Ultrafast photoresponsive materials for all-optical light modulation by polymer thin films
Ultrafast photoresponsive materials for all-optical light modulation by polymer thin films
复制标题
用于聚合物薄膜全光学光调制的超快光响应材料
DOI：
10.1016/j.polymer.2017.02.051
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发表时间：
2017
期刊：
影响因子：
4.6
通讯作者：
Keiji Tanaka Toshihiko Nagamura
中科院分区：
文献类型：
--
作者：
Tomonori Ono;Kaoru Kawasaki;Keiji Tanaka Toshihiko Nagamura
通过将供体-受体连接分子封装到葫芦单元[8]、CB[8]中作为纳米腔宿主，获得了超快和单指数响应材料。各种芳香族基团通过丙氧基连接基与各种类型的4,4'-联吡啶鎓基团连接。它们在水溶液中表现出具有特定颜色的特征电荷转移（CT）吸收。添加 CB[8] 后，由于 CB[8] 中分子内 CT 复合物的形成，它们显示出明显不同的颜色。在飞秒激光激发 CT 波段时，从供体单元到受体单元发生极快的电子转移，并伴随着可见光到近红外区域的新吸收，这主要是由于光还原联吡啶鎓衍生物所致。 CB[8]中的热背电子转移反应被发现遵循单指数衰减，速率常数范围超过两个数量级，具体取决于供体和受体单元的组合。连接分子中氧化供体和还原受体的速率常数与自由能变化由马库斯理论表达。
Ultrafast and single exponential responsive materials were achieved by encapsulating donor-acceptor linked molecules into cucurbitunitl[8], CB[8], as nanocavity hosts. Various aromatic groups were linked with various types of 4,4′-bipyridinium groups through propyloxy linker. They showed characteristic charge-transfer (CT) absorption with specific colors in aqueous solutions. Upon addition of CB[8], they showed remarkably different colors due to intramolecular CT complex formation in CB[8]. Upon femtosecond laser excitation of CT band extremely fast electron transfer occurred from a donor to an acceptor unit accompanying new absorption in the visible to near-infrared region due mainly to photoreduced bipyridinium derivatives. Thermal back electron transfer reactions in CB[8] were found to follow a single exponential decay with rate constants ranging more than two orders depending on the combination of a donor and an acceptor unit. Their rate constants vs. free energy changes for oxidized donors and reduced acceptors in linked molecules were expressed by the Marcus theory.