Fureraj Ina, Wega Johannes, Balanikas Evangelos, Puji Pamungkas Khurnia Krisna, Sakai Naomi, Matile Stefan, Vauthey Eric
Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland.
Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland.
J Phys Chem Lett. 2024 Aug 8;15(31):7857-7862. doi: 10.1021/acs.jpclett.4c01840. Epub 2024 Jul 25.
The torsional disorder of conjugated dyes in the electronic ground state can lead to inhomogeneous broadening of the S ←S absorption band, allowing for the selective photoexcitation of molecules with different amounts of distortion. Here, we investigate how this affects electronic transitions to upper excited states. We show that torsion of a core-alkynylated push-pull dye can have opposite effects on the oscillator strength of its lowest-energy transitions. Consequently, photoselection of planar and twisted molecules can be achieved by exciting in distinct absorption bands. Whereas this has limited effect in liquids due to fast planarization of the excited molecules, it strongly affects the overall photophysics in a polymeric environment, where torsional motion is hindered, allowing for the photoselection of molecules with different fluorescence quantum yields and intersystem-crossing dynamics.
共轭染料在电子基态下的扭转无序会导致S←S吸收带的非均匀展宽，从而实现对具有不同扭曲程度分子的选择性光激发。在此，我们研究了这如何影响到上激发态的电子跃迁。我们表明，核心炔基化推拉染料的扭转对其最低能量跃迁的振子强度可能产生相反的影响。因此，通过在不同的吸收带进行激发，可以实现平面分子和扭曲分子的光选择。鉴于在液体中由于激发分子的快速平面化，这种效应有限，但在聚合物环境中它会强烈影响整体光物理过程，在聚合物环境中扭转运动受到阻碍，从而实现对具有不同荧光量子产率和系间窜越动力学的分子的光选择。
