Organic using triplet-state acceptor

This process is known as photosensitization and should only be significant in dilute solutions of the acceptor and donor for long-lived triplet states, which for typical organic molecules have lifetimes of 10" to 10 sec versus only 10 to 10 sec for excited singlet states. Photosensitized reactions are also often used to describe non-energy transfer reactions these will be discussed in Section 4.2.1. 

Use of photoexcited fullerenes (i.e., the singlet or triplet excited state) widens the scope of electron-transfer reactions. This assumption is because excitation of fullerenes enhances both the electron-acceptor and -donor behavior of the photoexcited fullerenes. For example, the triplet excited state of C o, which is formed by efficient intersystem crossing (i.e. with a quantum yield close to unity) [18, 19] has a reduction potential of E°red = 1.14 V relative to the SCE [18, 19]. This potential is clearly more positive than the reduction potential of the ground state (—0.43 V) [20]. Thus, the triplet excited state of Ceo can be reduced with a variety of organic compounds yielding the Cgo radical anion and the oxidized donor [18]. 

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