Electronic band structure, OLEDs

This approach requires a detailed characterisation of the materials candidates to act as ET or HT layers in OLEDs. Angle Resolved Ultraviolet Photoelectron Spectroscopy (ARUPS) on ordered films provides not only their experimental electronic band structure but also parameters like ionisation potential (//>) and electron affinity Ea) that are of crucial importance in organising better OLED configurations [2-4]. In this work we investigated an amphiphilic derivative of 2,5-diphenyl-l,3,4-oxadiazole by means of Ultraviolet Photoelectron Spectroscopy (UPS) and ARUPS. This structure is based on a very stable moiety [5, 6] and the family of substituted 2,5-diphenyl-1,3,4-oxadiazole can be used as emitting as well as hole blocking/electron transporting layer in OLEDs [7]. 

The peculiar band structure of CPs is responsible for interesting optical properties including excitation driven visible light emission [or photolu-miniscence (PL)] in solution form. The use of CP for LEDs is inspired by possibility of electric field (E) driven luminiscence [or electroluminiscence (EL)] by the thin and defect free films of suitable CPs. The discovery of OLEDs dates back to 1989 and can be credited to Prof. Sir. Richard F. Friend (who is also known as Father of Organic Electronics ) and coworkers, who invented the first thin-film OLED based on electroluminiscent layer of PPV (only few nanometers thick) via a facile solution processing route... 

---