- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Probing Exciton Delocalization in Organic Semiconductors: Insight from Time-Resolved Electron Paramagnetic Resonance and Magnetophotoselection Experiments
摘要： Delocalization of excited states of organic semiconductors is directly related to their e?ciency in devices. Time-resolved electron paramagnetic resonance spectroscopy provides unique capabilities in this respect because of its high spectral resolution and capability to probe the geometry and extent of excitons. Using magnetophotoselection experiments, the mode of exciton delocalization, along the backbone or parallel to the π?π stacking direction of the conjugated polymers, can be revealed. We demonstrate the robustness of this approach by applying it to building blocks of a prototypical conjugated polymer showing a symmetry of their excited states being far from ideal for this experiment. This renders magnetophotoselection superior to other approaches because it is applicable to a wealth of other organic semiconductors. The insight gained into exciton delocalization is crucial to the structure?function relationship of organic semiconductors and directly relevant for developing highly e?cient materials.
关键词： time-resolved electron paramagnetic resonance,conjugated polymers,exciton delocalization,organic semiconductors,magnetophotoselection
更新于2025-09-09 09:28:46
-
Insights into the Efficient Intersystem Crossing of Bodipy-Anthracene Compact Dyads with Steady State and Time-Resolved Optical/Magnetic Spectroscopies and Observation of the Delayed Fluorescence
摘要： Spin-orbit charge transfer induced intersystem crossing (SOCT-ISC) is of particular interest for preparation of heavy atom-free triplet photosensitizers. Up to now examples for SOCT-ISC dyads are limited and electron donor/acceptor SOCT-ISC dyads showing strong visible light-harvesting are rare. Herein we studied the photophysics of a series of Bodipy-anthracene (BDP-An) compact dyads, especially the triplet state electron spin dynamics with the time-resolved electron paramagnetic resonance (TREPR) spectroscopy. The electronic coupling matrix elements (VDA*) between the 1CT (charge transfer) state and 1LE (locally excited) state are in the range 773 cm?1 – 1545 cm?1. For one dyad, we observed three triplet states simultaneously with TREPR, i.e. the triplet states confined on the anthracene (3An) and the Bodipy (3BDP) moieties, as well as a 3CT state. Based on the electron spin polarization (ESP) of these three triplet states and the optical experiments, the SOCT-ISC mechanism is confirmed and the RP-ISC mechanism as the main ISC channel was excluded. Triplet-triplet annihilation (TTA) induced delayed fluorescence was observed for the dyads, which is rare for Bodipy fluorophores.
关键词： intersystem crossing,Bodipy-anthracene dyads,Spin-orbit charge transfer,time-resolved electron paramagnetic resonance,delayed fluorescence,triplet states
更新于2025-09-09 09:28:46