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The Scanning Probe Microscopy Laboratory was founded in 2017 by Alex Redinger in a framework of an FNR consolidator grant. 

The group focuses on the study of the surface of two types of thin film solar cells, namely Cu(In,Ga)Se2 (CIGSe) and hybrid organic inorganic perovskites, as well as 2D materials. We combine scanning probe microscopy techniques in ultra-high vacuum such as Scanning Tunneling Spectroscopy (STS) and Kelvin Probe Force Microscopy (KPFM) and photoluminescence imaging (PL/TRPL) to access the electrostatic and optoelectronic properties at the surface of semiconductors.

Latest News

  • 08/12/2023

New PhD position avaiable in my group:

Please use the following link to apply.

few more details on the project. This is an FNR funded project focussed on a material class named CIGSe, which is used to make very effcient thin film solar cells. In this project, there will be two PhD positions available. One in the group of Prof. Susanne Siebentritt and one in my group. We will receive epitaxially grown CIGSe absorbers from the Siebentritt group and will study the cleaved surfaces of CIGSe. This will be done with AFM, KPFM and STM. The goal is to atomically resolve the CIGSe cross section, identidy defects and disorder in the material. Furthermore, we want to study full devices in cross section via KPFM. The measurements will be carried out in UHV with an Omicron VT system and with a Park Systems AFM system, that was recently aquired in our department and that will arrive early next year.
I need a very motivated student with an excellent background in solid state physics and semiconductors. Previous experience with scanning probe techniques are certainly an advantage.

Looking forward to your application
  • 01/12/2023

New paper in Energy & Environmental Science;

Understanding and decoupling the role of wavelength and defects in light-induced degradation of metal-halide perovskites (

Why do halide perovskites become unstable and decompose when illuminated. One important aspect is excess PbI2. We show how PbI2 acts as seeds for decomposition, we show that the light induced deterioration depends on the wavelength. Experimental data is supplemented with DFT calculations to better understand why and under which circumstances the perovskites decompose. Samples from EPFL, DFT calculations performed in the Tkatchenko group at UL, HIM SIMS mapping performed at LIST, XPS, KPFM, STM performed by the SPM group. 
  • 12/05/2023

Recent Publications

December 2023

Understanding and decoupling the role of wavelength and defects in light-induced degradation of metal-halide perovskites

Jeremy Hieulle, Anurag Krishna, Ariadni Boziki,  Jean-Nicolas Audinot,  Muhammad Uzair Farooq,  Joana Ferreira Machado,  Marko Mladenovic´, Himanshu Phirke, Ajay Singh, Tom Wirtz, Alexandre Tkatchenko, Michael Graetzel, Anders Hagfeldt  and Alex Redinger

Energy Environ. Sci. (2023)

August 2023

Mitigating the Heterointerface Driven Instability in Perovskite Photovoltaics

Anurag Krishna, Viktor Skorjanc, Mathias Dankl, Jeremy Hieulle, Himanshu Phirke, Ajay Singh, Essa A Alharbi, Hong Zhang, Felix Eickemeyer, Shaik M Zakeeruddin, GN Manjunatha Reddy, Alex Redinger, Ursula Rothlisberger, Michael Gratzel, Anders Hagfeldt

ACS Energy Lett. 2023, 8, 8, 3604–3613

May 2023

Light Makes Right: Laser Polishing for Surface Modification of Perovskite Solar Cells

Mayank Kedia, Monika Rai, Himanshu Phirke, Clara A Aranda, Chittaranjan Das, Vladimir Chirvony, Stephan Boehringer, Małgorzata Kot, Mahdi Malekshahi Byranvand, Jan Ingo Flege, Alex Redinger, Michael Saliba

ACS Energy Lett. 2023, 8, 6, 2603–2610

May 2023

Nanoscale Surface Analysis Reveals Origins of Enhanced Interface Passivation in RbF Post Deposition Treated CIGSe Solar Cells

Christian Kameni Boumenou, Himanshu Phirke, Jonathan Rommelfangen, Jean‐Nicolas Audinot, Shiro Nishiwaki, Tom Wirtz, Romain Carron, Alex Redinger

Adv. Funct. Mater.2023, 33, 2300590

August 2022

Coevaporation Stabilizes Tin-Based Perovskites in a Single Sn-Oxidation State

Ajay Singh, Jeremy Hieulle, Joana Ferreira Machado, Sevan Gharabeiki, Weiwei Zuo, Muhammad Uzair Farooq, Himanshu Phirke, Michael Saliba, Alex Redinger

Nano Letters 22 (17), 7112-7118

July 2022

Surface Passivation and Detrimental Heat-Induced Diffusion Effects in RbF-Treated Cu(In,Ga)Se2 Solar Cell Absorbers

Amala Elizabeth, Sudhir K Sahoo, Himanshu Phirke, Tim Kodalle, Thomas D Kühne, Jean-Nicolas Audinot, Tom Wirtz, Alex Redinger, Christian A Kaufmann, Hossein Mirhosseini, Harry Mönig

ACS Applied Materials & Interfaces 14 (29), 34101-34112

June 2022

The impact of strain on growth mode in chemical vapor deposited mono- and few-layer MoS2

J Rommelfangen, S Reichardt, V Ben Chu, L Wirtz, PJ Dale, A Redinger

AIP Advances 12 (6), 065010

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