite quantum dots have major issues with stability when exposed to air, heat, light, and water. The EPFL team has now succeeded in building perovskite quantum dot films with a technique that helps them overcome these weaknesses.

Researchers at Los Alamos National Laboratory and their partners are creating innovative 2D layered hybrid perovskites that they say can allow greater freedom in designing and fabricating efficient optoelectronic devices. Industrial and consumer applications could include low cost solar cells, LEDs, laser diodes, detectors, and other nano-optoelectronic devices.

They explain that these materials are layered compounds, or a stack of 2D layers of perovskites with nanometer thickness (like a stack of sheets), and the 2D perovskite layers are separated by thin organic layers. "This work could overturn conventional wisdom on the limitations of device designs based on layered perovskites", the team says.

A team of researchers from the University of Macau (UM), Nanjing Tech University, and Nanyang Technological University, Singapore, has announced a significant breakthrough, laying a theoretical foundation for high-efficiency and low-cost perovskite light emitting diode (LED). The research is said to be able to significantly improve the luminous efficiency of perovskite LED and have the potential to advance low-cost, high-efficiency LED displays and LED light sources.

The team discovered that the slow bimolecular recombination that drives 3D lead-halide perovskites' excellent photovoltaic performance is conversely a fundamental limitation for electroluminescence. The team found that the slow bimolecular recombination limitation can be overcome so that high-efficiency electroluminescence can be achieved.

Researchers at Princeton University have developed a technique in which nanoscale perovskite particles self-assemble to produce more efficient, stable and durable perovskite-based LEDs. This advance could speed the use of perovskite technologies in commercial applications such as lighting, lasers and television and computer screens.

The team explains that this technique allows nanoparticles of perovskite to self-assemble to create ultra-fine grained films, an advance in fabrication that could make perovskite LEDs a viable possibility.

EPFL scientists have developed a new perovskite material whose magnetic order can be rapidly changed without disrupting it due to heating. This novel material may potentially be used to build next-generation hard drives.

The EPFL team synthesized a ferromagnetic photovoltaic material. This material is a modified version of perovskite, that exhibits unique properties that make it particularly interesting as a material to build next-generation digital storage systems. The researchers explain that they have basically created the first magnetic photoconductor; This new crystal structure combines the advantages of both ferromagnets, whose magnetic moments are aligned in a well-defined order, and photoconductors, where light illumination generates high density free conduction electrons.

Perovskites that are direct-bandgap semiconductors could be real alternatives to current materials used in LEDs - for applications such as displays and lighting. Perovskite could lead the way towards easy-to-produce, affordable and efficient LED devices. Read out new article Perovskite for LEDs to find out more!