Elucidating the effects of guest-host energy level alignment on charge transport in phosphorescent OLEDs
Journal Publication ResearchOnline@JCUAbstract
The correct choice of guest and host molecules in the light-emitting layer is essential for developing high performance phosphorescent organic light emitting devices. However, the effects of the energy level alignment between the guest and the host are yet to be fully elucidated. In this Letter, we use kinetic Monte Carlo simulations to investigate guest-host systems in which the energy gap of the guest and host is fixed, and only the relative energies of the ionization potential/electron affinity are changed to elucidate their effect on charge transport. It was determined that the mobility balance in the blend was sensitive to the energy level alignment, allowing balanced active layer mobility to be achieved despite the hole and electron mobilities being different by around one order of magnitude. It was also found that the mobility of the faster carrier was more sensitive to the energy level alignment than that of the slower carrier due to reduced slower carrier thermalization under deep charge trapping on the guest.
Journal
Applied Physics Letters
Publication Name
N/A
Volume
115
ISBN/ISSN
1077-3118
Edition
N/A
Issue
N/A
Pages Count
5
Location
N/A
Publisher
American Institute of Physics
Publisher Url
N/A
Publisher Location
N/A
Publish Date
N/A
Url
N/A
Date
N/A
EISSN
N/A
DOI
10.1063/1.5131680