Perovskites and graphene - Page 2

An international research group, including teams from CHOSE at the University of Rome Tor Vergata, Hellenic Mediterranean University in Greece and others, has developed a large-area perovskite solar panel with graphene-doped electron transporting layers (ETLs) and functionalized molybdenum disulfide (fMoS₂) buffer layers inserted between the perovskite layer and the hole transporting layer (HTL).

The team reported that with increasing temperatures, the module exhibited a smaller drop in open-circuit voltage than commercially available crystalline silicon panels.

Recent research has shown that the incorporation of graphene-related materials improves the performance and stability of perovskite solar cells. Graphene is hydrophobic, which can enhance several properties of perovskite solar cells. Firstly, it can enhance stability and the passivation of electron traps at the perovskite's crystalline domain interfaces. Graphene can also provide better energy level alignment, leading to more efficient devices.

In a recent study, Spain-based scientists used pristine graphene to improve the properties of MAPbI₃, a popular perovskite material. Pristine graphene was combined with the metal halide perovskite to form the active layer of the solar cells. By analyzing the resulting graphene/perovskite material, it was observed that an average efficiency value of 15% under high-stress conditions was achieved when the optimal amount of graphene was used.

The Graphene Flagship, a $1 billion European graphene initiative, has launched a new Spearhead Project called GRAPES, that aims to make cost-effective, stable graphene-enabled perovskite solar panels.

The project will set out to play an essential role in improving Europe's uptake of solar energy projects by improving the stability and efficiency of this technology when deployed on a large scale. As a European Commission funded project, the Graphene Flagship GRAPES initiative has been established to help Europe meet its ambitious sustainability goals.

A team of scientists, led by Professor Feng Yan from Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, and co-workers, recentky developed a novel method to overcome the drawback of grain boundaries (GBs) in perovskites without using defect passivation.

Several 2D materials, including black phosphorus (BP), MoS₂ and graphene oxide (GO), were specifically modified on the edge of perovskite GBs by a solution process. The 2D materials have high carrier mobilities, ultrathin thicknesses and smooth surfaces without dangling bonds. The PCEs of the devices are substantially enhanced by the 2D flakes, in which BP flakes can induce the highest relative enhancement of about 15%.

A research team, led by Dr. Luigi Angelo Castriotta at the at University of Rome Tor Vergata's CHOSE Center for Hybrid and Organic Solar Energy, has reported impressive results on methylammonium free perovskites processed in air, using a scalable technique based on infrared annealing and potassium doped graphene oxide as an interlayer.

The team reached efficiencies of 18.3% and 16.10% on 0.1cm² cell and on 16cm² module respectively, with enhanced stability compares to the standard multi cation reference.

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.