Bipolar and Unipolar Silylene-Diphenylene sigma-pi Conjugated Polymer Route for Highly Efficient Electrophosphorescence

作者：Chang Yao Tang; Sharma Sunil; Hung Miao Ken; Lee Yu Hsuan; Chen Show An^*

来源：Scientific Reports, 2016, 6(1): 38404.

DOI：10.1038/srep38404

sigma-pi conjugated polymer strategy is proposed for designing electroluminescent host polymers with silylene-diphenylene as the backbone repeat unit giving a high triplet energy (E-T = 2.67 eV). By incorporation of high E-T (3.0 eV) electron (oxadiazole, OXD) and hole (triphenyl amine, TPA) transport moieties, or TPA alone (in this case, the main chain acts as electron transport channel) as side arms on the silylene, the high E-T bipolar and unipolar polymers are formed, allowing a use of iridium green phosphor (Ir(ppy)2(acac), Ir-G) (E-T = 2.40 eV) as the dopant. The matching of energy levels of the dopant with the hosts, leading to charge trapping into it; and singlets and triplets of the exciplex and excimer can be harvested via energy transfer to the dopant. Using these host-guest systems as the emitting layer, chlorinated indium-tin-oxide (Cl-ITO) as the anode, and benzimidazole derivative (TPBI) as the electron transport layer, this two-layer device gives the high luminance efficiency 80.1 cd/A and external quantum efficiency 21.2%, which is the best among the report values for polymer light emitting diode (PLED) in the literatures. This example manifests that s-p conjugated polymer strategy is a promising route for designing polymer host for efficient electrophosphorescence.

• 出版日期2016-12-2
• 单位清华大学