EPFL

Researchers achieve 18.4% efficiency for 4T flexible perovskite-CIGS tandem mini-module

Researchers from Switzerland's Federal Laboratories for Materials Science and Technology (EMPA) and École Polytechnique Fédérale de Lausanne (EPFL) have designed a four-terminal tandem mini-module based on perovskite and copper, indium, gallium and selenium (CIGS) with an aperture area of around 2 cm2, and a geometric fill factor of over 93%.

Image
Processing sequence of flexible NIR-transparent perovskite mini-module

Processing sequence of flexible NIR-transparent perovskite mini-module. Image from RRL Solar

The team reports that the key to efficient flexible perovskite-CIGS tandem modules is the development of near-infrared (NIR) transparent perovskite solar modules on a flexible polymer foil. To achieve these results, the researchers had to overcome the challenges of laser patterning on flexible substrates to realize the first all-laser scribed monolithically interconnected NIR-transparent perovskite mini-modules on polymer film. The perovskite mini-module used in the tandem panel was fabricated on a flexible polyethylene napthalathe (PEN) substrate mounted to a glass substrate in a p–i–n device architecture. This configuration, according to the research team, shows reduced absorption in the NIR region.

Read the full story Posted: Jul 23,2022

Researchers from EPFL and CSEM achieve 31.25% efficiency for tandem perovskite-silicon solar cell

Researchers from the Swiss Center for Electronics and Microtechnology (CSEM) and the École polytechnique fédérale de Lausanne (EPFL) have reported a power conversion efficiency exceeding 30% for a 1 cm2 tandem perovskite-silicon solar cell, which represents a world record for a PV device of this kind. The team achieved an efficiency of 30.93% for a 1 cm2 solar cell based on high-quality perovskite layers from solution on a planarized silicon surface and an efficiency of 31.25% on a cell of the same size and fabricated with a hybrid vapor/solution processing technique compatible with a textured silicon surface.

“These results constitute two new world records: one for the planar and one for the textured device architecture,” the researchers explained, noting that both efficiencies were certified by the US Department of Energy's National Renewable Energy Laboratory (NREL). “The latter approach provides a higher current and is compatible with the structure of current industrial silicon solar cells”. Unfortunately, the researchers did not disclose technical details on how they improved the efficiency of both devices.

Read the full story Posted: Jul 07,2022

Researchers use a 2D perovskite passivation layer as an electron blocking layer in 18.5%-efficient carbon-electrode perovskite solar cell

Researchers from Fraunhofer Institute for Solar Energy Systems ISE, EPFL, Korea Basic Science Institute (KBSI) and Morocco's Abdelmalek Essaadi University have developed a perovskite solar cell with a carbon electrode that achieved 18.5% efficiency.

Electron blocking for 18.5%-efficient carbon-electrode perovskite solar cell imageSchematic diagram of the investigated low-temperature carbon electrode-based PSC with 3D/2D perovskite treated by OAI. Image from study

The solar cell also reportedly retained 82% of their efficiency after 500 hours of continuous illumination. The cell is produced via all low-temperature processes that could likely be scaled into low-cost, large-scale manufacturing ' making the approach attractive despite achieving lower efficiency than record-setting cells.

Read the full story Posted: May 02,2022

EPFL team develops tandem solar cells with 29.2% efficiency

EPFL scientists in Neuchâtel have reported a tandem solar cell that can deliver a certified efficiency of 29.2%. This achievement was made possible by combining a perovskite solar cell with a textured silicon solar cell.

One obstacle the team encountered was finding a way to evenly coat the silicon surface'which is intentionally rough, or textured'with a thin film of halide perovskites. A textured surface is used in order to minimize light reflection. This kind of system can already be found in all commercially available crystalline silicon cells.

Read the full story Posted: Apr 30,2022

Researchers design ionic liquid-based perovskite solar cell with 22.86% efficiency

Researchers from EPFL, Tianjin University, Nanjing Tech University, The University of Tokyo, Shanghai University and Toyota Motor Corporation have used ionic liquids (ILs) with halide anions as additives to improve the performance and stability of a perovskite solar cell.

Ionic liquid-based perovskite solar cell with 22.86% efficiency imageImage from study in Cell Reports Physical Science

Ionic liquids are viewed as a "greener" alternative to organic solvents due to their lower volatility and flammability, as well as to their wide liquid-state window.

Read the full story Posted: Apr 27,2022

Researchers use TiO2 nanoparticles for stable and efficient perovskite modules

A team of scientists, led by Mohammad Nazeeruddin at École polytechnique fédérale de Lausanne (EPFL), has found a way to address the scaling up challenges of perovskites. The scientists have developed an easy solvothermal method to produce single-crystalline titanium dioxide rhombohedral nanoparticles that can be used to build a perovskite film.

The new structure is said to feature a lower amount of lattice mismatches, referring to the "ladder-like" structure of the titanium dioxide nanoparticles. This translates into a lower number of defects, which ensures better electron flow throughout with lower power loss.

Read the full story Posted: Apr 22,2022

Researchers develop low-temperature planar n–i–p perovskite module with 19.1% efficiency

Researchers from the University of Rome Tor Vergata's Centre for Hybrid and Organic Solar Energy (CHOSE), IMEC and EPFL have reported on a solar module with an efficiency of 20.72%, based on tin oxide (SnO2) as an electron transport layer, an organometal halide perovskite layer, organic halide salt phenethylammonium iodide (PEAI) as a passivation agent, and Spiro-OMeTAD as the hole transport layer (HTL).

The international research team presented its low-temperature planar perovskite module with an n'i'p architecture, an aperture area of 11'cm2, and a geometrical fill factor of 91%.

Read the full story Posted: Apr 12,2022

New approach could allow for rapid and low-cost production of perovskite solar cells

An international team of researchers from EPFL, North Carolina State University, Centre for Hybrid and Organic Solar Energy (CHOSE) at the University of Rome Tor Vergata and Uppsala University has demonstrated a technique for producing perovskite photovoltaic materials on an industrial scale, which could reduce the cost and improve the performance of mass-produced perovskite solar cells. The technique is low-cost, simple and energy-efficient.

New technique boosts production of large-scale perovskite solar cells image

'In the lab, researchers produce perovskite photovoltaic materials using a technique called spin coating, which creates a thin film of perovskite on a substrate ' but only on a small scale,' says Aram Amassian, co-corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University.

Read the full story Posted: Jan 30,2022

Researchers use quantum dots to boost perovskite solar cell efficiency & scalability

Researchers at EPFL, Zurich University of Applied Sciences, Ulsan National Institute of Science and Technology, University of Ulsan and Uppsala University have designed an innovative way to increase the performance of perovskite solar cells and maintain it at a high level even at large scales. The new approach replaces the electron-transport layer with a thin layer of quantum dots.

With this new approach, the team, led by Professor Michael Grätzel at EPFL and Dr Dong Suk Kim at the Korea Institute of Energy Research, addressed one of the major obstacles facing the commercialization of perovskite solar cells - the fact that their power-conversion efficiency and operational stability drop as they scale up, making it a challenge to maintain high performance in a complete solar cell.

Read the full story Posted: Jan 21,2022

New isomer passivation method could yield efficient and stable perovskite solar cells

An international team of researchers recently tested a new way of passivating defects in perovskite solar cells. Using a tailored arrangement of atoms, the team managed to overcome challenges related to the formation of a two-dimensional perovskite layer on top of the active cell material, and reach 21.4% conversion efficiency for a 26cm² active area, which is said to be a record for a perovskite device of this size.

Passivation layers, deposited on top of the perovskite material, play an essential role in reducing material defects and unwanted reactions within the material, to improve both performance and stability. One strategy that has been found effective is the use of alkylammonium halides. In many cases these form an additional two-dimensional perovskite layer on top of the perovskite, which can improve device stability but also negatively affect performance.

Read the full story Posted: Nov 10,2021