EPFL is a Switzerland-based technical university and research center. EPFL is focused on three missions: teaching, research and technology transfer.
EPFL works together with an extensive network of partners including other universities and institutes of technology, secondary schools and colleges, industry and economy, political circles and the general public.
EPFL does extensive perovskite R&D work and is responsible for many publications and advancements in the field.
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Researchers demonstrate ultrafast nonlinear on-chip polaritonics in perovskite-based systems
Researchers from Russia's ITMO, EPFL in Switzerland, UNAM in Turkey, UK's University of Sheffield and Germany's Technische Universität Dortmund have demonstrated, reportedly for the first time, that halide perovskites can serve as a base for nonlinear on-chip optical components.
Propagation of exciton-polariton wave packets in a waveguide based on halide perovskites. Photo credit: ACS Nano
As an example, they can be used to build ultrafast optical chips and transistors, and, potentially, other integrated optical systems. Unlike other materials, halide perovskites can operate at room temperature and are inexpensive to produce.
New method uses lattice strain to achieve perovskite solar cells with improved stability
Researchers from EPFL, National University of Singapore and Nanjing University of Aeronautics and Astronautics have used lattice strain to lock in rubidium, which helped cut energy loss and push perovskite solar cells to 93.5% of their theoretical efficiency limit. By utilizing the controlled distortion in the atomic structure, this approach not only stabilized the wide-bandgap (WBG) perovskite but also improved efficiency by cutting non-radiative recombination, a major cause of energy loss.
Known for absorbing high-energy light while letting lower-energy light pass, wide-bandgap materials offer major gains in energy capture but are prone to phase segregation, a phenomenon that takes place when different components of the material separate over time, leading to a decline in performance. While adding rubidium to help stabilize the semiconductors has been proposed as a potential way to address the issue, the element often forms unwanted secondary phases, which limits its ability to strengthen the perovskite structure. However, the scientists fine-tuned the material’s composition in a process that involved rapid heating followed by controlled cooling. This created lattice strain, that prevented rubidium from forming unwanted secondary phases and kept it integrated within the crystal structure.
Novel dynamic photochromic strategy could improve the stability and performance of perovskite solar cells
Researchers from the Adolphe Merkle Institute/ University of Fribourg, Université Grenoble Alpes, Forschungsschwerpunkt Organic Electronics & Photovoltaics, Pusan National University, University of Pavia, University of Tübingen, EPFL and Universidad de Antioquia UdeA have developed a novel light-responsive material that enhances the performance and longevity of perovskite solar cells. This innovation could improve the stability of perovskite solar technology and prevent rapid degradation under real-world conditions.
The key innovation is a photochromic compound called SINO, which changes its properties when exposed to light. When integrated into perovskite solar cells, SINO acts as a dynamic protective layer that adapts to changing conditions during operation. This material transforms between two states in response to sunlight, helping to suppress ion migration within the perovskite and facilitate charge extraction.
New approach addresses intrinsic issues of pure-red perovskite LEDs
An international collaboration that includes researchers from China, Switzerland and Saudi Arabia, made progress in the field of perovskite ultra-high-definition (UHD) display technology.
In order to crack the problem of phase instability in pure red CsPbI3 perovskite quantum dots in perovskite UHD display technology, the team examined the strategy of “stress manipulation of epitaxial heterojunction interface”. For the first time, the team used the total solution method to realize large-area in-situ controllable preparation of perovskite vdW epitaxial heterojunctions. This discovery yielded, according to the team, a 'breakthrough in material stability and device performance'. It resulted in a high-efficiency, stable pure red perovskite electroluminescent device (LED). Thus, it provides key technical support for the development of next-generation UHD technology.
Novel mixed-polymer-C60 strategy enables inverted perovskite solar cell with 25.6% efficiency
An international team, including researchers from EPFL, CNR SCITEC, Fujian Normal University, Southern University of Science and Technology (SUSTech) and others, has used an n-type polymeric additive to stabilize C60 molecules for use in inverted perovskite solar cells. The researchers reportedly designed a solar cell with the highest efficiency value ever recorded for perovskite devices based on solution processed C60 electron transport layers.
The team explained that C60 is currently the best-performing type of ETL for perovskite solar cells, although it suffers from “significant” aggregation in solution, which makes a high-cost and complex thermal evaporation method necessary for its development. To solve this issue, it utilized an n-type polymeric additive to stabilize C60 molecules for solution processing. “We introduced an n-type polymeric additive, TPDI-BTI, constructed from the strongly electron-deficient dithienylpyrazinediimide (TPDI) and the imide-functionalized bithiophene (BTI) co-unit and applied it into the C60 ETLs,” the researchers explained. “By controlling the TPDI-BTI addition, we can systematically regulate the ETLs, including film formability and morphological stability, energy levels and electron transport dynamics, intermolecular interacting behaviors and interfacial contacts, and finally, the photovoltaic performance and long-term stability of the cells.”
