S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Electrical and Computer Engineering (전기·정보공학부) Others_전기·정보공학부
Improved blue light-emitting polymeric device by the tuning of drift mobility and charge balance
- Chin, Byung Doo; Suh, Min Chul; Lee, Seong Taek; Chung, Ho Kyoon; Lee, Changhee
- Issue Date
- American Institute of Physics
- Appl. Phys. Lett. 84, 1777
- We have prepared blue polymer-small molecule hybrid electroluminescence devices with improved
efficiency and lower driving voltage by the statistical design method. Analysis of time-of-flight
measurement shows that amorphous small molecule hole-transporter blended with a blue
light-emitting polymer increases the field-dependent hole mobility, with transition from
nondispersive to dispersive transport induced by the charge-trapping effect. Moreover, at the
electroluminescent devices with different electron injection/transport layer ~LiF/Al, LiF/Ca/Al, and
Alq3 /LiF/Al), efficiency was further increased. We have analyzed that carrier mobility of a
multilayered device can also be controlled by the change of electron injection and transport layers.
We find that structural design and matching overall charge balance is an essential factor to improve
both the operating voltage and efficiency of existing blue polymer devices.