芳杂环推拉型大分子的多光子上转换荧光性质  

Multiphoton Upconversion Fluorescence Properties of Heteroaromatic Push-Pull Polymer

作　　者：钱鹰[1] 于文杰[1,2] 吕昌贵[2] 朱晓勤[1] 崔一平[2] 

机构地区：[1]东南大学化学化工学院,南京211189 [2]东南大学电子科学与工程学院,南京210096

出　　处：《物理化学学报》2009年第6期1149-1155,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(60678042;60877024);东南大学科学基金(9207041399)资助

摘　　要：用Wittig反应和Heck反应制备了2个新的芳杂环推-拉型荧光大分子聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4′-乙烯撑-交替-N,N′-二(4-苯乙烯撑)]苯胺(P1)和聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4′-乙烯撑-交替-N-乙基-3,6-咔唑乙烯撑](P2).P1和P2的分解温度分别为373和412℃,热稳定性良好.电化学性能用循环伏安法测定.P1和P2的最高占有分子轨道(HOMO)能级分别为-5.39和-5.81eV,最低未占有分子轨道(LUMO)能级分别为-2.81和-3.09eV.用飞秒Ti:Sapphire激光器测定了P1和P2的三光子和双光子上转换荧光光谱.在1250nm波长激发下,在四氢呋喃溶液中P1和P2的三光子荧光发射峰分别位于510和491nm.在800nm波长激发下,在四氢呋喃溶液中P1和P2的双光子荧光发射峰分别位于511和495nm.在四氢呋喃溶液中大分子P1和P2单光子荧光发射峰分别位于503和475nm,P1和P2的荧光量子产率分别为0.80和0.31.研究了多光子荧光发射过程的溶剂效应.结果表明,溶剂极性增大,P1和P2的多光子荧光发射波长明显红移.Two novel heteroaromatic push-pull fluorescence polymers poly [（2,5-diphenylene-1,3,4-oxadiazole）-4,4＇- vinylene-alt-N,N＇-bis（4-phenylenevinylene）-phenylamine] （P1） and poly [（2,5-diphenylene-l,3,4-oxadiazole）-4,4＇-vinylene- alt-N-ethyl-3,6-carbazolevinylene] （P2） were synthesized by the Wittig reaction and the Heck reaction. Polymers P1 and P2 have decomposition temperatures of 373 and 412℃, respectively, and exhibit good thermal stabilities. Their electrochemical properties were explored by cyclic voltammetry. The highest occupied molecular orbital （HOMO） energy levels of P1 and P2 were -5.39 and -5.81 eV, respectively, and the lowest unoccupied molecular orbital （LUMO） energy levels of P1 and P2 were -2.81 and -3.09 eV, respectively. Three-photon and two-photon upconversion fluorescence spectra of both polymers were measured using a femtosecond Ti：sapphire that was pumped by a femtosecond laser at 1250 and 800 nm. Strong three-photon upconversion fluorescence with maximum emission wavelengths of 510 nm for P1 and 491 nm for P2 in THF solution were observed. By pumping at 800 nm, strong two-photon upconversion fluorescences at 511 nm for P1 and 495 nm for P2 in THF were measured. Maximum peaks of single-photon fluorescence in THF were at 503 nm for P1 and at 475 nm for P2 with fluorescence quantum yields of 0.80 for P1 and 0.31 for P2. The effect of solvent polarity on multi-photon fluorescence was studied. Increased solvent polarity were found to induce a marked red-shift of the emission band in polymers P1 and P2.

关 键 词：芳杂环大分子 上转换荧光 三光子荧光 双光子荧光 溶剂效应 

分 类 号：O621.2[理学—有机化学]