Affiliation:
1. Key Laboratory of Organic Integrated Circuits Ministry of Education Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of Chemistry School of Science Tianjin University Tianjin 300072 China
2. Functional Crystal Lab Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China
3. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
4. College of Chemistry Chemical Engineering and Materials Science Key Laboratory of Molecular and Nano Probes Ministry of Education Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong Shandong Normal University Jinan 250014 China
Abstract
AbstractTwo‐photon excited fluorescence imaging requires high‐performance two‐photon absorption (TPA) active materials, which are commonly intramolecular charge transfer systems prepared by traditional chemical synthesis. However, this typically needs harsh conditions and new methods are becoming crucial. In this work, based on a collaborative intermolecular charge transfer (inter‐CT) strategy, three centimeter‐sized organic TPA cocrystals are successfully obtained. All three cocrystals exhibit a mixed stacking arrangement, which can effectively generate inter‐CT between the donor and acceptor. The ground and excited state characterizations compare their inter‐CT ability: 1,2‐BTC > 2D‐BTC > 1D‐BTC. Transient absorption spectroscopy detects TCNB•−, indicating that the TPA mechanism arises from molecular polarization caused by inter‐CT. Meanwhile, 1,2‐BTC exhibits the highest excited‐state absorption and the longest excited‐state lifetime, suggesting a stronger TPA response. First‐principles calculations also confirm the presence of inter‐CT interactions, and the significant parameter Δµ which can assess the TPA capability indicates that inter‐CT enhances the TPA response. Besides, cocrystals also demonstrate excellent water solubility and two‐photon excited fluorescence imaging capabilities. This research not only provides an effective method for synthesizing TPA crystal materials and elucidates the connection between inter‐CT ability and TPA property but also successfully applies them in the fields of multi‐photon fluorescence bioimaging.
Funder
National Natural Science Foundation of China
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry