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Naoyuki Nishimura - One of the best experts on this subject based on the ideXlab platform.
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photon upconversion utilizing energy beyond the band gap of crystalline silicon with a hybrid tes adt pbs quantum dots system
Chemical Science, 2019Co-Authors: Victor Gray, Naoyuki Nishimura, Jesse R Allardice, James Xiao, Akshay RaoAbstract:The recent introduction of inorganic semiconductor quantum dots (QDs) as triplet sensitizers for molecular semiconductors has led to significant interest in harvesting low energy photons, which can then be used for photon upconversion (PUC), via triplet–triplet annihilation (TTA). A key goal is the harvesting of photons from below the bandgap of crystalline silicon 1.12 eV (≈1100 nm) and their upconversion into the visible region. In practice, the systems demonstrated so far have been limited to harvesting photons with energies above 1.2 eV (≈1 μm), due to two reasons: firstly the need to use transmitter ligands which allow efficient energy harvesting from the QD but introduce an energy loss of larger than 200 meV in transmission from the QD to the Annihilator, and secondly due to the use of molecules such as tetracene which cannot accept smaller energy than 1.2 eV. Here, we introduce a new strategy to overcome these difficulties by using a low energy triplet Annihilator that also harvests excitations efficiently from QDs. Specifically, we show that 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT, triplet energy of 1.08 eV: ca. 1150 nm) functions as a triplet Annihilator (20% TTA efficiency) while also rapidly extracting triplet excitons from lead sulfide (PbS) QDs with a rate constant of k = ca. 2 × 10−8 s−1 with an excitation at 1064 nm. This rate is consistent with an orbital overlap between TES-ADT and PbS QDs, which we propose is due to the thiophene group of TES-ADT, which enables a close association with the PbS surface, allowing this system to function both as Annihilator and transmitter. Our results pave the way for the design of triplet Annihilators that can closely associate with the QD surface and harvest low energy excitons with minute losses in energy during the TET process, with the ultimate goal of efficiently utilizing photon energy beyond the bandgap of crystalline silicon.
Victor Gray - One of the best experts on this subject based on the ideXlab platform.
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photon upconversion utilizing energy beyond the band gap of crystalline silicon with a hybrid tes adt pbs quantum dots system
Chemical Science, 2019Co-Authors: Victor Gray, Naoyuki Nishimura, Jesse R Allardice, James Xiao, Akshay RaoAbstract:The recent introduction of inorganic semiconductor quantum dots (QDs) as triplet sensitizers for molecular semiconductors has led to significant interest in harvesting low energy photons, which can then be used for photon upconversion (PUC), via triplet–triplet annihilation (TTA). A key goal is the harvesting of photons from below the bandgap of crystalline silicon 1.12 eV (≈1100 nm) and their upconversion into the visible region. In practice, the systems demonstrated so far have been limited to harvesting photons with energies above 1.2 eV (≈1 μm), due to two reasons: firstly the need to use transmitter ligands which allow efficient energy harvesting from the QD but introduce an energy loss of larger than 200 meV in transmission from the QD to the Annihilator, and secondly due to the use of molecules such as tetracene which cannot accept smaller energy than 1.2 eV. Here, we introduce a new strategy to overcome these difficulties by using a low energy triplet Annihilator that also harvests excitations efficiently from QDs. Specifically, we show that 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT, triplet energy of 1.08 eV: ca. 1150 nm) functions as a triplet Annihilator (20% TTA efficiency) while also rapidly extracting triplet excitons from lead sulfide (PbS) QDs with a rate constant of k = ca. 2 × 10−8 s−1 with an excitation at 1064 nm. This rate is consistent with an orbital overlap between TES-ADT and PbS QDs, which we propose is due to the thiophene group of TES-ADT, which enables a close association with the PbS surface, allowing this system to function both as Annihilator and transmitter. Our results pave the way for the design of triplet Annihilators that can closely associate with the QD surface and harvest low energy excitons with minute losses in energy during the TET process, with the ultimate goal of efficiently utilizing photon energy beyond the bandgap of crystalline silicon.
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Porphyrin–Anthracene Complexes: Potential in Triplet–Triplet Annihilation Upconversion
2016Co-Authors: Victor Gray, Bo Albinsson, Karl Börjesson, Damir Dzebo, Maria Abrahamsson, Kasper Moth-poulsenAbstract:Triplet–triplet annihilation photon upconversion (TTA-UC) systems contain both an absorbing and an emitting molecule, the sensitizer and Annihilator, respectively. Through a series of energy-transfer steps, two low frequency photons can be combined into one high frequency photon. In organic solvents, the required energy transfer steps are limited by diffusion and are relatively efficient. In solid-state systems, however, the diffusion is slower, which usually results in lower efficiencies for these systems. An interesting way around this is to connect the sensitizer and Annihilator. In order to increase understanding of the TTA-UC process in supramolecular systems, we synthesized four pyridine-substituted anthracene Annihilators capable of coordinating axially to a zinc octaethylporphyrin sensitizer with a maximum binding constant of 6000 M–1 in toluene. This is a first example of a sensitizer–Annihilator coordination complex for TTA-UC. Both the upconversion efficiency and the parasitic quenching of excited Annihilator singlets by the sensitizer through Förster resonant energy transfer (FRET) were studied. On the basis of the findings herein, possible strategies for future supramolecular TTA systems with minimized FRET quenching are discussed
Jonathan De Roo - One of the best experts on this subject based on the ideXlab platform.
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anthracene diphosphate ligands for cdse quantum dots molecular design for efficient upconversion
Chemistry of Materials, 2020Co-Authors: Daniel N. Congreve, Jonathan De Roo, Zhiyuan Huang, Nathaniel J Schuster, Leslie S Hamachi, Pan Xia, Dmitry A Fishman, Tianquan Lian, Jonathan S OwenAbstract:Quantum dot (QD)-sensitized photon upconversion follows a multi-step energy transfer process from the QD to transmitter ligand to a soluble Annihilator. Using a novel 10-R-anthracene-1,8-diphosphor...
Akshay Rao - One of the best experts on this subject based on the ideXlab platform.
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photon upconversion utilizing energy beyond the band gap of crystalline silicon with a hybrid tes adt pbs quantum dots system
Chemical Science, 2019Co-Authors: Victor Gray, Naoyuki Nishimura, Jesse R Allardice, James Xiao, Akshay RaoAbstract:The recent introduction of inorganic semiconductor quantum dots (QDs) as triplet sensitizers for molecular semiconductors has led to significant interest in harvesting low energy photons, which can then be used for photon upconversion (PUC), via triplet–triplet annihilation (TTA). A key goal is the harvesting of photons from below the bandgap of crystalline silicon 1.12 eV (≈1100 nm) and their upconversion into the visible region. In practice, the systems demonstrated so far have been limited to harvesting photons with energies above 1.2 eV (≈1 μm), due to two reasons: firstly the need to use transmitter ligands which allow efficient energy harvesting from the QD but introduce an energy loss of larger than 200 meV in transmission from the QD to the Annihilator, and secondly due to the use of molecules such as tetracene which cannot accept smaller energy than 1.2 eV. Here, we introduce a new strategy to overcome these difficulties by using a low energy triplet Annihilator that also harvests excitations efficiently from QDs. Specifically, we show that 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT, triplet energy of 1.08 eV: ca. 1150 nm) functions as a triplet Annihilator (20% TTA efficiency) while also rapidly extracting triplet excitons from lead sulfide (PbS) QDs with a rate constant of k = ca. 2 × 10−8 s−1 with an excitation at 1064 nm. This rate is consistent with an orbital overlap between TES-ADT and PbS QDs, which we propose is due to the thiophene group of TES-ADT, which enables a close association with the PbS surface, allowing this system to function both as Annihilator and transmitter. Our results pave the way for the design of triplet Annihilators that can closely associate with the QD surface and harvest low energy excitons with minute losses in energy during the TET process, with the ultimate goal of efficiently utilizing photon energy beyond the bandgap of crystalline silicon.
Jonathan S Owen - One of the best experts on this subject based on the ideXlab platform.
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anthracene diphosphate ligands for cdse quantum dots molecular design for efficient upconversion
Chemistry of Materials, 2020Co-Authors: Daniel N. Congreve, Jonathan De Roo, Zhiyuan Huang, Nathaniel J Schuster, Leslie S Hamachi, Pan Xia, Dmitry A Fishman, Tianquan Lian, Jonathan S OwenAbstract:Quantum dot (QD)-sensitized photon upconversion follows a multi-step energy transfer process from the QD to transmitter ligand to a soluble Annihilator. Using a novel 10-R-anthracene-1,8-diphosphor...