Tsai, M.-H.M.-H.TsaiKe, T.-H.T.-H.KeLin, H.-W.H.-W.LinCHUNG-CHIH WUChiu, S.-F.S.-F.ChiuFang, F.-C.F.-C.FangLiao, Y.-L.Y.-L.LiaoKEN-TSUNG WONGChen, Y.-H.Y.-H.ChenCHIH-I WU2018-09-102018-09-10200919448244http://www.scopus.com/inward/record.url?eid=2-s2.0-84862832956&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/349313https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862832956&doi=10.1021%2fam800124q&partnerID=40&md5=12b8b12dfa97cf59f44f981e77eaa986Carbazole-based materials adopting the nonconjugated substitution of triphenylsilyl (-SiPh3) and trityl (-CPh3) side groups are studied as high-triplet-energy, morphologically, and electrochemically stable host materials with tunable carrier-transport properties for organic blue electrophosphorescence. The developed host materials 9-(4-tert-butylphenyl)-3,6- bis(triphenylsilyl)-9H-carbazole (CzSi), 9-(4-tert-butylphenyl)-3,6-ditrityl-9H- carbazole (CzC), and 9-(4-tert-butylphenyl)-3-(triphenylsilyl)-6-trityl-9H- carbazole (CzCSi) all show high triplet energies of 2.97-3.02 eV, along with high glass transition temperatures of 131-163 °C and superior electrochemical stability. Nevertheless, the carrier-transport properties show rather significant dependence on different substitutions. Although three different host materials give similar peak electroluminescence efficiencies at low driving currents, the CzSi host, which has more suitable carrier-transport properties, renders broadened distributions of the triplet excitons in phosphorescent devices, reducing the quenching associated with triplet-triplet annihilation and giving larger resistance against efficiency roll-off at higher brightnesses. © 2009 American Chemical Society.application/pdf226592 bytesapplication/pdfblue electrophosphorescence; carbazole; charge transport; host; triphenylsilyl substitution; triplet energy; trityl substitution[SDGs]SDG7carbazole; Charge transport; Electrophosphorescence; host; triphenylsilyl substitution; triplet energy; trityl substitution; Glass transition; Materials; Organic light emitting diodes (OLED); Phosphorescence; Sound insulating materials; Transport properties; Polycyclic aromatic hydrocarbonsjournal article10.1021/am800124q2-s2.0-84862832956WOS:000267535900008