Open AccessHigh efficiency phosphorescence light-emitting diodes with conjugated polymer host
Author(s) -
Qiaoli Niu,
Yong Zhang,
Guanghan Fan
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.8630
Subject(s) - phosphorescence , materials science , conjugated system , pedot:pss , polymer , oled , optoelectronics , photochemistry , doping , quantum efficiency , diode , current density , layer (electronics) , fluorescence , nanotechnology , optics , chemistry , composite material , physics , quantum mechanics
Polymer hosted phosphorescent light-emitting diodes PLEDs were attractive because of their high efficiency light-emission and easy fabrication technology using solution process. For green phosphorescence PLEDsnon-conjugated polymersuch as poly N-vinylcarbazole PVKwere often used as hostwhile conjugated polymer have been proved to quench phosphorescence emission because of their low-lying triplet energy level. In this articlehigh efficiency phosphorescent green-emission was obtained with conjugated polymer of poly 99-dioctylfluorene PFO as host using the device structure of ITO/poly ehtlenedioxythiophene: poly styrene sulfonic acid PEDOT: PSS 50 nm/PVK 40 nm/emissive layer EML 80 nm/Ba 4 nm/Al 150 nm. The EML were PFO doped with different concentration of fac-tris 2-phenylpyridine iridium Ⅲ Irppy3 in weight. The PLED with 2 wt% Irppy3 demonstrated the maximum luminous efficiency of 24.8 cd/A at current density of 4.65 mA/cm2 and power efficiency of 11 lm/w with the peak emission at 520 nm. The luminance reached 35054 cd/m2 at the current density of 265 mA/cm2. According to analyzsisthe hole transport layer PVK can play important role in obtaining highly efficient green light emissingwhose electrons blocking effect resulted in the interfacial emissing center, and then the interfacial PVK enhanced green emission through energy transfer due to its high triplet enery level.