Functional Materials (FM)

Synthesis and Nanostructuring of Heteroazulene-Materials for Thermoelectric Generators

Maria Garcia Hernandez — Thu, 30 Aug 2018 11:54:09 +0000

Synthesis and Nanostructuring of Heteroazulene-Materials for Thermoelectric Generators Maria Garcia H… Thu, 08/30/2018 - 13:54

The cooperation between the Lemmer group (KIT) and the Bunz group (Heidelberg University, Uni HD) about new materials for thermoelectric generators (TEG) is a multidisciplinary project at the interface of organic chemistry, physical chemistry and material science. Thermoelectric generators are devices for the conversion of (waste) heat to electrical power and are key components for energy recycling. Organic thermoelectric materials offer the advantage of flexibility and large area printing of the active materials, which makes them adjustable to different heat sources and more cost effective through high throughput techniques.

During the last project phase a new thiaazulenic building block was created by our synthetic team (Uni HD), polymerized in collaboration and with the know-how of the material team (KIT) and finally tested in thermoelectric generators (KIT).

We could outperform the standard literature material (PEDOT:Tos) in terms of the Seebeck coefficient (88.6 μV/K vs ca. 50.0 μV/K) and are now looking in to different doping possibilities and fine tuning of the molecular structure.

Research bridges

Functional Materials (FM)

Start date

01/01/2018

12/31/2018

Project management

Institute of Organic Chemistry

Heidelberg University

Research Group Bunz

Director Research Bridge FM

Executive Director

Light Technology Institute

Karlsruhe Institute of Technology

Research Group Uli Lemmer

Nanoparticles in Porous organic coordination compounds: from functional molecules to functional materials

Maria Garcia Hernandez — Thu, 30 Aug 2018 11:56:35 +0000

Nanoparticles in Porous organic coordination compounds: from functional molecules to functional materials Maria Garcia H… Thu, 08/30/2018 - 13:56

Das Projekt hatte zum Ziel, formstabile organische Käfigverbindungen zu synthetisieren und diese zum einen mittels Lage-bei-Lage-Abscheidung auf Oberflächen aufwachsen zu lassen, wobei diese sich entlang einer kristallinen Vorzugsrichtung orientieren sollten. Dieses ist nach mehreren Versuchen für eine [4+6] Iminkäfigverbindung auch gelungen. Hierzu war es nötig, Gold vorher mit Mercaptododekansäure zu beschichten, um den Kristallwachstum zu ermöglichen. Weitere Untersuchungen hierzu stehen noch aus. Im zweiten Teil des Projektes ging es um die Synthese löslicher Käfigverbindungen, die eine Vielzahl an polaren funktionellen Gruppen im Inneren aufweisen, um die Kavität als bevorzugten Raum für die Bildung von Metall- und Metalloxoclustern bereitzustellen. Nach eigehender Entwicklung konnte eine Synthesestrategie entwickelt werden, die einen solchen löslichen Käfig ermöglicht. Folgereaktionen zur Generierung von Metall- und Metalloxoclustern stehen noch an.

Research bridges

Functional Materials (FM)

Start date

01/01/2018

12/31/2018

Project management

Director Research Bridge FM

Deputy Executive Director

Institute of Organic Chemistry

Heidelberg University

Michael Mastalerz

Institute of Functional Interfaces

Karlsruhe Institute of Technology

Until September 2018

Towards High Yield PERovskite solar cells by inkjet printing

Regine Kleber — Mon, 12 Nov 2018 16:08:24 +0000

Towards High Yield PERovskite solar cells by inkjet printing <HYPER> Regine Kleber Mon, 11/12/2018 - 17:08

Perovskite solar cells have revolutionised the field of emerging photovoltaic technologies by demonstrating power conversion efficiencies surpassing 22% in just a few years. One of the key issues hindering further progress in the field and the incorporation of these devices into industrial applications is the notorious lack of reproducibility of perovskite devices experienced by researchers worldwide. This issue has resulted in the routine practice of reporting photovoltaic parameter histograms showing wide spread of performance for identically fabricated devices. Recently, we have identified this lack of reproducibility to be linked to large-scale compositional and electronic inhomogeneities of spin-coated perovskite active layers. This, and the need for scalability for future fabrication of perovskite solar cells, highlights the need to focus on the development of alternative deposition methods for perovskite solar cells, such as inkjet printing. In this project, we aim to utilize the inkjet printing deposition method for fabrication of high yield and high performance perovskite solar cells. The project <HYPER> is based on the complementary areas of expertise of the Heidelberg and KIT PIs and will combine inkjet printing of perovskite layers, advanced spectroscopic characterisation and device fabrication. Specifically, we will characterise the compositional and electronic homogeneity of the inkjet printed perovskite layers by x-ray and ultraviolet photoemission spectroscopy mapping experiments and fine tune the deposition parameters for optimal layer quality and homogeneity. The optimal layers will be utilized as active layer in perovskite solar cells, which we will show to exhibit superior reproducibility when compared to reference spin-coated layers. Finally, we will apply the results of the project to large area modules that will exemplify the scalability of inkjet printing and bring perovskite solar cells closer to industrial application.

Research bridges

Functional Materials (FM)

Start date

01/01/2019

12/31/2019

Project management

Centre for Advanced Materials (CAM)

Heidelberg University

Research Group Vaynzof

Institute of Microstructure Technology (IMT)

Karlsruhe Institute of Technology

Research Group Paetzold

Functionalized tetraazapentacenes as electron-transport materials for multi-layer OLEDs

Maria Garcia Hernandez — Thu, 07 Mar 2019 12:42:23 +0000

Functionalized tetraazapentacenes as electron-transport materials for multi-layer OLEDs Maria Garcia H… Thu, 03/07/2019 - 13:42

The goal of our HEiKA project was to find electron transport layer (ETL) materials suitable for multi-layer OLEDs according to the orthogonal solvent concept. Therefore, the material needs to be soluble in some solvents and insoluble in others. This is to prevent solvent penetration in a layer below and layer intermixing.

Tetraazapentazenes (TAPs) are electron-poor derivatives compared to the well-studied pentacene. The TAPs shows a lower lying LUMO energy level (ca. -3.5 eV) and are applicable as electron-transport materials (ETM). We adjust optical properties of mono-bromo TAP by chemical functionalization. We received a high amount of new compounds that are now under investigation. With the synthesized materials mass transport measurements are done using an ultraprecise sorption apparatus with a quartz crystal microbalance. The measurements show that it is possible to tune solubility by adding substituents and get ETL materials that fit the orthogonal solvent concept. Also we found a material/solvent combination with a profoundly increased solvent diffusion coefficient.

Research bridges

Functional Materials (FM)

Project management

Institute of Organic Chemistry

University of Heidelberg

Institute of Thermal Process Engineering

KIT

Contact

The Quest for Stable n-Doped Polyelectrolytes

Maria Garcia Hernandez — Thu, 07 Mar 2019 12:49:59 +0000

The Quest for Stable n-Doped Polyelectrolytes Maria Garcia H… Thu, 03/07/2019 - 13:49

KIT LTI:
In this report, we outline recent advances of thermoelectric n-type polymers that are suitable for printed thermoelectric generators (TEGs). In a first approach, the BiEDOT analogue BiEDOT-Cl was used to synthesize PEDOT-Cl by means of an oxidative polymerization process in the presence of FeTos3. The as-synthesized polymer exhibits a negative Seebeck coefficient and therefore shows n-type behavior. In addition, this polymer shows rheological properties suitable for printing. This paves the way for the integration in printed thermoelectric devices, which enables a dramatic boost of the expected power output in combination with a p-type polymer.

OCI HD:
In this report, we present new routes and synthetic strategies towards the development of an n-type material, which meet the requirements for application in TEGs. Thereby we focused on heteroazulenes and we able to synthesize two new monomers CETO and F2-CETO as well as polymers P1-P4. Their characterization is ongoing regarding stability, doping mechanism and optoelectronic properties.

Research bridges

Functional Materials (FM)

Project management

Institute of Organic Chemistry

Heidelberg University

Research Group Bunz

Director Research Bridge FM

Executive Director

Light Technology Institute

Karlsruhe Institute of Technology

Research Group Uli Lemmer

Silicon polyoxolenes: open-shell building blocks for the construction of magnetic or conductive covalent organic frameworks.

Maria Garcia Hernandez — Tue, 10 Dec 2019 14:38:38 +0000

Silicon polyoxolenes: open-shell building blocks for the construction of magnetic or conductive covalent organic frameworks. Maria Garcia H… Tue, 12/10/2019 - 15:38

Microporous frameworks composed of organic linkers and metal atom nodes (MOFs) or fully covalent networks (COFs) are considered as functional materials of the future. However, to fulfill such promises, they must be equipped with function. The field of conductive or magnetic frameworks is an especially intriguing and highly active research area. Whereas conductivity and magnetism within MOFs have already been tackled by the application of redox-active linkers, analogue strategies in COFs are unexplored – due to the lack of building blocks. Silicon-catecholate based covalent organic frameworks at one side and silicon-catecholate based redox-active complexes on the other, emerged only recently, quasi simultaneously. The same road that was leading to electroactive MOFs can now be explored with SiCOFs. This work aims to study silicon polyoxolenes as suitable open-shell building blocks for the construction of magnetic or conductive SiCOFs, enabling their synthesis by reticular design. A systematic “bottom-up” approach will disclose the magnetic properties within the monomeric building-blocks first, followed by the subsequent investigation of the di- and trimeric diradicals connected through conjugated polytopic linkers. At the same time, an ad hoc synthesis of extended networks, starting from commercial precursors, will be followed. The collaboration between the Greb group (molecular silicon chemistry) and the Powell group (magnetism and MOFs) ideally merges their strengths within both fields of research. The understanding of electron-exchange within metal-free silicon polyoxolenes is not only very satisfying from a fundamental perspective, but such COFs would as well stand for a major step toward an ecologically and economically benign alternative for this future type of functional materials – based on the most abundant elements in the earth crust.

Research bridges

Functional Materials (FM)

Start date

01/01/2020

12/31/2020

Project management

Anorganisch-Chemisches Institut

Universität Heidelberg

Lutz Greb

Institut für Anorganische Chemie

Karlsruher Institut für Technologie

Annie Powell

On-Chip Fabrication of 3D Bio-Polymer µ-Arrays for Correlative “Cell Clinic”

Maria Garcia Hernandez — Thu, 10 Dec 2020 14:10:21 +0000

On-Chip Fabrication of 3D Bio-Polymer µ-Arrays for Correlative “Cell Clinic” Maria Garcia H… Thu, 12/10/2020 - 15:10

It is well established that human pluripotent stem cells undergo apoptosis unless making colonies. Tanaka et al. recently reported that the adhesiveness of human induced pluripotent stem (hiPS) cells to the surrounding environment critically regulates their functions, but the screening of adhesiveness for the control of lineage-specific differentiation is still challenging. The overarching goal of the HEiKA project is to establish a high throughput microfluidic platform CELL CLINIC for human induced pluripotent stem (hiPS) cells by uniting the expertise of a microsystem engineer (Badilita, KIT) and a biophysicist (Tanaka, HD).

Tailor made bio-polymer µ-arrays on a chip:

The uniqueness of our approach is the ability to fabricate µ-arrays of 3D bio-polymer with tunable adhesiveness by electrodeposition of chitosan derivatives on individually accessible µ-electrodes integrated in a microfluidic device developed by Badilita et al. [Badilita2019a]. Badilita et al. also recently reported synthesis of carbon composites from electrodeposited chitosan precursor for various sensing applications [Badilita2020a].

Correlative analytical platform:

In this project we will take the following three approaches:

quantification of cell adhesion strength by morphometric analysis and atomic force microscopy (Tanaka),
electrochemical monitoring of colony forming capability by cyclic voltammetry and impedance spectroscopy (Tanaka), and
assessment of metabolic functions using µ-NMR [Badilita2019] (Badilita).

As Tanaka also has a track record in X-ray imaging [Tanaka2020a], we plan to apply for a DFG project to integrate our CELL CLINIC into KORREL Lab (IMT/KIT) for correlative NMR & X-ray measurements.

Research bridges

Advanced Imaging Platform (AIP)

Functional Materials (FM)

Synthetic Biology (SB)

Start date

01/01/2021

12/31/2021

Project management

Institute for Physical Chemistry

University of Heidelberg

Motomu Tanaka

Institute of Microstructure Technology

Karlsruhe Institute of Technology

Vlad Badilita

Benzoin Condensation: Reviving an Old Reaction for New Anode Materials in Organic Batteries

Maria Garcia Hernandez — Thu, 10 Dec 2020 14:15:52 +0000

Benzoin Condensation: Reviving an Old Reaction for New Anode Materials in Organic Batteries Maria Garcia H… Thu, 12/10/2020 - 15:15

Taking into account their manifold benefits, organic batteries are forecast to replace the currently established lithium-ion technology based on inorganic materials in near future. To meet the expectations associated with this technology, various parameters can be fine-tuned by device engineering, though ultimately, the most integral component is represented by the active materials used. At the bottom line, an ideal organic material would be a highly redox stable, comprises a maximum number of functional units per mass, and can be prepared via cost effective and environmentally benign methods. Our vision is that carbonyl-containing molecules and polymers prepared via Benzoin condensation can deliver such next generation anode materials. On the way to this ultimate target, the most important challenges will be addressed in this proof-of-principle study. Beyond this background, the Schaub group (functional molecular materials) and the Scheiba group (carbon-based materials for electrochemical energy storage) join forces to systematically explore this new avenue. Specifically, starting from readily available polyaldehyde precursors, an efficient access to redox active 1,2-diketone containing macrocycles and polymers will be disclosed and the ad hoc prepared materials tested as anodes in organic batteries. With this approach we not only strive to revive an old, yet conceptually simple and appealing class of redox active materials, but also develop an economically efficient and environmentally benign synthetic route for their preparation.

Research bridges

Functional Materials (FM)

Start date

01/01/2021

12/31/2021

Project management

Institute for Organic Chemistry

University of Heidelberg

Tobias Schaub

Institute for Applied Materials

Karlsruhe Institute of Technology

Frieder Scheiba

Fundamental mechanisms of degradation in organic semiconductors and their effect on the performance of organic photovoltaic devices

Maria Garcia Hernandez — Thu, 19 Aug 2021 14:26:14 +0000

Fundamental mechanisms of degradation in organic semiconductors and their effect on the performance of organic photovoltaic devices Maria Garcia H… Thu, 08/19/2021 - 16:26

For the societal relevance of organic electronic technologies, the performance of devices across their entire lifetime is more important than short-lived record-breaking figures-of-merit. This study focused on establishing the fundamental mechanisms that limit the energy payback of a benchmark organic solar cell technology. To this end, we have established in the last year a home-built solar cell degradation testing apparatus with gas-mixing board. This allows cells to be exposed to oxygen, water vapor, and light, and controlled combinations of the above while the figures-of-merit are monitored. After this controlled degradation, we built up setups to study its fundamental causes by tracking the exciton and charge dynamics with transient absorption spectroscopy and the weak sub-bandgap absorption with photo-thermal deflection spectroscopy.

Research bridges

Functional Materials (FM)

Start date

01/01/2015

12/31/2015

Project management

Centre for Advanced Materials (CAM)

Heidelberg University

Research Group Vaynzof

Institute of Microstructure Technology

Karlsruhe Institute of Technology

Nanoporöse halbleitende Oberflächen als neuartige Sensoren (nanOFETs)

Maria Garcia Hernandez — Thu, 19 Aug 2021 14:28:01 +0000

Nanoporöse halbleitende Oberflächen als neuartige Sensoren (nanOFETs) Maria Garcia H… Thu, 08/19/2021 - 16:28

Rigide organische Moleküle mit intrinsischer Mikroporösität wurden als Grundlage für eine völlig neue Art von Sensoranwendungen untersucht. Dazu wurden rigide organische Strukturen synthetisch erzeugt, die sich aufgrund ihres sterischen Verhaltens in Selbstorganisation so anordnen, dass sie ein mikroporöses dreidimensionales Netzwerk ausbilden können. Es wurde anschließend eine Methode entwickelt poröse, polykristalline Dünnfilme aus diesen Molekülen herzustellen. Die Mikroporosität bietet nun die Möglichkeit von außen gezielt verschiedene Stoffe und Stoffsysteme einzubringen, die dann mit den π-Systemen im dreidimensionalen Netzwerk wechselwirken und so die Transporteigenschaften verändern. Die Idee ist, dass sich aus der Leitfähigkeitsveränderung das eingebrachte Stoffsystem oder die Konzentration des eingebrachten Stoffsystems ableiten lässt. Dies wurde zunächst mit verschiedenen Fullerenen als Analyt, sowie in Abhängigkeit von Umgebungsparametern wie Luftfeuchtigkeit und Temperatur untersucht.

Research bridges

Functional Materials (FM)

Start date

01/01/2015

12/31/2015

Project management

Director Research Bridge FM

Deputy Executive Director

Institute of Organic Chemistry

Heidelberg University

Michael Mastalerz

Lichttechnisches Institut (LTI)

Karlsruhe Institute of Technology