低维有机电荷转移共晶的可控组装及电致化学发光性能研究

Organic electrogenerated chemiluminescent (ECL) nanomaterials, which show greatly potential applications for the ultrasensitive detection of the biomolecules (e.g. amino acids) and the rapid diagnosis of some clinical illness, are gradually becoming the research hotspot of the luminescent material field. However, it remains a significant challenge to construct organic semiconductor nanomaterials with both high solid-state luminous efficiency and high charge-transfer capability, which results in weak ECL signal strengths and high working potential, hindering their further development and application in chemical and biological sensing. Organic charge-transfer co-crystals, which may possess simultaneously strong charge-transfer ability and high fluorescence activity, provides a new opportunity for the development of high-efficiency electrochemiluminescent nanostructures. In this project, it is proposed to study the interaction between the organic electrochemiluminescent molecules with the rationally designed organic semiconductors with high charge-transfer rate, and explore the controlled preparation of organic donor-acceptor co-crystal micro/nano-structures, and put forward a synergistic assembly mechanism for the guidance of co-crystal construction. Combining the optical and electrochemical methods, we will further study the relationship between the molecular structure/stacking/co-crystal morphology/photoluminescence/ electrochemiluminescence of the organic donor-acceptor crystal system. This research will not only provide novel strategies and theories for the construction of organic nanomaterials with high ECL intensity, and the development of stable, reusable, highly sensitive ECL chemical/biological sensors.

有机电致化学发光纳米材料，可用于氨基酸等生物分子的高灵敏检测和相关临床疾病的快速诊断，现已成为发光材料领域研究的热点。然而常见的有机电化学发光分子材料，难以兼具高固态发光效率和有效电荷迁移能力，表现出了低的信号强度以及高的工作电位，阻碍了它们在纳米生物传感领域的进一步发展与应用。有机电荷转移共晶，能够兼有高的荧光效率和电荷迁移率，为发展高效电化学发光纳米结构提供了新的契机。本项目拟设计和选择电荷迁移率高的有机半导体分子，研究其与常见有机电化学发光分子的给受体相互作用，探索低维有机电荷转移共晶的可控制备，在此基础上提出具有指导意义的协同组装共晶机理；并结合光学和电化学手段，研究有机给受体共晶体系中分子结构/堆积排布/共晶形貌/光致发光/电化学发光之间的构性关系，为构建具有高电化学发光性能的有机纳米材料，开发稳定、可重复利用、高灵敏的纳米电化学发光生物传器提供新的思路和理论依据。

有机电化学发光（Electrochemiluminescence，ECL）纳米材料，可用于氨基酸等生物分子的高灵敏检测和相关疾病的快速诊断，具有巨大的应用前景。但常见的ECL分子材料，难以兼具高的固态发光效率和电荷迁移能力，展现出了较差的电化学发光性能。本项目利用“二元共结晶”策略，探索常见发光分子与半导体分子之间的协同组装规律，设计制备了较强发光、较高导电的共晶纳米材料，并研究了它们在光致发光、电致化学发光方面的构效关系，构建了高灵敏、双通道的纳米生物传感器。具体如下：1）针对二元共组装中晶型不可控、形貌不规则等问题，我们从内因和外因两方面入手，系统地研究了分子结构、相互作用、温度、浓度等对共晶组装形貌、晶型、分子堆积方式的影响规律，摸索出了一条制备微纳共晶的有效方法，初步阐明了低维共晶组装的一般规律，有望指导新型共晶的设计构筑。2）在光致发光方面，我们可控制备得到了组成相同但分子取向截然不同的二维共晶微结构，类比电子传输行为，首次观察并验证了二维各向同性/各向异性的光致发光行为，并明析了它们的传输机理，解决了半导体光学领域多年来有关“主动光传输对称性与否”的争议问题，也为研究电致发光及传输机理提供了参考。3）在电化学发光方面，我们设计制备了几种电荷转移共晶材料，研究发现，分子间电荷转移作用能在保留分子强发光的同时，增强材料的导电活性，显著提高半导体纳米材料的ECL性能，为构筑高性能的固态ECL传感器提供了一种新的材料和思路。4）首次开发出了一种双色电化学发光微纳异质结构，此异质结构集成了两种不同电化学发光颜色的半导体材料（三联吡啶铱、荧蒽），能各自选择性地响应赖氨酸和半胱氨酸的浓度变化，实现了对两种生物小分子的同时检测。项目执行期间，发表高水平论文1篇（Angew. Chem. Int. Ed., 2020, 59, 4456.），申请国家发明专利2项，培养硕士研究生2名。