Affiliation:
1. Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
2. Current address: Department of Biology and Chemistry Osnabrück University Barbarastraße 7 49076 Osnabrück Germany
3. Current address: Division of Chemical Physics Department of Chemistry Lund University Box 124 22100 Lund Sweden
Abstract
AbstractPhotosensitizers for sensitized triplet‐triplet annihilation upconversion (sTTA‐UC) often rely on precious heavy metals, whereas coordination complexes based on abundant first‐row transition metals are less common. This is mainly because long‐lived triplet excited states are more difficult to obtain for 3d metals, particularly when the d‐subshell is only partially filled. Here, we report the first example of sTTA‐UC based on a 3d6 metal photosensitizer yielding an upconversion performance competitive with precious metal‐based analogues. Using a newly developed Cr0 photosensitizer featuring equally good photophysical properties as an OsII benchmark complex in combination with an acetylene‐decorated anthracene annihilator, red‐to‐blue upconversion is achievable. The upconversion efficiency under optimized conditions is 1.8 %, and the excitation power density threshold to reach the strong annihilation limit is 5.9 W/cm2. These performance factors, along with high photostability, permit the initiation of acrylamide polymerization by red light, based on radiative energy transfer between delayed annihilator fluorescence and a blue light absorbing photo‐initiator. Our study provides the proof‐of‐concept for photon upconversion with elusive first‐row analogues of widely employed precious d6 metal photosensitizers, and for their application in photochemical reactions triggered by excitation wavelengths close to near‐infrared.
Funder
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Deutsche Forschungsgemeinschaft
Danmarks Frie Forskningsfond
Carlsbergfondet
Subject
General Chemistry,Catalysis
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献