New paper: Ultrastable glass emission layers make OLEDs more efficient and durable

Organic light-emitting diodes made from small molecular weight organic semiconductors are composed of multiple functional layers. These layers are in most cases amorphous assemblies of the molecular building blocks. In our joint paper with our collaborators of the Group of Nanomaterials and Microsystems (GNaM) at the Universitat Autònoma de Barcelona entitled ‘High-performance organic light-emitting diodes comprising ultrastable glass layers‘, we shed some light on the growth of these layers. The work is published in Science Advances. The molecules making up the amorphous layers do not necessarily fall into place perfectly so that over time (but these are very long times beyond the lifespan of an OLED) the molecules wiggle into a more compact assembly. This settling can be accelerated greatly if the molecules on the surface are given some extra energy to migrate. Providing excess thermal energy through an elevated substrate temperature, much more stable morphologies – called ultrastable glasses – are formed. The optimum condition for this growth is around 85% of the materials glass transition temperature. 

In our study we have tested this growth condition for four different phosphorescent emitters in one common device stack and found that both the external quantum efficiencies and device lifetimes significantly increased. The illustration below summarizes our work graphically. 

The full citation is: J. Ràfols-Ribé, P.-A. Will, C. Hänisch, M. González-Silveira, S. Lenk, J. Rodríguez-Viejo, S. Reineke, High-performance organic light-emitting diodes comprising ultrastable glass layers. Sci. Adv. 4, eaar8332 (2018). DOI: 10.1126/sciadv.aar8332.

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SPIE Photonics Europe 2018 – PHEBE partners to present

At this year’s SPIE Photonics Europe 2018 in Strasbourg, France, the new conference Organic Electronics and Photonics: Fundamentals and Devices (Conference 10687) will celebrate its inaugural meeting. My colleague Prof. Koen Vandewal (now at Hasselt University) and I are jointly chairing this conference.

This first conference lasts for three days (24 – 26 April 2018) and aims to concentrate the exciting and diverse research using organic materials for electronic and/or photonic applications. The conference starts on Tuesday with a full day focusing on thermally activated delayed fluorescence (TADF), followed by the Wednesday programme discussing organic photovoltaics and photodetectors as well as other optoelectronic and photonic devices, and concludes on Thursday with morning and afternoon sessions on organic light-emitting diodes.

The PHEBE consortium is well represented at this event with Prof. Andy Monkman (Durham University) giving an invited talk in the TADF Session on Tuesday with the title ‘Ultrafast reverse intersystem crossing and 100% PLQY in the same TADF molecule, really!’ followed by another contribution from the PHEBE consortium about white OLEDs using blue TADF emitters by Ludwig Popp et al. (TU Dresden and Kaunas University of Technology) ‘Warm-white hybrid emission from TADF and phosphorescence and its application in OLEDs’. The conference is co-organized by the PHEBE member Prof. Sebastian Reineke.

Many experts in the field of OLEDs and TADF, including Wolfgang Brütting, Reinder Coehoorn, Vladimir Dyakonov, Franky So, Seunghyup Yoo, Eli Zysman-Coleman, will be presenting their newest results. With Cynora GmbH and Osram OLED GmbH, leading European companies working on OLEDs will be also represented at the conference.

To register for this event, please visit http://spie.org/conferences-and-exhibitions/photonics-europe

SPIE Optics+Photonics / Conference OP212 / Call for Papers

The conference Organic Light Emitting Materials and Devices (OP212) goes into its 22nd round (XXII) this year at the SPIE Optics+Photonics 2018 in San Diego. The abstracts for contributions are due February 7, 2018 – so a couple of weeks to go. Don’t miss out this excellent opportunity to showcase your latest research results. A pdf version of the Call for Papers can be downloaded here: OP18P OP212 Call Flyer.

 

Deadline for SPIE Europe 2018 – TODAY / Conference EPE117 is awaiting your submission

Today is the submission deadline for the upcoming SPIE Photonics Europe 2018 (April 22-26, 2018) in Strasbourg, France. So please go forward and submit your abstract to the new Conference Organic Electronics and Photonics: Fundamentals and Devices (EPE117).

We are inviting everyone working in the field of organic electronics and photonics to consider our Conference and to submit an abstract. We are looking forward to a broad, state-of-the-art exchange of research and development trends.

SPIE Europe 2018 /Only 3 days left for abstact submission

The abstract submission deadline for the upcoming SPIE Photonics Europe 2018 (April 22-26, 2018) in Strasbourg, France, is closing in: October 23, 2017, so only 3 days to go!

My colleague Koen Vandewal and I organize the new Conference Organic Electronics and Photonics: Fundamentals and Devices (EPE117).

We are inviting everyone working in the field of organic electronics and photonics to consider our Conference and to submit an abstract. We are looking forward to a broad, state-of-the-art exchange of research and development trends.

Please do also spread the word, if you know colleagues of yours, who might be interested to go.

SPIE Photonics Europe 2018: Join us at a new Conference EPE117

At the upcoming SPIE Photonics Europe 2018 (April 22-26, 2018) in Strasbourg, France, my colleague Koen Vandewal and I organize a new Conference called Organic Electronics and Photonics: Fundamentals and Devices (EPE117). The Call for Papers reads:

Organic materials are interesting for a myriad of photonic and optoelectronic applications due to their tunability of key electronic and optical properties, their versatility of processing, the softness of the solid films formed, and their potential to allow for non-toxic materials. Currently monochrome organic light-emitting diodes are a commercial product used in displays, while organic photovoltaics and sensors for low cost, bio, artificial skin, or wearable applications have seen rapid development in de latest years. On the basis of this very versatile material platform, it is expected that many more, innovative application concepts will be discovered and developed.

Hereby does fundamental research on organic electronics and photonics form the backbone for the discovery of new applications, especially, when materials’ properties are evaluated free of pre-determined applications. Moreover, basic experimental and theoretical research on charge, energy and spin transfer processes, organic-organic interfaces and their electronic structure, will provide structure-property relations and progress existing applications.

The focus of this conference will be on the following topics:

  • optoelectronic organic devices including light-emitting diodes, solar cells, photodetectors, sensors, transistors and switches
  • organic optical systems: waveguides, energy converters, cavities, light directors
  • organic bioelectronics with focus on optics
  • basic research in organic electronics and photonics: spectroscopy, charge generation, transport and recombination, spin,
  • charge and electron transfer interfaces, theoretical calculations and modelling, structure-property relations.

The deadline for abstract submission is October 23, 2017, so a couple of weeks to go.

We encourage you all to submit an abstract and join us for an exciting and inspiring week of fruitful scientific exchange.

International TADF Symposium in Frankfurt is upcoming

On Thursday, September 7, 2017, the International TADF Symposium (organized by cynora GmbH) will take place in Frankfurt. It will be a packed one-day event with a tight focus on OLEDs based on thermally activated delayed fluorescence (TADF). The event will bring together leading industry and academia to share new results and discuss upcoming developments. You can find all the details about speakers and program on the events webpage. It is definitely a very good opportunity to get in touch with the people working on this exciting material development.