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Updated: Oct 13, 2025

Triplet Fusion Upconversion Nanocapsule Synthesis
Published on: September 7, 2022
Near-Unity Triplet Generation Promoted via Spiro-Conjugation
Meng Lv1, Xicun Lu2, Yanrong Jiang1
1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China.
Abstract:
An intersystem crossing (ISC) rate constant of 1.0×1011 s-1 was previously registered with a spiro-bis-benzophenone scaffold. Triplet generation efficiency could be further enhanced by stabilizing the spiro-charge-transfer (CT) state and rationally designing spiro-compounds (SCTs) that consist of electron-rich diphenyl ether as the spiro-CT donor and electron-deficient dinaphthyl ketone as the spiro-CT acceptor. Through fine-tuning of the energy level between the CT and high energy triplet states, near-unity triplet generation quantum yield was achieved and the underlying ISC mechanism is revealed by using ultrafast spectroscopy and quantum chemical calculations. Potential triplet sensitizing application was demonstrated in SCTs. Our findings suggest that a spiro-bichromophoric molecular system with an enhanced spiro-charge transfer warrants efficient triplet generation and is a powerful strategy of heavy-atom-free triplet sensitizers with predictable ISC properties.
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