Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 41: Inorganic/Organic Interfaces

O 41.35: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster B

Tuning Molecular Electronic "Set Screws" to Realize Deep-Blue Triplet Emitters - an STM/STS study — •Pascal Raphael Ewen^1,3, Jan Sanning¹, Nikos Doltsinis², Cristian Alejandro Strassert², and Daniel Wegner³ — ¹Physikalisches Institut & CeNTech, Münster, Germany — ²Institut für Theoretische Physik, Münster, Germany — ³Institute for Molecules and Materials, Nijmegen, The Netherlands

State-of-the-art organic light emitting diodes (OLEDs) are still under intense investigation both in fundamental research and development as challenges, e.g. efficient deep-blue emitters, are still unsolved. Moreover, the physical and electronic behavior on the nanoscale after thermal sublimation at the molecule-substrate interface is often unknown but can drastically determine the device performance. Using low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) we study the adsorption and electronic structure of new types of Pt(II) complexes on Au(111). These molecules exhibit photoluminescent quantum yields up to 65% and are used in prototype devices. By mapping frontier orbitals of systematically varied organometallic complexes we are able to evaluate and control the impact of the ligands on the HOMO-LUMO gap which basically determines the emitted wavelength. Our findings provide a strategy to characterize and tailor organometallic molecules with targeted properties. Furthermore, we show that potential dissociation during the deposition is an important issue.