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What are perovskite materials?

Perovskite is a calcium titanium oxide mineral, with the chemical formula CaTiO3. The terms “perovskite” and “perovskite structure” are often used interchangeably, but while true perovskite (the mineral) is composed of calcium, titanium, and oxygen in the form CaTiO3, a perovskite structure is anything that has the generic form ABX3 and the same crystallographic structure as perovskite (the mineral). In a perovskite structure, ‘A’ and ‘B’ are two cations of very different sizes, and X is an anion that bonds to both.Perovskite is found in contact carbonate skarns at Magnet Cove, Arkansas, as well as in altered blocks of limestone ejected from Mount Vesuvius, in chlorite and talc schists in the Urals and Switzerland, and as an accessory mineral in alkaline and mafic igneous rocks

Where do perovskite materials come from?

Perovskite is a calcium titanium oxide mineral composed of calcium titanate (CaTiO3). The name “perovskite” is also applied to the class of compounds which have the same CaTiO3 (XIIA2+VIB4+X2−3) crystal structure, known as the perovskite structure. Many different cations can be embedded in this structure, facilitating the development of diverse engineered materials. Gustav Rose discovered perovskite in the Russian Ural Mountains in 1839 and named it after Russian mineralogist LevPerovski (1792–1856).

How are perovskite materials made?

Perovskite structures have the generic form ABX3, and any crystallographic structure in this form is assigned this name. True perovskite material is made in the form of CaTiO3 from oxygen, titanium, and calcium; however, perovskite also refers to a type of ceramic oxides that have the formula ABX. These compounds are known as alkaline metal halides perovskites, inorganic oxide perovskites, and organic metal halides perovskites. Bridgmanite, a silicate with the formula (Mg, Fe) SiO3, which is the most common mineral in Earth’s mantle, adopts the perovskite structure at high pressure. Compared with SiO68− octahedral units, the SiO44− tetrahedral units in the dominant silica-bearing minerals become unstable as pressure rises. The second most abundant element is possibly the (Mg, FE) Oxide-structured rock salt periclase, under the pressure and temperature conditions of the lower mantle.

How do perovskite materials relate to the quantum dot manufacturing industry?

The rising stars of the photovoltaic industry are perovskite materials. They are cheap to manufacture, easy to make, and extremely effective. Better still, they are new to the scene, so much scope remains to be explored regarding even more powerful solar cells. These materials are used in LED technology as well. For their part, quantum dots (QDs) are a very useful class of semiconductor material with fascinating light-emitting properties, including the ability to adapt to whatever wavelength light is emitted to both LEDs and solar cells.

A new class of quantum dot, based on perovskite materials, is currently under development. Perovskite quantum dots are nanocrystal semiconductors. They are more resistant to defects than metal chalcogenide quantum dots, and they have excellent quantum yields of photoluminescence and high color purity that has already equaled or surpassed metal chalcogenide QDs. Such properties are highly desirable for electronic and optoelectronic applications; thus, perovskite quantum dots have tremendous potential for applications in the real world, including LED displays and solar cells with quantum dots.

Perovskite materials are receiving significant attention from the research community because of their outstanding photovoltaic performance. It has been shown recently that reducing the dimensions of a perovskite crystal structure to a few nanometers creates quantum dots with very high photoluminescence quantum yields and excellent color purity.

These quantum dots are highly tolerant of defects, since they do not require any surface passivation* to retain their high PLQY. (The photoluminescence quantum yield, or PLQY, of a molecule or material is defined as the number of photons emitted as a fraction of the number of photons absorbed.) In the presence of defect and trap locations, their energies are positioned beyond the bandgap and are either located inside the conduction or valence bands. These perovskite material nanocrystals are easy to synthesize in a colloidal suspension and are also easily incorporated into optoelectronic devices using readily available processing techniques, making them a powerful potential contributor to future technologies.

*Passivation is the process of treating or coating a metal in order to reduce the chemical reactivity of its surface. For instance, in stainless steel, passivation entails removing the free iron from the surface of the metal using an acid solution to prevent rust.

Perovskite Quantum Dot Applications

Apparently, perovskite quantum dots are less well researched than other types of quantum dots; however, perovskite quantum dots proved extremely effectivein optoelectronics and nanotechnology for a variety of different applications. For instance, perovskite quantum dots were used to build solar cells with power conversion efficiencies that surpass those of comparable devices based on more traditional nanocrystal semiconductor materials.

Potential applications for perovskite quantum dots include:

  • Light Emitting Diodes
  • Solar Cells
  • Single Photon Sources
  • X-Ray Detectors
  • Lasers
  • Photodetectors
  • Quantum Computing
  • Cell imaging
  • Cancer mapping

Lasers

In 2008, researchers proved that perovskite could generate laser light. LaAlO3 doped with neodymium produced laser emission at 1080 nm. In 2014, experiments showed that mixed methyl ammonium lead halide (CH3NH3PbI3−xClx) cells fashioned into optically pumped vertical-cavity, surface-emitting lasers (VCSELs) convert visible pump light into near-IR laser light with 70% efficiency.

Light-emitting diodes

Due to their high photoluminescence quantum efficiencies, perovskite materials may be good candidates for use in light-emitting diodes (LEDs). However, the propensity for radiative recombination has mostly been observed at liquid nitrogen temperatures.

Photo electrolysis

In September 2014, researchers at EPFL in Lausanne, Switzerland, reported achieving water electrolysis at 12.3% efficiency in a highly efficient and low-cost water-splitting cell, using perovskite photovoltaics.

Most common Perovskites

  • Strontium titanate
  • Calcium titanate
  • Lead titanate
  • Bismuth ferrite
  • Lanthanum ytterbium oxide
  • Silicate perovskite
  • Lanthanum manganite

Classification of Perovskite System

How is Quantum Solutions using perovskite materials?

Quantum Solutions (QS) is a nanotech startup company founded at King Abdullah University of Science and Technology (KAUST), Saudi Arabia. It is a developer and manufacturer of quantum dots for optoelectronic applications: LCD Displays, Light Emitting Diodes, Solar Cells and Photodetectors.

QS Also offers various types of quantum dots (perovskite QDs included) and other advanced materials for scientific use to help the research community explore potential applications for these materials.

Perovskite materials are extremely promising in the field of quantum dots manufacturing. For instance, perovskite materials have demonstrated extensive potential in photovoltaic devices, biological and chemical applications, and displays. The combination of their unique properties makes them useful in real-world applications for the benefit and service of humankind.

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