Perovskites are materials that share a crystal structure similar to the mineral called perovskite, which consists of calcium titanium oxide (CaTiO3).
Depending on which atoms/molecules are used in the structure, perovskites can possess an impressive array of interesting properties including superconductivity, ferroelectricity, charge ordering, spin dependent transport and much more. Perovskites therefore hold exciting opportunities for physicists, chemists and material scientists.
Graphene is a one-atom-thick layer of carbon atoms arranged in a hexagonal lattice. It is the building-block of Graphite (which is used, among others things, in pencil tips), but graphene is a remarkable substance on its own - with a multitude of astonishing properties which repeatedly earn it the title “wonder material”. Graphene is the thinnest material known to man at one atom thick, and also incredibly strong - about 200 times stronger than steel. On top of that, graphene is an excellent conductor of heat and electricity and has interesting light absorption abilities. These varied properties make it a promising and highly researched material, with hopes of incorporating it in many applications: from inks and composite materials, through sensors, solar cells and water filters, to batteries and supercapacitors.
Due to their unique properties, carbon-based nanomaterials have been the center of extensive research efforts in various fields, one of which is the field of photovoltaic energy conversion. In recent years, hybrid metalorganic halide perovskites have become one of the most promising materials for third generation solar cells, with efficiencies that are constantly on the rise.
The incorporation of graphene into perovskite-based solar cells was naturally proposed, and significant work is taking place on this matter. Graphene-based perovskite solar cells are studied in many ways, including hole and electron transport media (HTM and ETM), electrodes, and various approaches aiming at improving the stability of the device. Tandem architectures based on graphene interlayers are also of great interest.
In addition to solar cells, other areas of graphene and perovskite integration include sensors and photodetectors, QDs, nanocatalysts and more.
The latest Perovskite Graphene news:
A team of scientists, led by László Forró from the School of Basic Sciences at the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, has developed a new X-Ray Photodetector based on perovskites and graphene.
Using 3D aerosol jet-printing technology, the team designed a new technique for creating highly efficient x-ray photodetectors that can be easily added to standard microelectronic circuits, creating more powerful medical imaging devices that can deliver better scan qualities.
An experimental graphene-based perovskite solar farm has been operating in Greece for several months, and early results are said to be very promising when it comes to power output and efficiency.
Located at the Hellenic Mediterranean University in Crete and spearheaded by the EU’s Graphene Flagship, the new solar farm consists of nine graphene–perovskite panels with a total area of 4.5m2 and a total output of approximately 261 watt-peak (Wp).
Researchers at Pusan National University, Gwangju Institute of Science and Technology and the Korea Institute of Machinery & Materials (KIMM) in South Korea have tackled perovskite solar cells' stability issues by designing a graphene-based encapsulation technique.
The team introduced a highly flexible and stable graphene encapsulant by adopting the dry transfer method based on a roll-based process.
The performance of photodetectors based on perovskite polycrystalline thin films is still considered to be at a distance from expected values. One reason is that the carrier transport at the interface is easily affected by grain boundaries and grain defects. Many research groups have tried to combine perovskite polycrystalline thin films with high-mobility, two-dimensional materials to improve device performance, and have achieved promising results, but the negative effects of perovskite polycrystalline grain boundaries still remain.
To solve this problem, a team led by Assoc. Prof. Yu Weili from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences, and Prof. GUO Chunlei from the University of Rochester synthesized a low-surface-defect-density CH3NH3PbBr3 microplate through the inverse temperature crystallization strategy. They prepared an effective vertical structure photodetector combining a high-quality perovskite single crystal with monolayer graphene with high carrier mobility.
A UNIST research team has developed an electrode that can significantly improve the stability of perovskite solar cells. UNIST announced that its research team developed “flexible and transparent metal electrode-based perovskite solar cells with a graphene interlayer”.
The team suppressed interdiffusion and degradation using a graphene material with high impermeability, the team said. Team leader professor Hyesung Park commented that the research will greatly help not only solar cells but other perovskite-based flexible photoelectric devices such as LEDs and smart sensors.