Our recent paper together with our colleagues at the Leibniz Institute of Polymer Research Dresden (IPF), is featured in Advanced Science News. This work discusses a novel way to achieve thermally activated delayed fluorescence in polymers through an extension of the HOMO conjugation, which ultimately leads to a smaller splitting between singlet and triplet excited charge transfer states. The paper can be found here: Conjugation-Induced Thermally Activated Delayed Fluorescence (TADF): From Conventional Non-TADF Units to TADF-Active Polymers.
The DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM) will take place from March 19 – 24 in Dresden this year. Below, you find a list of our group’s contributions throughout the week. We are looking forward to an exciting and fruitful week of discussions and exchange. See you there. (There is even a hashtag for the event: #DPGDD17)
|Mo, 11:00||CPP 7.1||Two-color warm white hybrid OLEDs from thermally activated delayed fluorescence — Ludwig Popp, Paul Kleine, Reinhard Scholz, Ramunas Lygaitis, Olaf Zeika, Axel Fischer, Simone Lenk, and Sebastian Reineke|
|Mo, 11:15||CPP 7.2||Conjugation induced thermally activated delayed fluorescence — Paul Kleine, Qiang Wei, Yevhen Karpov, Xianping Qiu, Hartmut Komber, Karin Sahre, Anton Kiriy, Ramunas Lygaitis, Simone Lenk, Brigitte Voit, and Sebastian Reineke|
|Mo, 12:15||CPP 7.6||Ultrathin metal electrode for bottom-emitting OLEDs on buckled substrates — Yungui Li, Toni Bärschneider, Paul-Anton Will, Yuan Liu, Simone Lenk, and Sebastian Reineke|
|Di, 15:45||CPP 26.8||Absolute optical sensor based on biluminescence — Caterin Salas Redondo and Sebastian Reineke|
|Mi, 18:30||CPP 50.13||controlling excitons in exciplex host systems for efficient white OLEDs — Yuan Liu, Simone Lenk, Karl Leo, and Sebastian Reineke|
|Mi, 18:30||CPP 50.19||Synthesis and characterisation of the new emitters for OLED applications — Ramunas Lygaitis, Olaf Zeika, Reinhard Scholz, Ludwig Popp, Paul Kleine, Simone Lenk, and Sebastian Reineke|
|Mi, 13:00||DS 29.14||Influence of radiative efficiency and dipole orientation on optimal layer thicknesses of monochrome OLEDs for maximum EQE — Paul-Anton Will, Cornelius Fuchs, Reinhard Scholz, Simone Lenk, and Sebastian Reineke|
|Mi, 15:15||DS 34.2||Determination of the molecular orientation in absorptive organic thin films — Christian Hänisch, Simone Lenk, and Sebastian Reineke|
|Mi, 09:30||HL 52.1||Full Range Electrothermal Modeling of Organic Light-emitting Diodes — Axel Fischer, Koen Vandewal, Simone Lenk, and Sebastian Reineke|
|Mi, 15:00||HL 64.19||Diffuse Transmission and Reflection of Light Scattering Polymer Substrates for Organic Light-emitting Diodes — Pen Yiao Ang, Georg Marks, Abdalla Mahmoud, Axel Fischer, Simone Lenk, and Sebastian Reineke|
Ryutaro Komatsu (see below) is currently visiting our group as part of an ongoing exchange program between TU Dresden and Universities from Japan. He is a PhD candidate of Prof. Junji Kido from Yamagata University – good chance to see some of their recent work.
|Mi, 18:30||CPP 50.14||Efficient Deep-blue Pyridimidine-based TADF Emitters Using a Highly Twisted Molecular Skeleton — •Ryutaro Komatsu, Tatsuya Ohsawa, Hisahiro Sasabe, Kohei Nakao, Yuya Hayasaka, and Junji Kido|
This year, the 14th European Conference on Molecular Electronics (ECME) will be
held in Dresden on August 29 – September 2, 2017. Important date to remember and of course consider is the deadline for the Call for Papers, which is March 31, 2017. Please check it out to learn more about the different topics the conference will cover. The event already has a broad and exciting collection of invited speakers and now it is looking for your contribution to turn it into a great and vivid week of molecular electronics science.
In a recent collaboration with our colleagues at the Leibniz Institute of Polymer Research Dresden (IPF), we have developed polymers that show thermally activated delayed fluorescence (TADF) properties with high efficiency. This work has now been published in Advanced Functional Materials under the title: Conjugation-Induced Thermally Activated Delayed Fluorescence (TADF): From Conventional Non-TADF Units to TADF-Active Polymers. Interestingly, the monomer building block does not show TADF but rather only phosphorescence. Hence, the TADF property is induced as a consequence of increased conjugation during polymer formation. Ultimately, the singlet-triplet splitting is reduced in the polymer to allow for TADF. The emitter shows sky-blue emission with roughly 70% PLQY. This report includes the synthesis of the monomer and polymer materials, quantum chemical calculations and a detailed photo-physical characterization.
In this paper entitled ‘Transparent and color-tunable organic light-emitting diodes with highly balanced emission to both sides‘ we demonstrate transparent, two-color, stacked OLEDs that allow for balanced top- and bottom-emission. Making use of ultra thin, composite metal electrodes, this design avoids the use of ITO, such that this architecture can be transferred to flexible substrates. Careful optical design made it possible that the luminance of the device is virtually identical to both viewing directions, which is a great improvement over many earlier device layouts.
Ramon Springer joined the group of Prof. Jang Hyuk Kwon (Department of Information Display, Kyung Hee University, South Korea) to carry out a Master thesis topic within the international Masters course Organic and Molecular Electronics (OME) at the TU Dresden. His thesis task was to develop a white-light emitting, multiple OLED stack based on blue and yellow units to be used in AMOLED displays. Here, aside from the optimization of device efficiency, the color quality and angular stability were parameters to be optimized. His work led to a recent publication in Optics Express entitled “Cool white light-emitting three stack OLED structures for AMOLED display applications“. Congratulations to a very successful research stay abroad.
Our new paper entitled “Adjustable white-light emission from a photo-structured micro-OLED array” published in Light: Science & Applications discusses an approach towards micro-OLED arrays made of differently emitting sub pixels without non-emissive areas. This is achieved using orthogonal lithography techniques in a way that only the first OLED unit is structured while the next one to follow is made in a “fill-the-gap” approach. In this conceptual demonstration, we pair blue and yellow OLEDs in a stripe layout, which can be addressed individually for complete color tunability. Feature sizes of the stripes are down to 20 micrometer.