文摘
The positive external heavy atom effect on upconversion efficiency (桅uc) of DPA (9,10-diphenylanthracene) emitter combined with palladium(II)tetraphenylporphyrins as triplet sensitizer was first found to significantly increase from 12.33% to 35.17% under excitation of low power density at 30 mW路cm鈥? (位ex = 532 nm). Dynamics data showed that the increasing phosphorescence lifetime (蟿p) and the phosphorescence quantum yield (桅p) of sensitizer, accompanied with the decreasing nonphosphorescence decay rate constant (knp), have contribution to the triplet鈥搕riplet energy transfer (TTT). Interestingly, the external heavy atom effect was found to be more efficient than the internal heavy atom effect on upconversion efficiency, which has provided a simple approach to increase low-powered upconversion efficiency without the difficulties that can arise by the modification of the sensitizer molecular structure in its inner parts. Moreover, this efficient green-to-blue upconversion has been demonstrated to have potential application for the hydrogen-generation from water under excitation of sun energy.