C₆₀ is regarded as the most efficient singlet oxygen (¹O₂) photosensitizer. Yet, its oxidation by self-sensitized ¹O₂ remains unclear. The literature hints both oxygen and C₆₀ must be at excited states to react, implying a two-photon process: first, oxygen is photosensitized (¹C₆₀•¹O₂); second, C₆₀ is photoexcited (¹\({\mathrm{C}}_{60}^{\ast}\)•¹O₂). However, this scheme is not plausible in a solvent, which would quench ¹O₂ rapidly before the second photon is absorbed. Here, we uncover a single-photon oxidation mechanism via self-sensitized ¹O₂ in solvents above an excitation energy of 3.7 eV. Using excitation spectroscopies and kinetics analysis, we deduce photoexcitation of a higher energy transient, ³\({\mathrm{C}}_{60}^{{\ast}{\ast}}\)•³O₂, converting to ¹\({\mathrm{C}}_{60}^{\ast}\)•¹O₂. Such triplet-triplet annihilation, yielding two simultaneously-excited singlets, is unique. Additionally, rate constants derived from this study allow us to predict a C₆₀ half-life of about a minute in the atmosphere, possibly explaining the scarceness of C₆₀ in the environment.

C ₆₀被认为是最有效的单线态氧（¹ O ₂）光敏剂。然而，其通过自敏化¹ O ₂的氧化仍不清楚。文献暗示氧气和 C ₆₀都必须处于激发态才能发生反应，这意味着双光子过程：首先，氧气被光敏化 ( ¹ C ₆₀ • ¹ O ₂ )；其次，C ₆₀是光激发的 ( ¹ \({\mathrm{C}}_{60}^{\ast}\) • ¹ O ₂ )。然而，这个方案在溶剂中是不合理的，它会淬灭¹ O ₂在第二个光子被吸收之前迅速。在这里，我们通过在溶剂中激发能量高于 3.7 eV 的自敏化¹ O ₂揭示了单光子氧化机制。使用激发光谱和动力学分析，我们推断出更高能量瞬态的光激发，³ \({\mathrm{C}}_{60}^{{\ast}{\ast}}\) • ³ O ₂，​​转换为¹ \({\mathrm{C}}_{60}^{\ast}\) • ¹ O ₂。这种产生两个同时激发的单线态的三重态-三重态湮灭是独一无二的。此外，从这项研究中得出的速率常数使我们能够预测 C ₆₀在大气中的半衰期约为一分钟，这可能解释了环境中 C ₆₀的稀缺性。