Publications by authors named "Takafumi Horikoshi"
For realization of efficient organic light-energy conversion systems, controlling the lifetime of photogenerated charge separated states in donor (D)-acceptor (A) molecules is of much importance; the spin dynamics is one of the important controlling factors. We previously reported that the covalently-linked 1,3-bis(2-pyridylimino)-isoindolate platinum (BPIPt)-dimethoxytriphenylamine (D)-naphthaldiimide (A) triad molecule (BPIPt-DA) exhibits a triplet-born long-lived charge separated state (BPIPt-DA), the lifetime of which is significantly increased from 4 µs to 10 µs by an applied magnetic field of 270 mT in room temperature tetrahydrofuran (THF). The purpose of the present study is to clarify detailed dynamics of spin-dependent generation and the decay of BPIPt-DA.
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- The study focuses on the charge-separated (CS) state dynamics of a new molecular triad made up of a donor (D), a platinum complex (BPIPt), and an acceptor (A) connected by a benzene unit.
- Photoexcitation of BPIPt leads to a long-lived CS state (about 4 microseconds), which is further stabilized when a magnetic field is applied, indicating a transition of the spin state from singlet to triplet.
- The effects of the platinum complex are minimal on the electronic and magnetic properties, suggesting that the structural design contributes to the observed phenomena without significantly altering charge recombination dynamics.
Photoinduced electron transfer was studied in dyads (dyad1 and dyad2) containing triphenylamine (MTA) and naphthalenediimide (MNDI) linked with oligo(phenyleneethynylene) dispersed in rigid polymer matrices of polystyrene (PS), poly(vinyl chloride), and poly(methyl methacrylate). Photoexcitation of these dyads yielded long-lived charge-separated (CS) states involving MTA and MNDI. The quantum yields of charge separation in dyad1 and dyad2 were approximately 0.
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