Free-triplet generation with improved efficiency in tetracene oligomers through spatially separated triplet pair states

Efficient singlet fission in nanoparticles of amphipathic anthracene–tetracene dyad with broadband light harvesting ability

“…Two PIA bands at ∼417 nm and 588–700 nm region (the main peak at ∼650 nm) were detected, which is corresponding to the S 1 state absorption. 42,53 Similarly, an increase in the intensity of the S 1 absorption at 417 nm was detected within 50 ps (Fig. S5, ESI†), which should also be brought by vibrational cooling and rotation of the two phenyl rings at the 5,12-position of DPT in the S 1 state.…”

Revealing the contest between triplet-triplet exchange and triplet-triplet energy transfer coupling in correlated triplet pair states in singlet fission

“…In the future, however, when considering spin mixing interactions, these need to be included since spin dipolar interactions are also in the µeV range. 22,41 Each of these couplings are computed using a single spin flip CAS calculation.…”

“…39,40 Formation of the 1 (T...T) has recently been shown to improve the final triplet yield in covalently linked tetracene trimers and tetramers. 41 The purpose of this manuscript is two fold: First, we present an efficient ab initio-based technique to characterize the multi-excitonic states in terms of a simple model Hamiltonian consisting of physically meaningful quantities, t and K. This model Hamiltonian, in turn, allows us to identify values of t and K which lead to favorable energetics for dissociation of the (TT) state into independent triplet excitons. Second, we perform numerical calculations to resolve the connection between chromophore packing and the t and K parameters to identify which geometries might be preferable for efficient triplet separation.…”

Quantum dynamics simulation of intramolecular singlet fission in covalently linked tetracene dimer

“…This is achieved by chemical modification of the bridging group and tuning of the solvent environment. For example, Wang et al, recently reported fast iSF within 10 ps in covalent tetracene dimers linked by phenyl groups as in Figure 1 and illustrated its temperature dependence and significant solvent polarity effects 9 . It is nowadays well-known that a pure electronic description is insufficient to describe these processes correctly 2,3,[20][21][22] , suggesting the necessity of the incorporation of molecular vibrations into theoretical considerations.…”

“…Previous theoretical and experimental studies [9][10][11][12][13][14][15][16][17][18] investigated the mechanism behind SF and distinguished between coherently driven and thermally activated SF, where only the latter exhibits a strong temperature dependence. The different mechanisms happen on different time-scales, namely up to 700 fs for coherently driven SF 18 and > 1 ps for thermally actived SF 17 .…”