Inorganic and Organic SolStore

Doctoral position for the development of organic devices for photovoltaic energy conversion and storage devices

The combination of photovoltaic energy conversion and charge storage enhances the use of light energy harvesting tremendously and can be achieved at different integration levels. An existing route is the modular combination of separated solar cells and batteries (level I). The next level would be a monolithic device in which the battery and the solar cell are still separated by a metallic electrode (level II). The highest integration (level III) merges both functions (conversion and storage) into one device using multifunctional materials.

This project of livMatS focuses on the development of organic devices of level II and III (SolStore). For the development of such SolStore devices, the following questions have to be solved:

• What is the ideal device architecture?
• How should the individual SolStore devices be interconnected and integrated to achieve an efficient and robust device with optimal electrical output parameters?
• What absorber and battery materials are ideally suited? • Which impact do interfaces between the absorber and charge transport layers have?
• What type of process technologies such as e.g. spin-coating, blade-coating, evaporation, plasma-enhanced vapor deposition, sputtering and printing should be used for the fabrication of the different components of the device?
• Which characterization and simulation methods are suited to analyze device performance and loss mechanisms?

These questions will be addressed in a multidisciplinary team of scientists working on the modeling of materials properties, synthesis and characterization of new materials as well as device design, fabrication and simulation. The fabrication of devices will be developed in cooperation with the Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg.

The doctoral candidate will be part of this team and mostly focus on the fabrication and analysis of organic combined conversion and storage devices of level II and III. Applicants should have a master degree in electrical engineering , physics, material science (or something similar) as well as strong experience in electrical device fabrication and characterization. Experience in semiconductor physics, process technology and/or electrochemistry, for example in the field of batteries, is required. Furthermore, eagerness to acquire further knowledge and to work in an interdisciplinary international team are mandatory as well as good self-organization and the ability to work independently, although under supervision. We expect fluency in English.

Applications are closed as of 30^th June 2019. We expect to fill this position by October 1^st 2019. The position will be supervised by Dr. Uli Würfel and Prof. Dr. Birgit Esser.

Doctoral position for the development of photoelectrodes for organic photo-charging batteries

The development of highly integrated photo-charging devices is a growing research topic. While one can couple a solar cell with a battery in a modular fashion, new research directions tackle the development of integrated materials systems where light-induced charge generation and storage take place in one material.

• What type of materials can combine both light harvesting and charge storage?
• What type of different charge-storing mechanisms can come into play?
• How can the photo-electrochemical properties of such materials / materials systems be characterized best?
• What is the best way to assemble a photo-charging battery?

• How should a photo-charging battery device be designed and optimized?

These questions will be addressed in a multidisciplinary team of scientists working on modeling of materials properties, synthesis and characterization of new materials as well as device design, fabrication and simulation.

The doctoral candidate will be part of this team and mostly focus on the synthesis and characterization of organic (thin film) photoelectrodes and investigate their aptitude for light-induced charge storing by applying several (photo)electrochemical techniques.

Applicants should have a master's degree in chemistry with a specialization in synthetic Organic Chemistry. Experience in electrochemistry, for example in the field of solar cells or batteries, is required. Furthermore, eagerness to acquire further knowledge and to work in an interdisciplinary international team are mandatory as well as good self-organization and the ability to work independently, although under supervision. We expect fluency in English.

Applications are closed as of 30^th June 2019. We expect to fill this position by 1^st October 2019. The position will be supervised by Prof. Dr. Birgit Esser, Prof. Dr. Anna Fischer and Dr. Uli Würfel.

Doctoral position for the development of inorganic devices for photovoltaic energy conversion and storage devices

The combination of photovoltaic energy conversion and charge storage enhances the use of light energy harvesting tremendously and can be achieved at different integration levels. An existing route is the modular combination of separated solar cells and batteries (level I). The next level would be a monolithic device in which the battery and the solar cell are still separated by a metallic electrode (level II). The highest integration (level III) merges both functions (conversion and storage) into one device using multifunctional materials. This project of livMatS focuses on the development of inorganic devices of level II and III (SolStore).

• What is the ideal device architecture?
• How should the individual SolStore devices be interconnected and integrated to achieve an efficient and robust device with optimal electrical output parameters?
• What absorber and battery materials are ideally suited?
• What is the function of interfaces between charge transport layers?

• What type of process technologies such as evaporation, plasma-enhanced vapor deposition, sputtering, blade coating and printing should be used for the fabrication of the different components of the device?

• Which characterization and simulation methods are suited to analyze device performance and loss mechanisms?

These questions will be addressed in a multidisciplinary team of scientists working on modeling of materials properties, synthesis and characterization of new materials as well as device design, fabrication and simulation. The fabrication of devices will be developed in cooperation with the Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg.

The doctoral candidate will be part of this team and mostly focus on the fabrication and analysis of inorganic combined conversion and storage devices of level II and III.

Applicants should have a master degree in electrical engineering or physics as well as strong experience in electrical device fabrication and characterization. Experience in semiconductor physics, process technology and/or electrochemistry, for example in the field of batteries, is required. Furthermore, eagerness to acquire further knowledge and to work in an interdisciplinary international team are mandatory as well as good self-organization and the ability to work independently, although under supervision. We expect fluency in English.

Applications are closed as of 19^th June 2019. We expect to fill this position by 1^st July 2019. The position will be supervised by Prof. Dr. Stefan Glunz and Prof. Dr. Anna Fischer.

Doctoral position for the development of photoelectrodes for inorganic photo-charging batteries

The development of highly integrated photo-charging devices is a growing research topic. While one can couple a solar cell with a battery in a modular fashion, new research directions tackle the development of integrated materials systems where light-induced charge generation and storage take place in one material.

• What type of materials can combine both light harvesting and charge storage?
• What type of different charge-storing mechanisms can come into play?
• How can the photo-electrochemical properties of such materials / materials systems be characterized best?
• What is the best way to assemble a photo-charging battery?

• How should a photo-charging battery device be designed and optimized?

These questions will be addressed in a multidisciplinary team of scientists working on modeling of materials properties, synthesis and characterization of new materials as well as device design, fabrication and simulation.

The doctoral candidate will be part of this team and mostly focus on the synthesis and characterization of inorganic (thin film) photoelectrodes and investigate their aptitude for light-induced charge storing by applying several (photo)electrochemical techniques.

Applicants should have a master's degree in chemistry or material science as well as strong experience in material synthesis and characterization. Experience in electrochemistry, for example in the field of batteries, supercapacitors or (photo)electrochemistry, is required. Furthermore, eagerness to acquire further knowledge and to work in an interdisciplinary international team are mandatory as well as good self-organization and the ability to work independently, although under supervision. We expect fluency in English.

Applications are closed as of 1^st May 2019. We expect to fill this position by 1^st July 2019 at the latest. The position will be supervised by Prof. Dr. Anna Fischer, and Prof. Dr. Stefan Glunz.

Doctoral position in the area of halogeno-perovskites for an inorganic photo-charging battery

Hybride organic-inorganic perovskites (for example MAPbI₃) are excellent dies for the solar cell. In the framework of livMatS, perovskites materials should be developed for the application in a photo-charged battery. First, the focus is on the synthesis of HOIPS for the use in a surrounding of a photo-charged battery. At the final stage the HOIPs should serve as a battery material by itself. While many HOIPs are described for the use in PV cells, there is nearly no knowledge, how the process of charge separation generated by the absorption of light can be integrated into a storage process. Therefore known and new materials will be synthesized and tested with respect to this use. Besides thermal and chemical stability the photochemical and electrochemical properties are of high interest. A special challenge is the interaction with the other materials of the device. Central task is the synthesis of new materials and the charactrasation by XRD and other spectroscopic methods.

Applicants should have a M.Sc. in chemistry, materials science or related disciplines. Knowledge of synthesis and characterization of perovskite materials is required and experience in the set-up of devices for PV is a plus but not mandatory. Willingness to integrate into the SolStore group and to work closely with other members of related projects is mandatory.

Applications are closed as of 1^st June 2019. We expect to fill this position by 1^st October 2019. The position will be supervised by Prof. Dr. Harald Hillebrecht and Prof. Dr. Anna Fischer.

Doctoral position in theoretical solid-state physics of inorganic photo-charging batteries

Inorganic SolStore intends to combine a perovskite solar-cell material (PSC) with a lithium-ion battery material (LIB) to an integrated all-solid-state thin-film-heterostructure energy-storage system.

This project will focus on the theoretical solid-state physics of the photo-electronic and electro-chemical properties of prototypical inorganic perovskite-type compounds ABX₃ or A₂BX₄ (A: monovalent cations, e.g. Cs; B: divalent cations, e.g. Pb; X: monovalent anions, e.g. Br) for the light-absorbing and/or cation-storing crystalline layers in heterostructure systems).

The scientific issues to be studied by the doctoral candidate in this project are:

• Up to which concentrations can light alkali-metal cations like Li ions be incorporated interstitially into the perovskite-type compounds?
• What are the thermodynamical limits for structural stability of the perovskites?
• What are the electro-chemical ranges for inserting /extracting the cations into/out of the perovskites?
• How are the photo-electronic properties of the perovskites affected by the incorporated cations and heterophase interfaces?

The photo-electronic properties of the perovskites, namely electronic band structures, defect levels in band gaps originating from compositional variations, structural defects, or heterophase interfaces, and other solid-state properties of electrons or holes in semiconductors, will be investigated by means of first-principles electronic-structure calculations based on density functional theory (DFT). The thermodynamics of perovskite compound stability (in terms of formation energies) and the kinetics of insertion/extraction of cations (in terms of activation energies) as function of the concentration of alkali-metal cations, will be studied by means of DFT calculations combined with atomistic modelling (molecular statics/dynamics simulations) based on empirical interatomic forces (bond-valence or rigid-ion potentials).

As an applicant, you should have an academic MSc degree with excellent grades in physics or chemistry which entitles you to admission to a PhD programme at the University of Freiburg. You are trained in solid-state physics or inorganic chemistry and skilled in doing scientific research, strongly interested in and committed to solid-state theory and computational materials modelling, and highly motivated to work with an interdisciplinary team of theorists and experimentalists. Further information with regard to the application procedure will be provided . We intend to fill this position by mid of 2019. Supervisor of this PhD project is Prof. Dr. Christian Elsässer.

Applications are closed as of March 15^th 2019. We expect to fill this position by April 1st 2019.The position will be supervised Prof. Dr. Christian Elsässer, Prof. Dr. Harald Hillebrecht and Prof. Dr. Ingo Krossing.

Doctoral postion in the area of charge transfer at interfaces

Charge transfer over complex interfaces is of high importance in the research area of the project Inorganic and Organic SolStore, where solar energy conversion and storage will be combined within the same material. Here, junctions between organic and inorganic/metallic and semi-metallic regions will determine the overall device performance. Their structural, electronic and optical properties will be investigated with density-functional theory. Tuning of molecular properties e. g. through optimized Fermi level alignment will reveal the optimal choice of the organic phases and in this way guide their synthesis. The effect of different anchor groups and substituents will be screened. Predicted optical- and electrochemical properties will be contrasted with the experimental observations of WPO1 to obtain insights into the origins of the spectral features observed.

Charge transfer at interfaces is also a central topic in the project Interfaces, charge-transfer and non-adiabatic processes and their exploitation in a frequency-tunable tribogenerator. We will employ electronic structure calculations to investigate the relevant interfacial transport properties. The main topic will be the elucidation of the working principles of tribogenerators, where the calculations shall unravel the electrification of the contacting interfaces. Different hypotheses for the origins of charge separation will be explored within electronic structure calculations in the ground-state of the material as well as in excited state investigations.

Applicants should have a M.Sc. in physics, chemistry, materials science or related disciplines. Knowledge of a scientific programming language (e.g. Python) is required and experience with high performance computing is a plus but not mandatory. Willingness to integrate into larger software development projects and to work closely with experimentalists is mandatory

Applications are closed as of March 11^th 2019. We expect to fill this position by April 2019. The position will be supervised by Prof. Dr. Michael Moseler and PD Dr. Michael Walter.

Postdoctoral position for the development of photoelectrodes for inorganic and organic photo-charging batteries

The development of highly integrated photo-charging devices is a growing research topic. While one can couple a solar cell with a battery in a modular fashion, new research directions tackle the development of integrated materials systems where light-induced charge generation and storage take place in one material.

• What type of materials can combine both light harvesting and charge storage?
• What type of different charge-storing mechanisms can come into play?
• How can the photo-electrochemical properties of such materials / materials systems be characterized best?
• What is the best way to assemble a photo-charging battery?

• How should a photo-charging battery device be designed and optimized?

These questions will be addressed in a multidisciplinary team of scientists working on modeling of materials properties, synthesis and characterization of new materials as well as device design, fabrication and simulation.

The postdoctoral candidate will be part of this team and focus on the synthesis and characterization of nanostructured/porous inorganic and organic thin film photo-electrodes and investigate their aptitude for light-induced charge storing by using several (photo)electrochemical techniques.

Applicants should have a PhD in chemistry or material science and a strong publication track-record. Expertise in thin film synthesis and characterization, photovoltaic materials and/or battery materials and (photo)electrochemistry is required. Furthermore, eagerness to work in an interdisciplinary and international team is mandatory as well as good self-organization and the ability to work independently. We expect fluency in English.

Applications are closed as of February 25^th 2019. We expect to fill this position by 1^st April 2019. The position will be supervised by Prof. Dr. Anna Fischer, Prof. Dr. Birgit Esser and Dr. Uli Würfel.

Further positions in the SolStore project will be posted shortly.