Applications and Prospects for Triplet–Triplet Annihilation Photon Upconversion

Rauch, Martin P.; Knowles, Robert R.

doi:10.2533/chimia.2018.501

Cited by 21 publications

(31 citation statements)

References 48 publications

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“…The same mechanism is used for sensitizing * anna.koehler@uni-bayreuth.de semiconductor photocatalysts using the broad-spectrum sunlight [10,11]. TTA sensitized photon up-conversion is also advantageous in the fields of biomedical applications such as photoinduced drug delivery and photodynamic therapy [12,13]. In particular, up-conversion of red light with increased penetration in biological systems into blue light that is required for most photochemical reactions has been proved to be highly relevant [14].…”

Section: Introductionmentioning

confidence: 99%

Kinetic Monte Carlo Study of Triplet-Triplet Annihilation in Conjugated Luminescent Materials

et al. 2020

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It is well known that in organic solids the collision of two excitons can give rise to delayed fluorescence (DF). Revived interest in this topic is stimulated by the current endeavor towards the development of efficient organic optoelectronic devices such as organic light-emitting diodes (OLEDs) and solar cells, or sensitizers used in photodynamic therapy. In such devices, triplet excitations are ubiquitously present but their annihilations can be either detrimental, e.g., giving rise to a roll-off of intensity in an OLED, or mandatory, e.g., if the sensitizer relies on up-conversion of long-lived low-energy triplet excitations. Since the employed materials are usually noncrystalline, optical excitations migrate via incoherent hopping. Here, we employ kinetic Monte Carlo simulations (KMC) to study the complex interplay of triplet-triplet annihilation (TTA) and quenching of the triplet excitations by impurities in a single-component system featuring a Gaussian energy landscape and variable system parameters such as the length of the hopping sites, i.e., a conjugated oligomer, the morphology of the system, the degree of disorder (σ ), the concentration of triplet excitations, and temperature. We also explore the effect of polaronic contributions to the hopping rates. A key conclusion is that the DF features a maximum at a temperature that scales with σ/k B T. This is related to disorder-induced filamentary currents and thus locally enhanced triplet densities. We predict that a maximum for the TTA process near room temperature or above requires typically a disorder parameter of at least 70 meV.

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Section: Introductionmentioning

confidence: 99%

Kinetic Monte Carlo Study of Triplet-Triplet Annihilation in Conjugated Luminescent Materials

et al. 2020

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“…FVB mice were inoculated in the back with 1×10e 6 human breast adenocarcinoma cells (MCF). When the tumors reached a volume of approximately 125 mm 3 , TTA-UC-PLGA-NPs were injected intravenously in the tail vein.…”

Section: Resultsmentioning

confidence: 99%

“… In vivo imaging of TTA-UC-PLGA-NPs. (a) FVB mice were inoculated in the back with 1×10e 6 MCF-7 cells. When the tumors reached a size of ∼125 mm 3 , mice were injected intravenously in the tail vein with 0.5mg of TTA-UC-PLGA-NPs and imaged 3, 24, 48, 72 and 98 hours post injection using the IVIS imaging system.…”

Section: Resultsmentioning

confidence: 99%

“…In the last decade, photon upconversion (UC), a process that converts low-energy into high-energy light 2,3 , has become state-of-art in the field of in vitro and in vivo biomedical imaging due to several unique optical properties: i) large hypsochromic shift, ii) sharp emission peak, iii) long luminescence shelf-life and iv) high photostability 4-6 . Photon UC is a combination of photophysical processes and it can be achieved via different energy transfer mechanisms using different materials, such as rare-earth metals, metalloporphyrins and organic polyaromatic hydrocarbons 2,3 .…”

Section: Introductionmentioning

confidence: 99%

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Triplet-Triplet Annihilation PLGA-Nanoparticles for Cancer Bioimaging

Vepris

Eich

Feng

et al. 2020

Preprint

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Triplet-triplet annihilation upconversion (TTA-UC) nanoparticles (NPs) have emerged as imaging probes and therapeutic probes in recent years due to their excellent optical properties. In contrast to lanthanide ions-doped inorganic materials, highly efficient TTA-UC can be generated by low excitation power density, which makes it suitable for clinical applications. In the present study, we used biodegradable poly(lactic-co-glycolic acid) (PLGA)-NPs as delivery vehicle for TTA-UC based on the heavy metal porphyrin Platinum(II) octaethylporphyrin (PtOEP) and the polycyclic aromatic hydrocarbon 9,10-diphenylanthracene (DPA) as photosensitizer/emitter pair. TTA-UC-PLGA-NPs were successfully synthesized according to an oil-in-water emulsion and solvent evaporation method. After physicochemical characterization, UC-efficacy of TTA-UC-PLGA-NPs was assessed in vitro and ex vivo. TTA-UC could be detected in the tumor area 96 hours after in vivo administration of TTA-UC-PLGA-NPs, confirming the integrity and suitability of PLGA-NPs as TTA-UC in vivo delivery system. Thus, this study provides proof-of-concept that the advantageous properties of PLGA can be combined with the unique optical properties of TTA-UC for the development of advanced nanocarriers for simultaneous in vivo molecular imaging and drug delivery.

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“…For instance, trapping of population in dark triplet states reduces the fluorescence quantum yield of molecules and materials, which is a major issue in applications such as the development of efficient organic light-emitting diodes ( Chang et al., 2013 ) and luminescent carbon nanotubes ( Zhao and Mazumdar, 2004 ). Because of their metastable nature, triplet states can also be used to store energy; this capability plays an important role in applications such as the frequency upconversion of low-intensity light ( Rauch and Knowles, 2018 ) and superresolved optical imaging ( Bretschneider et al., 2007 ). Triplet states can also be harnessed for their chemical reactivity, as in photosensitization ( Zhao et al., 2013 ) and photopolymerization ( Chi et al., 2019 ; Harke et al., 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Elucidating complex triplet-state dynamics in the model system isopropylthioxanthone

et al. 2022

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Summary We introduce techniques for probing the dynamics of triplet states. We employ these tools, along with conventional techniques, to develop a detailed understanding of a complex chemical system: a negative-tone, radical photoresist for multiphoton absorption polymerization in which isopropylthioxanthone (ITX) is the photoinitiator. This work reveals that the same color of light used for the 2-photon excitation of ITX, leading to population of the triplet manifold through intersystem crossing, also depletes this triplet population via linear absorption followed by reverse intersystem crossing (RISC). Using spectroscopic tools and kinetic modeling, we identify the reactive triplet state and a non-reactive reservoir triplet state. We present compelling evidence that the deactivation channel involves RISC from an excited triplet state to a highly vibrationally excited level of the electronic ground state. The work described here offers the enticing possibility of understanding, and ultimately controlling, the photochemistry and photophysics of a broad range of triplet processes.

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Applications and Prospects for Triplet–Triplet Annihilation Photon Upconversion

Cited by 21 publications

References 48 publications

Kinetic Monte Carlo Study of Triplet-Triplet Annihilation in Conjugated Luminescent Materials

Kinetic Monte Carlo Study of Triplet-Triplet Annihilation in Conjugated Luminescent Materials

Triplet-Triplet Annihilation PLGA-Nanoparticles for Cancer Bioimaging

Elucidating complex triplet-state dynamics in the model system isopropylthioxanthone

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