Doctoral Researchers

Amram Al-Ashouri

Optimization of Perovskite Single Junctions for Hybrid Tandem Solar Cells

Supervised by: 
Prof. Dr. Bernd Rech and Prof. Dr. Steve Albrecht

Pascal Becker

Insitu-Röntgenabsorption an Perovskit-Dünnschichten

Supervised by:
Prof. Dr. Susan Schorr and Dr. Thomas Unold

Lucas Bodenstein-Dresler

X-ray and electron spectroscopy - based insights into perovskite solar cells layer stacks

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
Prof. Dr. Marcus Bär

Sebastian Caicedo-Davila

Advanced Halide perovskite materials and device characterization

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
PD Dr. Daniel Abou-Ras

Laura Canil

Self-assembling at the interface in perovskite solar cells

Supervised by:
Prof. Dr. Antonio Abate

Pietro Caprioglio

Deposition of Perovskite Films on Textured Surfaces

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
Prof. Dr. Bernd Rech,  Prof. Dr. Steve Albrecht and Prof. Dr. Dieter Neher

The Ph.D. project aims in the realization of monolithic perovskite/silicon tandem structures on textured wafer surfaces that are utilized for optimum light management. The doctoral candidate will develop strategies to process inorganic-organic perovskite films and the selective contacts on top of various textured surfaces that are used for silicon photovoltaics. To realize this project, new film-processing techniques will be developed by the student In addition, fundamental physical understanding of the film formation will be realized by utilizing various analytical methods as basis for optimization of the tandem solar cell device performance.

Marion Flatken

Stable and efficient lead-free halide perovskite solar cells

Supervised by:
Prof. Dr. Antonio Abate

Hannah Funk

Correlative microscopy and spectroscopy on halide perovskite solar cells

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
PD Dr. Daniel Abou-Ras and Prof. Christoph T. Koch, PhD

Max Grischek

Advancing inorganic perovskite compositions for highly efficient top-cells in tandem devices

Supervised by:
Prof. Dr. Steve Albrecht and Dr. Lukas Kegelmann

Mahmoud Hussein

Doping Tin-based perovskite solar cells

Supervised by:
Prof. Dr. Antonio Abate and Prof. Dr. Andreas Taubert

Katrin Hirselandt

Skalierbaren Schlitzdüsen- und Tintenstrahldruckprozessen für die großflächige Abscheidung hybrider Perowskit-Halbleiter und selektiver Kontaktschichten

Supervised by:
Prof. Dr. Bernd Rech and Dr. Eva Unger

Ivona Kafedjiska

p-conductors for perovskite-CIGSe tandem solar cells

Supervised by:
Prof. Dr. Bernd Rech and Dr. Iver Lauermann

Jinzhao Li

will be handed in later

Supervised by:
Dr. Eva Unger

Manaswita Kar

Electronic structure and band gap tuning of perovskites from first principles

Supervised by:
JProf. Dr. Thomas Körzdörfer,  Prof. Dr. Peter Saalfrank and Prof. Dr. Norbert Koch

Organometallic perovskite solar cells have revolutionized the field of emerging photovoltaics, rapidly surpassing the performance of the conventional dye-sensitized and organic technologies. In addition to their favorable optoelectronic properties, perovskites are structurally and compositionally very flexible, which makes them ideal candidates for the application in tandem solar cells. Efficient tandem architectures, however, require the combination of materials with precisely tuned optoelectronic properties. Despite the extremely fast progress in recent years, relatively little is understood about the key electronic properties of perovskite-based solar cells and how they can  be specifically tuned, e.g., by changing the compositional or structural properties.

The PhD-student working on this project will perform in-depth theoretical investigations of the electronic structure of perovskite materials using state-of-the-art electronic structure methods. The aim is to clarify how the key electronic properties of perovskites, such as the optical band gap, can be tuned by changing the composition and/or structures. It will be of central importance to gain a profound understanding of the key ingredients that affect the electrical, optical, and transport properties of these perovskite materials, thus, opening the way to the design of new and improved materials.

In terms of the methods, the student will mainly use density functional theory (DFT), time-dependent density functional theory (TD-DFT), and many-body perturbation theory calculations in the GW approximation (and beyond). Experience with any of these methods or, more generally, with electronic structure calculations for periodic systems would be helpful, yet not strictly required. While the focus of this work is theoretical, the student will be working closely together with the experimental projects associated with the graduate school. Not only will the insights from this theoretical work lead to a better understanding of the key electronic properties of perovskites, but its outcome will also yield important input towards the design of novel perovskite materials and help to identify ideal candidates for tandem cell applications.  In summary, this is a very challenging but also very rewarding project, requiring an enthusiastic PhD candidate with a sound training in theoretical/computational physics or chemistry and interest in theoretical materials science.

Hans Köbler

Investigation and improvement of the long-term stability of solution-processed metal halide perovskite-based solar cells

Supervised by:
Prof. Dr. Bernd Rech and Prof. Dr. Antonio Abate

Eike Köhnen

Development of transparent contacts for hybrid tandem solar cells

Supervised by:
Prof. Dr. Bernd Rech and Prof. Dr. Steve Albrecht

Frederike Lehmann

Synthese und Charakterisierung von Hybrid-Perowskiten: Variation der Komponenten

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
Prof. Dr. Susan Schorr and Prof. Dr. Andreas Taubert

Metal-organic hybrid perovskites based on lead halides have attracted tremendous interest for use in solar cells. One key advantage of these materials is their high flexibility as far as synthesis is concerned and the resulting tuneability of their physical properties. As of now, however, only a fairly small number of variants of these perovskites has been described in the literature. There is thus a need to evaluate the variability, the chemical adaptability and tuning of these perovskites in much more detail to enable the fabrication of advanced solar cells and other optoelectronic devices.
 
The central goal of the PhD thesis therefore is the synthesis of novel perovskites derived from existing prototypes and model compounds with the special aim to improve and scale up the synthesis to larger amounts of material, once suitable candidate materials have been identified. The project will focus on adapting the optical and electronic properties such as the band gap by exploring different strategies like doping, replacement of specific elements of the metal-organic perovskites by other chemical elements or building blocks. The resulting materials will be investigated for their structures and physical properties along with their potential for use in solar cells.

Dorothee Menzel

Development of charge caerier-selective hetero contacts

Supervised by:
Prof. Dr. Bernd Rech und Dr. Lars Korte

Hampus Näsström

Capturing intrinsic parameters defining the solar energy conversion efficiency

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
Dr. Eva Unger and Dr. Thomas Unold

Gopinath Paramasivam

Scaling Perovskite Semiconductor Deposition with solution-based Methods

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervised by:
Dr. Eva Unger and Dr. Florian Mathies

Nga Phung

Active materials and interfaces for stable perovskite solar cells

Supervised by:
Prof. Dr. Antonio Abate and Prof. Dr. Bernd Rech

Perovskite solar cells have been attracting great attentions of solar energy researchers in recent years. Its efficiency development progress is remarkable reaching more than 22% efficiency until now. However, its application in large industrial scale is still questionable because of its instability. Therefore, in the new young investigator group at Helmholtz-Zentrum Berlin: ‘Active materials and interfaces for stable perovskite solar cells’ (INTER-ACTIVE), we focus on the stability of perovskite solar cells by various approaches.

Within the goal of the project’s big picture, I will work on the perovskite layer’s stability as my PhD project. In particular, using different characterisation techniques, I want to understand the dynamic behaviour of electronic components in perovskite solar cells during operational process. Along with this objective, I want to use chemical doping to improve the stability of perovskite.

Carolon Rehermann

Materials synthesis and device optimization for higher bandgap halide perovskites

Supervised by:
Dr. Eva Unger and Prof. Dr. Marcus Bär

Marcel Roß

Development and optimization of vapor deposited perovskite solar cells

Supervised by:
Prof. Dr. Steve Albrecht and Prof. Dr. Bernd Rech

Ibrahim Simsek

Chalcogenide Perovskites

Supervised by:
Dr. Thomas Unold

Johannes Sutter

Antireflective nanostructures in perovskite-silicon tandem solar cells

Member of Helmholtz-Israel International Research School on Hybrid Integrated System for Conversion of Solar Energy (HI-SCORE)

Supervsed by:
Prof. Dr. Bernd Rech and Prof. Dr. Christiane Becker

 

Philipp Tockhorn

Optimierung von Perowskit-Einzelsolarzellen für die Anwendung in hybriden Tandem-Solarzellen

Supervised by:
Prof. Dr. Bernd Rech and Dr. Lars Korte

Christian Wolff

Excitation and charge carrier dynamics in solution and vacuum processed perovskite cells

Supervised by:
Prof. Dr. Dieter Neher and Dr. Thomas Unold

The realization of efficient tandem cells necessitates the combination of subcells with well adapted optical and optoelectronic properties. Even though high efficiencies have now been realized with perovskite-based solar cells, we are far from a detailed understanding of how photovoltaic parameters are related to the chemical structure and the morphology of the active material. Moreover, the picture on the charge carrier dynamics and the electron-photon coupling in these systems is far from being complete.

 The aim of the thesis work is to perform an in-depth experimental investigation of the electron and photon dynamics in perovskite-based solar cells, utilizing state of the art pump-probe techniques. These studies will yield valuable information about the mechanisms which dictate the efficiency of charge carrier generation and extraction. With samples of well-defined composition and structure being supplied by the collaborators, we aim at establishing conclusive structure-property relationships. The outcome of these studies will allow for a knowledge-guided fine-tuning of the photovoltaic properties of these cells.