A Rational Way to Control the Triplet State Wave Function Confinement of Organic Chromophores: Effect of the Connection Sites and Spin Density Distribution-Guided Molecular Structure Design Principles in Bodipy Dimers.

To study the intersystem crossing (ISC) and the spatial confinement of the triplet excited states of organic chromophores, we prepared a series of Bodipy dimers. We found that the connection position of the two units has a significant effect on the absorption and fluorescence. Singlet oxygen quantum yields of 3.

Does Twisted Molecular Structure Always Induce Intersystem Crossing? A Case Study with Near-IR Absorbing 1,8-Diazabicyclo[5.4.0]undec-7-ene-fused Naphthaldiimide.

Heavy atom-free organic chromophores showing absorption in the near-IR region with intersystem crossing (ISC) ability are important for applications in various fields, e.g., photocatalysis and photodynamic therapy.

Observation of the triplet energy transfer in orthogonal photoexcited iodinated-BODIPY dimers.

Intramolecular charge and energy transfer processes initiated by light absorption can change the photosensitization properties of molecular conjugates. Transient optical and electron paramagnetic resonance (TREPR) spectroscopies are well suited for the study of these processes. In the TREPR spectra of the triplet state of an iodinated BODIPY dimer, we have observed the effect of the averaging of the zero-field (ZFS) parameter , which becomes more efficient with increasing temperature.

Charge Transfer, Intersystem Crossing, and Electron Spin Dynamics in a Compact Perylenemonoimide-Phenoxazine Electron Donor-Acceptor Dyad.

With phenoxazine (PXZ) as the electron donor and perylene-3,4-dicarboximide (PMI) as the electron acceptor, we prepared a compact, orthogonal electron donor-acceptor dyad () to study the spin-orbit charge transfer-induced intersystem crossing (SOCT-ISC). A weak charge transfer (CT) absorption band, due to S → CT transition, was observed (ε = 2840 M cm at 554 nm, FWHM: 2850 cm), which is different from that of the previously reported analogue dyad with phenothiazine as the electron donor (), for which no CT absorption band was observed. A long-lived triplet state was observed (lifetime τ = 182 μs) with nanosecond transient absorption spectroscopy, and the singlet oxygen quantum yield (Φ = 76%) is higher than that of the previously reported analogue dyad (Φ = 57%).

Controlling the triplet states and their application in external stimuli-responsive triplet-triplet-annihilation photon upconversion: from the perspective of excited state photochemistry.

The property of organic light-responsive materials is determined by their electronic excited states to a large extent, for instance, the radiative decay rate constants, redox potentials, and lifetimes. Tuning the excited state properties with external stimuli will lead to versatile functional materials; a representative example is the fluorescence molecular probes, in which the singlet excited states are controlled by the external stimuli, i.e.