Welcome
To The GreenEnergyMaterials-Series
Our Mission
The Green Energy Materials Series (GEMS) aims to promote the work of emerging and established scientists in the field of renewable energy covering subjects such as photovoltaics, energy storage, green fuel production, and more!
With its seminar series, GEMS gives the stage to early career researchers and key players in the field to promote and discuss their work with a community of green energy enthusiasts. The series provides a platform for scientists to give feedback, hear about new trends, current challenges, and important techniques and insights.Â
This series aims to facilitate discussions and to enable deeper insights into phenomena and characterisation techniques. As such, presentations will focus on clearly defined topics covered in depth rather than a list of big achievements.
Presentations will be around 30 minutes long, with copious time for questions. The series will run online via Zoom once every month. Sessions usually start at 4.30pm Berlin time (GMT+1) but might vary depending on the speakers’ location.Â
With the speakers’ permission (an embargo period is possible), the talks will be recorded and uploaded to the GEMS YouTube channel.
We look forward to welcoming all of you to these events,
Vincent M. Le Corre | Simon Kahmann | Bowen Yang
Next Talks - 15 October 2025
IPVF - Institut Photovoltaïque d'Île-de-France, Fr
Metal halide perovskites (MHPs) represent a versatile class of semiconductors that have redefined modern optoelectronics, most prominently through their application in perovskite solar cells. Over the past decade, the power conversion efficiency of these devices has risen dramatically. However, further improvements in both performance and operational stability critically depend on precise control of the interfaces between the MHP absorber and the adjacent charge transport layers.
Photoemission spectroscopy (PES) offers a powerful means to probe the chemical and electronic structure of these buried interfaces, though its application remains challenging due to the complex reactivity of perovskite materials under investigation. In my talk, I will discuss the combined use of synchrotron- and laboratory-based X-ray photoelectron spectroscopy (XPS) to elucidate the interfacial chemistry between MHP films and adjacent oxide charge transport or pre-encapsulation layers. Using hard X-ray photoelectron spectroscopy (HAXPES), we specifically examine atomic-layer-deposited (ALD) SnOâ‚‚ and NiO layers on a double-cation mixed-halide perovskite, revealing the formation of new chemical species and interfacial energy level shifts that can impair device performance.
I will conclude with a broader perspective on the application of PES methods for the characterization of MHP materials, highlighting the dual role of X-ray irradiation as both a source of material degradation and a probe to uncover intriguing self-healing phenomena such as the light- and radiation-induced recovery observed in formamidinium lead bromide films.
Matteo Degani
Department of Chemistry, University of Pavia, IT
Large Organic Cations as Enablers of Record-Breaking Efficiency Through Passivation of Perovskite Solar Cells
The use of large organic ammonium cations has emerged as a game-changing strategy in the field of perovskite photovoltaics, unlocking record-breaking efficiencies and unprecedented operational stability. When deposited onto the surface of three-dimensional (3D) perovskite layers, these bulky cations serve a dual function: they effectively passivate surface and interfacial defects, and they can promote the formation of distinct layers at the interface. Depending on the nature of the cation and the processing conditions, two main scenarios can occur:
the assembly of a thin molecular monolayer, or the crystallization of a low-dimensional perovskite capping layer. While both configurations have demonstrated beneficial effects on device performance, their underlying mechanisms differ significantly and are often misunderstood or generalized in literature. This talk aims to shed light on the fundamental differences between two distinct passivation strategies employed in perovskite solar cells: molecular layer formation and low-dimensional perovskite capping. By examining critical parameters—including cation size, solvent dynamics, and precursor stoichiometry. Representative examples will be presented for both conventional (n-i-p) and inverted (p-i-n) device architectures, highlighting how each passivation approach influences photovoltaic performance and stability.
In the Offing
19 November
Kai Brinkmann
Luis Huerta Hernandez
21 January
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