Enhanced Reverse Intersystem Crossing Promoted by Triplet Exciton–Photon Coupling

Abstract

Polaritons are hybrid light−matter states formed via strong coupling between excitons and photons inside a microcavity, leading to upper and lower polariton (LP) bands splitting from the exciton. The LP has been applied to reduce the energy barrier of the reverse intersystem crossing (rISC) process from T 1 , harvesting triplet energy for fluorescence through thermally activated delayed fluorescence. The spin−orbit coupling between T 1 and the excitonic part of the LP was considered as the origin for such an rISC transition. Here we propose a mechanism, namely, rISC promoted by the light−matter coupling (LMC) between T 1 and the photonic part of LP, which is originated from the ISCinduced transition dipole moment of T 1 . This mechanism was excluded in previous studies. Our calculations demonstrate that the experimentally observed enhancement to the rISC process of the erythrosine B molecule can be effectively promoted by the LMC between T 1 and a photon. The proposed mechanism would substantially broaden the scope of the molecular design toward highly efficient cavity-promoted light-emitting materials and immediately benefit the illumination of related experimental phenomena.

Cavity-Free Quantum-Electrodynamic Electron Transfer Reactions

“…The proposed concept is implicitly supported by several previous experimental studies. [45][46][47] Note that the concept of the cavity-free QED-ET reaction is fundamentally different from that of polariton chemistry [7][8][9][10][11][12][13][14][15][16][17][18][19][20] because it accounts for the effect of infinite one-photon states in the absence of strong light-matter interactions. Second, we established a unified theory to describe both radiative and nonradiative ET.…”

“…6 Recently, several experiments demonstrated that QED effects can significantly affect chemical reactions under vibrational strong coupling, [7][8] which goes beyond the scope of traditional chemistry, providing new insights into fundamental science and promoting the development of cavity chemistry (polariton chemistry). [7][8][9][10][11][12][13][14][15][16][17][18][19][20] However, to achieve vibrational strong coupling, specific dielectric environments are required, such as optical cavities or plasmonic cavities, leading to the difficulty of realizing cavity-modified chemical reactions. [21][22][23] Motivated by the recent development of cavity chemistry, we questioned whether it is possible to harness QED effects to control chemical reactions in the absence of cavities.…”

“…This question differs substantially from those in studies on cavity chemistry (or polariton chemistry). [7][8][9][10][11][12][13][14][15][16][17][18][19][20] We believe that this proof-of-concept work will stimulate further investigation of QED-based chemical principles.…”

Cavity quantum-electrodynamical time-dependent density functional theory within Gaussian atomic basis. II. Analytic energy gradient

“…On the other hand, caution should be exerted in the use of these gradients, if the photon field strength or electron-photon coupling g is scaled by p N for a set of N parallel-oriented noninteracting photochromes or by p N/3 for a set of N randomly-oriented photochromes. 65 It is convenient to illustrate this by extending the CIS-JC model to a set of N parallel-oriented non-interacting identical-geometry photochromes. The resultant Tavis-Cummings-type model 25,67 (i.e.…”

Cavity quantum-electrodynamical time-dependent density functional theory within Gaussian atomic basis. II. Analytic energy gradient

“…On the other hand, caution should be exerted in the use of these gradients, if the photon field strength λ or electron-photon coupling g is scaled by √ N for a set of N parallel-oriented noninteracting photochromes or by N/3 for a set of N randomly-oriented photochromes. 65 It is convenient to illustrate this by extending the CIS-JC model to a set of N parallel-oriented non-interacting identical-geometry photochromes. The resultant Tavis-Cummings-type model 25,67 (i.e.…”