Electronic structure and localized states in starburst trisphenylquinoxaline

Sigurd K. Schrader; Maria Benedetta Casu; Paolo Imperia; Markus Jandke; Peter Strohriegl

doi:10.1117/12.457472

27 February 2002 Electronic structure and localized states in starburst trisphenylquinoxaline

Sigurd K. Schrader, Maria Benedetta Casu, Paolo Imperia, Markus Jandke, Peter Strohriegl

Proceedings Volume 4464, Organic Light-Emitting Materials and Devices V; (2002) https://doi.org/10.1117/12.457472
Event: International Symposium on Optical Science and Technology, 2001, San Diego, CA, United States

Abstract

Quinoxaline model compounds are interesting materials for Organic Light Emitting Devices (OLEDs) because of their thermal stability and their higher ionization potential in comparison to other electron transporting/hole blocking materials. In this work we studied a starburst trisphenylquinoxaline by means of Ultraviolet Photoelectron Spectroscopy (UPS) and Thermally Stimulated Luminescence (TSL). UPS provided not only the characterization of the valence band structure but also parameters like ionization potential, 6 eV, and, combined with absorption spectroscopy, electron affinity, that are of crucial importance in designing optimized OLED configurations. On the other hand, a wide distribution of localized states occurs in organic layers due to several factors and TSL can investigate these states. The combination of the used techniques together with semi-empirical quantum chemical calculation, gave a detailed description not only of the valence and conduction band of the studied materials, i.e. the energy position of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), but also of the trap distributions localized in the band gap: a shallow one at 0.06 eV and a deeper state centered at 0.24 eV. The full spectroscopic and electrical characterization of the material formed the background for understanding its behavior in heterolayer devices.

Citation Download Citation

Sigurd K. Schrader, Maria Benedetta Casu, Paolo Imperia, Markus Jandke, and Peter Strohriegl "Electronic structure and localized states in starburst trisphenylquinoxaline", Proc. SPIE 4464, Organic Light-Emitting Materials and Devices V, (27 February 2002); https://doi.org/10.1117/12.457472

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