Intense deep blue exciplex electroluminescence from NPB/TPBi:PPh3O-based OLEDs and their intrinsic degradation mechanisms (Conference Presentation)
Chemistry, Physics and Astronomy, Microelectronics Research Center (MRC)
SPIE Organic Photonics + Electronics
Journal or Book Title
Proceedings of SPIE
Organic Light Emitting Materials and Devices XX
August 28, 2016
San Diego, CA
We describe intense and efficient deep blue (430 – 440 nm) exciplex emission from NPB/TPBi:PPh3O OLEDs where the luminous efficiency approaches 4 Cd/A and the maximal brightness exceeds 22,000 Cd/m2. Time resolved PL measurements confirm the exciplex emission from NPB:TPBi, as studied earlier by Monkman and coworkers [Adv. Mater. 25, 1455 (2013)]. However, the inclusion of PPh3O improves the OLED performance significantly. The effect of PPh3O on the EL and PL will be discussed. The NPB/TPBi:PPh3O-based OLEDs were also studied by optically and electrically detected magnetic resonance (ODMR and EDMR, respectively). In particular, the amplitude of the negative (EL- and current-quenching) spin 1/2 resonance, previously attributed to enhanced formation of strongly EL-quenching positive bipolarons, increases as the OLEDs degrade in a dry nitrogen atmosphere. This degradation mechanism is discussed in relation to degradation induced by hot polarons that are energized by exciton annihilation.
Society of Photo-Optical Instrumentation Engineers (SPIE)
Shinar, Joseph; Hippola, Chamika M.; Danilovic, Dusan; Bhattacharjee, Ujjal; Petrich, Jacob W.; and Shinar, Ruth, "Intense deep blue exciplex electroluminescence from NPB/TPBi:PPh3O-based OLEDs and their intrinsic degradation mechanisms (Conference Presentation)" (2016). Chemistry Conference Papers, Posters and Presentations. 16.