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Organic Electronics and Photovoltaics Group

Bild von Beat Ruhstaller

After more than 30 years of R&D and commercialization efforts world-wide, we are now witnessing a wide range of OLED displays in consumer products ranging from mobile phones to 77-inch TVs.

Prof. Beat Ruhstaller, group leader

In the OEPHO group, we work with organic semiconductors and perovskite materials to develop better light-emitting diodes, solar cells and memristors. For this purpose, we maintain an extensive laboratory infrastructure, we develop computer models and use machine learning - and we operate one of the best terahertz spectrometer worldwide.

In the OEPHO group, we mainly deal with organic semiconductors. We create and use simulation software to better understand and predict the behavior of organic light-emitting diodes (OLEDs) and organic solar cells (OPVs). We also use modern methods such as physics-inspired neural networks (PINN) and machine learning (ML). In our in-house lab, we can also fabricate test structures and simple OLEDs and OPV cells. We also deal with measurement techniques and build new measurement devices, often in student projects. Organic crystals are also used in our ultra-wideband terahertz (THz) spectrometer to generate and detect THz waves. In addition to organic semiconductors, we also work with perovskite materials to fabricate, measure, simulate, and better understand solar cells and memristors to drive development at the forefront of cutting-edge research.

SimOEP conference

Laboratory infrastructure

In the OEPHO group, we maintain an extensive laboratory infrastructure for the fabrication and characterization of OLEDs, solar cells and memristors. The pictures show a selection of the equipment.

Custom-built THz spectroscopy & imaging system.

Two glove boxes for the fabrication and measurement of light emitting diodes, solar cells and memristors under nitrogen atmosphere or under exclusion of humidity.

Atomic force microscope (AFM) with Raman spectrometer and Kelvin probe.

Teams in the OEPHO group

THz Photonics Team

Physics-Informed Machine Learning Team

Optoelectronic Materials and Devices Team

Novel Semiconductor Devices Team


In addition to research, OEPHO team members are actively involved in the teaching activities of the School of Engineering. We teach in various Bachelor's programs, in the Master's program and supervise project, Bachelor's and Master's theses, as well as doctoral theses.

Selected Bachelor's theses

Concept study of UV-LED based water disinfection units using flow and radiation simulations

Development of new features in the e-Exercises app with ASP.NET Blazor

A Web App for Teaching Physics with Gamification

Development and characterization of 3D skin tissue models with optical methods

OLED Life-Time Tester

Selected Master's theses

Experimental Validation of an Electro-Thermal Small-Signal Model for Large-Area Perovskite Solar Cells

Hardware-software integration and validation of a compact, time-resolved, optical-pump terahertz-probe spectroscopy system

Optical Modelling of Quantum Dot Films for Display Applications

PhD theses in the OEPHO group

OEPHO group members

Visiting scholars

Nasim Kabir

Ph.D. student at University of Tehran