Homomolecular non-coherent photon upconversion by triplet-triplet annihilation using a zinc porphyrin on wide bandgap semiconductors

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• 作者：Neeraj Kumar Giri ; Concepcion P. Ponce ; Ronald P. Steer ; ^{ron.steer@usask.ca" class="auth_mail} ; Matthew F. Paige ; ^{matthew.paige@usask.ca" class="auth_mail}
• 刊名：Chemical Physics Letters
• 出版年：8 April, 2014
• 年：2014
• 卷：598
• 期：Complete
• 页码：17-22
• 全文大小：766 K

文摘

Non-coherent upconversion, realized by homomolecular triplet-triplet annihilation of a zinc metalloporphyrin absorber, has been measured for the metalloporphyrin adsorbed on metal oxide films (ZrO₂, TiO₂ and ZrO₂/TiO₂ mixed oxides) in which the semiconductor conduction band energy lies between the metalloporphyrin鈥檚 upconverted and prompt S₁ excited states. Upconverted emission was observed for pure and mixed metal oxide films, regardless of the relative energies of the states, indicating electron transfer from upconverted states to the semiconductor was not competitive. Upconversion was attributed to aggregation of the absorber, likely in defects on the films, leading to efficient homomolecular triplet-triplet annihilation.