Novel host materials for blue phosphorescent OLEDs

Peter Strohriegl; Daniel Wagner; Pamela Schrögel; Sebastian T. Hoffmann; Anna Köhler; Ute Heinemeyer; Ingo Münster

doi:10.1117/12.2023305

27 September 2013 Novel host materials for blue phosphorescent OLEDs

Peter Strohriegl, Daniel Wagner, Pamela Schrögel, Sebastian T. Hoffmann, Anna Köhler, Ute Heinemeyer, Ingo Münster

Proceedings Volume 8829, Organic Light Emitting Materials and Devices XVII; 882906 (2013) https://doi.org/10.1117/12.2023305
Event: SPIE Organic Photonics + Electronics, 2013, San Diego, California, United States

Abstract

We present two classes of host materials for blue phosphors. The first are carbazole substituted biphenyls 1-9. In these CBP-type materials the triplets are confined to one half of the molecules by using either twisted biphenyls or by a metalinkage of the carbazoles to the biphenyl. We obtained high triplet energies of 2.95-2.98 eV and high glass transition temperatures in the range of 100-120 °C. OLEDs were fabricated using the host material 6 and the carbene emitter Ir(dbfmi) with pure blue emission at 450 nm. The devices achieved an external quantum efficiency of 8.7% at 100 cd/m² and 6.1% at 1000 cd/m². MBPTRZ with an electron transporting biscarbazolyltriazine that is separated from the hole transporting carbazole by a non-conjugated, meta-linked biphenyl unit is an example for a bipolar matrix material. The excellent glass forming properties and the high T_g of 132 °C ensure morphological stability in OLEDs. The meta-linkage and the additional twist at the biphenyl unit, which is achieved by two methyl groups in the 2- and 2’-position of the biphenyl in MBPTRZ leads to a decoupling of the electron accepting and electron donating part and therefore to a high triplet energy of 2.81 eV. DFT calculations show a clear separation of the electron and hole transporting moieties. A phosphorescent OLED with MBPTRZ as host and FIrpic as emitter reached a maximum external quantum efficiency of 7.0%, a current efficiency of 16.3 cd/A and a power efficiency of 6.3 lm/W.

Citation Download Citation

Peter Strohriegl, Daniel Wagner, Pamela Schrögel, Sebastian T. Hoffmann, Anna Köhler, Ute Heinemeyer, and Ingo Münster "Novel host materials for blue phosphorescent OLEDs", Proc. SPIE 8829, Organic Light Emitting Materials and Devices XVII, 882906 (27 September 2013); https://doi.org/10.1117/12.2023305

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available