Research

The general theme of my research is based on the analysis of π-conjugated organic compounds as modern electrically conductive materials for application in organic electronics. During my work, I have been conducting research in several areas concerning processes occurring in organic electronic devices. This research has involved comprehensive studies in different scientific areas, across various scientific disciplines. My main expertise is the electrochemical and spectroelectrochemical analysis of organic compounds. Specifically, I’m using electrochemical methods in the studies of doping mechanisms of conjugated compounds to estimate the ionization potential (IP) and electron affinity (EA), which are correlated with HOMO and LUMO energy levels. Additional electrochemical measurements allowed me to investigate the possible side reactions during the degradation of the active layer and the formation of low mobility charge carriers (bipolarons). Coupling electrochemical and spectroelectrochemical methods additionally helped me to accurately and reliably determine features such as the degree of oxidation or reduction of the conjugated compound and degradation potential, which is crucial for assessing the stability of a material upon doping. I also apply visible light and near-infrared spectroscopy coupled with electrochemistry to characterize the fundamentals of the chromatic properties of several conjugated compounds. For this purpose, I use an Electron Paramagnetic Resonance (EPR) spectrometer coupled with a potentiostat. Bearing in mind that in this process two classes of charged quasiparticles take part, one endowed with uncompensated spin (polarons) and the second being diamagnetic (bipolarons), EPR spectroscopy allowed me for direct observation of populations of paramagnetic polarons and to track their changes. I have been also using IR spectroscopy and Raman spectroscopy as the basic tools providing complementary information on the types of chemical bonds present in the chemicals being analyzed.
My current work is mainly devoted to the application of organic compounds as TADF (thermally activated delayed fluorescence) and RTP (room temperature phosphorescence) emitters, from molecular design through to working devices. As the standard practice of my work, I’m designing and screening new materials (in both solution and solid state) for photoluminescence quantum yield (PLQY), fluorescence and phosphorescence emission output, and absorption, in a range of polar and nonpolar solvents, in order to identify the solvatochromism of any CT state. In order to distinguish between different excitation states and the fluorescence and phosphorescence processes, I’m using a gated iCCD camera with a laser excitation system, which allows me to measure emission at different time delays. Using TCSPC (Time-Correlated Single Photon Counting) and iCCD photoluminescence measuring systems, I’m able to obtain the delayed emission (both TADF, TTA – Triplet-Triplet Annihilation and RTP – Room Temperature Phosphorescence) decay time profile and compare the prompt fluorescence and the delayed emission at different temperatures. During my work, I also use impedance spectroscopy for studying relaxation and transport in various electronic devices based on organic materials. All of the gained data in electrochemical and spectroscopic analysis allow me to predict ideal OLED device structures and optimize working parameters. In the final stage of my research, the OLED devices are formed and analysed.

Funding Institutions

I received funding for my research from many sources, from local (Silesian University of Technology), national (Polish National Science Centre, Polish Ministry of Science and Higher Education, Polish Foundation for Science) or international (H2020).

Ongoing Projects

My recent projects cover mainly the designing and analysis of organic compound for Organic Electronics applications like OLED, OPV and OFET, but also electrochromic windows and organic Peltier elements.

2018

FNP - First TEAM - Novel, highly efficient TADF, RTP emitters for organic light emitting diodes

Organic electronics, mainly due to advancements in OLED (Organic Light Emitting Diode) technology, is a fast developing research area having already revolutionized the displays market. This project will demonstrate the use of thermally activated delayed fluorescence (TADF) and Room Temperature Phosphorescence (RTP) emitters in high-efficiency OLEDs, that are stable and do not use scarce and expensive materials such as iridium. The proposed project deals with the comprehensive task of synthesis and analysis of novel ambipolar compounds containing carbazole, phenothiazine, phenoxazine, acridine etc. with different acceptor units based on phenazine, arylene bisimide, diphenylphosphine and dibenzoselenophene Se, Se-dioxides groups, characterization of these compounds and the construction and testing of warm white OLED devices.

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2018

NCN - OPUS - Low turn-on voltage exciplexes based optoelectronic devices. Novel application of Etype delayed fluorescence

The rapid development of molecular electronics effect on lowering the cost of production of optoelectronic circuits like OLED displays. On the other hand, the high demand for thin-film, flexible matrix OLED contributed to the increase in demand for rare and very expensive iridium, which is the main component of typical phosphorescent emitters. In order to eliminated iridium based compounds, scientists began to look for another way to increase the efficient emitters. From a physical point of view, the luminescence process can be divided into two processes fluorescence and phosphorescence, where the first is a rapid process in which the molecule from the singlet excited state returns to the ground state by emitting energy in the form of photons. Phosphorescence is a long lived process associated with moving molecules from singlet excited state to the triplet state. This transition is a quantum forbidden transition and for that the process of Intersystem Crossing (ISC) takes longer. Then, excited triplet state of the molecule relaxes to the ground state. Inside the organic light emitting devices (OLED) after applying potential (charge), electrons and holes in the active substance can be combined to form different excited states, such as the singlet excitonic state and triplet excitonic state. When the charge singlet excitons and triplet, which should theoretically be produced in a ratio of one to three, are formed. In the case of devices based on the fluorescence emission process of fluorescence emission is caused only by the decay of singlet excitons, the state of triplet exciton is prohibited. Quantum yield for singlet excitons is limited to 25%, which means that the triplet excitons is 75%. So far, in the industry one of the ways to improve the process efficiency of light was the use of the phosphorescence process and forming PHOLEDs (Phosphorescence Organic Light-Emitting Diodes). Unfortunately, efficient phosphorescence emitters contain a very expensive iridium and quantum efficiency of real devices is below 15% and the operating voltage above 4 V, which results in a large loss of energy and a shorter lifespan. The innovative idea to increase device efficiency, is to link the process of fluorescence and phosphorescence and to obtain 100% yield by employing the E-type delayed fluorescence (E-DF) also called TADF (Thermally Delayed Fluorescence Activated). In general terms, it means that the molecule from the triplet excited state is going back to the singlet excited state, and then relaxes to the ground state by emitting photons. In this process, excited singlet state and a triplet must have very similar energies. Thanks to that with small amount of energy, molecule is able to move from the triplet excited state back to the singlet excited state, and relax with emission of light. The maximum yield of this process is 100%.
In my project, I will try to use the thermally activated delayed fluorescence (TADF) process for various mixed layers of donor-acceptor (exciplex) as OLED emitter and studied the influence of morphology and thermal properties of layers on emission in order to improve efficiency up to 100% (more than 15% EQE). Such stable systems will help in the future eliminate expensive iridium based compounds in diodes and OLED displays.

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2017

OCTA - Organic Charge Transfer Applications

The overall aim of the project is to create a new international EU-World Network concentrated on organic charge transfer processes and applications. To fulfill this scientific purpose we will form the network from partners which are excellent by themselves in their area of expertise. The network is composed of the Silesian University of Technology (SUT, Poland), University of Durham (UDUR, UK), University of Glasgow (UoG, UK), University of Dusseldorf (UOD, Germany), Universidade Federal de Santa Catarina (UFSC, Brazil), National Taiwan University (NTU, Taiwan) and Osaka University (OU, Japan). To achieve this aim, the four year project will be built upon the existing strong science and innovation base of all partners.

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2015

ORZEL - Boosting the scientific excellence and innovation capacity in organic electronics of the Silesian University of Technology

The overall aim of the project is to boost the scientific excellence and innovation capacity in organic electronics of the Silesian University of Technology (SUT) by creating a network with the high-quality Twinning partners: University of Durham (UDUR), Institute of Nanoscience and Cryogenics, Commissariat à l’Energie Atomique et aux Energies Alternatives (INAC) and Eindhoven University of Technology (TUE). To achieve this aim, the three year project was build upon the existing strong science and innovation base of chosen universities and research institutions.

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2015

EXCILIGHT - Donor-Acceptor Light Emitting EXCIplexes as Materials for Easy-to-Tailor Ultra-efficient OLED LIGHTing

EXCILIGHT is an Innovative Training Network (ITN), funded as part of the Marie Skłodowska-Curie Actions of the European Union's Horizon 2020 Research and Innovation Programme. The project's objective is to train the next generation of bright young scientists by tackling major research projects.

Our network will train 15 Early Stage Researchers (PhD students) in the development and application of exciplex and TADF (Thermally Activated Delayed Fluorescent) emitters, who will be able to apply their expertise directly in future positions. EXCILIGHT is characterised by an innovative multidisciplinary approach, based on

a combination of synthesis, physical characterisation and development of devices with the lighting industry,
an appropriate balance between research and transferable skills training, and
a strong contribution from the private sector, including leading industry and SMEs, through mentoring, courses and secondments.

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Fellowship Available

We have available 2 postdoc positions for people in area of organic synthesis of conjugated compounds, 3 PhD positions and 3 students in area of analysis of organic compounds for organic electronics applications. Contact for more information.