Ecole polytechnique fédérale de Lausanne (EPFL) - Page 2

Researchers from EPFL, Northwestern University, University of Toronto, Kaunas University of Technology and Toin University of Yokohama recently achieved one of the highest efficiencies ever reported for fully inorganic perovskite solar cells. They also demonstrated for the first time that these cells can operate stably for hundreds of hours, approaching the reliability of commercial silicon solar cells.

Long-term stability is essential for commercialization of perovskite technology. One of the most important methods for reducing defects and protecting the surface from external factors is passivation. This process makes the perovskite surface more resistant to temperature, humidity, and other environmental conditions, thereby extending the device’s lifetime. “Passivation makes the perovskite surface chemically inactive, eliminating the defects introduced during production,” explains Dr. Kasparas Rakštys, from the Faculty of Chemistry at Kaunas University of Technology (KTU) in Lithuania.

Inverted perovskite solar cells (PSCs) can be limited by non-radiative recombination at both the perovskite absorber surface and the perovskite/charge transport layer interface. Researchers from École Polytechnique Fédérale de Lausanne (EPFL), King Abdullah University of Science and Technology (KAUST), Centre d’Electronique et de Microtechnique (CSEM), Potsdam University and IPVF have introduced a bimolecular passivation strategy that simultaneously addresses these two bottlenecks by combining phosphonic acids with piperazinium chloride. 

The phosphonic acids effectively passivate perovskite surface defects, such as lead-related traps, while piperazinium chloride improves the perovskite/electron transport layer interface by enhancing band alignment, introducing a favorable field effect, and homogenizing the surface potential. Together, these complementary effects increase the quasi-Fermi level splitting by approximately 100 mV, substantially improving voltage retention in devices.

An international team led by University College London (UCL) researchers has developed durable new solar cells capable of efficiently harvesting energy from indoor light, meaning devices such as keyboards, remote controls, alarms and sensors could someday be battery free.

The team, which also included scientists from Imperial College London, London South Bank University, EPFL, Phoenixolar and Ordos New Energy Research Institute, explained that despite well-matching indoor illumination spectra, the performance of wide bandgap perovskite solar cells (WB-PSCs) for indoor photovoltaics (i-PV) is hindered by photo-induced halide phase segregation and trap-assisted non-radiative recombination. In this recent work, the team designed a Triple Passivation Treatment (TPT) reassembly strategy to simultaneously suppress bulk and surface defects.

A research team from the School of Engineering (SENG) at the Hong Kong University of Science and Technology (HKUST), Yale University, Lawrence Berkeley National Laboratory and EPFL has introduced comprehensive bio-inspired multiscale design strategies to address key challenges in the commercialization of perovskite solar cells: long-term operational stability. Drawing inspiration from natural systems, these strategies aim to enhance the efficiency, resilience, and adaptability of solar technologies.

The approaches focus on leveraging insights from biological structures to create solar cells that can better withstand environmental stressors and prolonged use. The commercial viability of PSCs is hindered by several operational issues, including inadequate interfacial adhesion, mechanical fragility, and susceptibility to environmental stressors (e.g., heat, moisture, and UV light). These degradation processes occur across various length scales, from picometers to centimeters, and multiscale structural factors can significantly affect the stability and performance of the final perovskite solar cells. 

Researchers at Switzerland's EPFL have developed a bottom-up techno-economic model to analyze perovskite solar module manufacturing costs.

Representative manufacturing route for PSM production. Image from: Renewable Energy

Using this approach, the main bottlenecks for industrial upscaling and mass production for these technologies were identified. Metrics including module manufacturing cost, minimum sustainable price, and levelized cost of energy (LCOE) were evaluated along with the implications of different module replacement strategies on the LCOE.