Publication date: 16th July 2025
The analysis of fundamental properties, such as energy level positions and bandgaps, are important to enhance our understanding of semiconducting materials such as halide perovskites. Here, most commonly spectroscopic tools such as ultraviolet photoelectron spectroscopy or UV-vis measurements are exploited to measure the density of states or band-to-band transitions.
In this talk, I will show data measured by reflection electron energy loss spectroscopy (REELS), which is a measurement technique that records electrons which are inelastically scattered from a surface. The energy losses can be analyzed to give insights into a variety of surface excitations, most notable for the current study are electronic transitions from conduction to valence band states.
I will show REELS measurements obtained for a wide range of halide perovskites and compare this data to the more conventional analysis performed by UV-vis spectroscopy. The most important difference between these two techniques is the surface sensitivity. Notably, in REELS we can tune the probing depth from around 1 to 10 nm by varying the excitation energy. This allows us to investigate the effect of surface modification on the optical gap of perovskite surfaces. This is particularly interesting for the investigation of the formation of 2D perovskite films on top of 3D layers, for which I will show various examples.
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International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.