標題: Improving the balance of carrier mobilities of host-guest solid-state light-emitting electrochemical cells
作者: Liao, Chih-Teng
Chen, Hsiao-Fan
Su, Hai-Ching
Wong, Ken-Tsung
照明與能源光電研究所
Institute of Lighting and Energy Photonics
公開日期: 2012
摘要: We report efficient host-guest solid-state light-emitting electrochemical cells (LECs) utilizing a cationic terfluorene derivative as the host and a red-emitting cationic transition metal complex as the guest. Carrier trapping induced by the energy offset in the lowest unoccupied molecular orbital (LUMO) levels between the host and the guest impedes electron transport in the host-guest films and thus improves the balance of carrier mobilities of the host films intrinsically exhibiting electron preferred transporting characteristics. Photoluminescence measurements show efficient energy transfer in this host-guest system and thus ensure predominant guest emission at low guest concentrations, rendering significantly reduced self-quenching of guest molecules. EL measurements show that the peak EQE (power efficiency) of the host-guest LECs reaches 3.62% (7.36 lm W(-1)), which approaches the upper limit that one would expect from the photoluminescence quantum yield of the emissive layer (similar to 0.2) and an optical out-coupling efficiency of similar to 20% and consequently indicates superior balance of carrier mobilities in such a host-guest emissive layer. These results are among the highest reported for red-emitting LECs and thus confirm that in addition to reducing self-quenching of guest molecules, the strategy of utilizing a carrier transporting host doped with a proper carrier trapping guest would improve balance of carrier mobilities in the host-guest emissive layer, offering an effective approach for optimizing device efficiencies of LECs.
URI: http://hdl.handle.net/11536/15321
http://dx.doi.org/10.1039/c1cp23336j
ISSN: 1463-9076
DOI: 10.1039/c1cp23336j
期刊: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Volume: 14
Issue: 3
起始頁: 1262
結束頁: 1269
顯示於類別:期刊論文


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  1. 000299271800018.pdf