Highly Efficient Blue-Light-Emitting Glass-Forming Molecules Based on Tetraarylmethane/Silane and Fluorene: Synthesis and Thermal, Optical, and Electrochemical Properties

详细信息    查看全文

• 作者：Xue-Ming Liu ; Chaobin He ; Junchao Huang ; and Jingmei Xu
• 刊名：Chemistry of Materials
• 出版年：2005
• 出版时间：January 25, 2005
• 年：2005
• 卷：17
• 期：2
• 页码：434 - 441
• 全文大小：166K
• 年卷期：v.17,no.2(January 25, 2005)
• ISSN：1520-5002

文摘

The paper reports the first blue-light-emitting tetrahedral glass-forming molecules derived from fluoreneand several tetrahedral core compounds. The glass-forming molecules (5-8) were prepared from threetetrabromo cores of X(p-ArBr)₄ (X = C, Si; Ar = -C₆H₄-, -C₆H₄C₆H₄-) and an octabromo core of tetra(2,4-dibromobiphenyl-4'-yl)methane with 9,9-dihexylfluorene-2-MgBr via Grignard coupling reactions.Compounds 5-8 exhibited obvious glass transition behaviors with T_gs in the range of 85-147 C anddisplayed high thermal stabilities with T_ds in the range of 329-385 C. Compounds 5-8 exhibited strongabsorptions in solution with _max at 318-326 nm and log at 5.95-6.28. The emission maxima of thesecompounds in THF were in the range of 377-405 nm with high PL quantum yields of 79-100%. UnderUV light excitation, their spin-coated films emitted intense blue-light peaking at 405-415 nm with quantumyields of 25-98%. The films emitted relatively pure blue light with small fwhm (full width at half-maximum) values of 57-75 nm and absences of excimer-like long wavelength emissions, due to thenonaggregating property of the tetrahedral compounds in the solid state. The two Si-centered moleculesexhibited better film-forming property and much higher film PL quantum efficiencies than their C-centeredcounterparts. The present tetrahedral molecules would represent a novel class of nonaggregating blue-light-emitting molecular glass-forming materials based on the fluorene fluorophore that were easilysynthesized by a one-step Grignard coupling reaction.