Enhanced upconversion emission in air using novel stretched poly(vinyl alcohol) thin films

Mori, Takeshi; Mori, Tomohiro; Saito, Akane; Koishi, Hideyuki; Nakamoto, Chikanobu; Fujii, Akira; Saomoto, Hitoshi

doi:10.1039/c8me00041g

Cited by 8 publications

(10 citation statements)

References 57 publications

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“…The existence of mechanical force can also assist in generating significant luminescence emission and pave a way in constructing novel RTP polymer systems. In 2018, Mori et al [34a] . reported a distinct upconverted blue emission in PVA matrix upon external force stretching.…”

Section: Mechanochromic Polymer Systemsmentioning

confidence: 99%

Stimuli‐Responsive Polymers with Room‐Temperature Phosphorescence

2022

Chemistry A European J

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Taking advantages of the impressing behaviors of room‐temperature phosphorescence (RTP), the explorations in RTP materials are not only limited to efficient emission and ultralong lifetime of phosphorescence. The discovery and creation of stimuli‐responsive properties have become the major pursuit, which will lay a solid foundation for future applications in RTP materials. Based on this, a review centered on recent progress of stimuli‐responsive RTP materials is summarized to show frontier development in polymer systems. Different kinds of stimuli‐responsive factors including light, oxygen, temperature, mechanical force and pH regulations are investigated in this review. Many potential applications and promising strategies are deeply discussed with the hope to assist future studies in this area.

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Section: Mechanochromic Polymer Systemsmentioning

confidence: 99%

Stimuli‐Responsive Polymers with Room‐Temperature Phosphorescence

2022

Chemistry A European J

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“…To date, several approaches to creating solid state UC systems have been reported, including blending of chromophores in polymer matrix (stretched poly(vinyl alcohol) (PVA), , melt-pressing poly(methyl methacrylate) (PMMA)), , π-conjugated polymers, − using quasi-solid organogels and immobilizing chromophores on ZrO 2 . Compared to solid systems, using gel matrices affords triplet transfer by molecular diffusion within the trapped solvent, making them more analogous to liquid-state systems.…”

Section: Introductionmentioning

confidence: 99%

“…Blending chromophores into polymer matrices, while avoiding undesirable aggregation, is an attractive approach to meet the requirements of efficient Dexter-type energy transfer. Methods proposed and realized for TTA-UC in rigid polymer matrices include doping into PMMA or PVA, which have been shown to efficiently upconvert light, even under ambient conditions without additional encapsulation. ,, A melt-press method was reported by Lee et al, yielding a >20 wt % loading of chromophores in PMMA, which helped overcome poor TET yields in the rigid matrix. In spite of these attempts increased UC quantum yields, they remain at least an order of magnitude lower compared to solution-based systems, highlighting the continuing challenges in developing solid-based TTA-UC systems and encouraging us to search for new material combinations and new strategies for combining them.…”

Section: Introductionmentioning

confidence: 99%

Solid State Photon Up-Conversion Emission from Chromophore-Tethered PPV Films

et al. 2021

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Solid state triplet–triplet annihilation (TTA) upconversion (UC) systems may find application as elements in a wide range of practical photon energy conversion technologies. One strategy to produce highly efficient UC emission in the solid state is to create systems that can efficiently transport generated triplets to distances significantly longer than afforded by the Dexter mechanism under restriction of molecular movement. In this work, we present a new solid state UC system through integration of conjugated poly(p-phenylene vinylene) (PPV) derivatives, with tethered and/or blended chromophores of (9,10-bisphenylethynylanthracene (BPEA) as an emitter and palladium(II) meso-tetraphenyltetrabenzoporphyrine (TBP)) as a sensitizer. Photoluminescence spectroscopy reveals that the introduction of a small ratio (ca. 3%) of covalently bound BPEA onto the PPV backbone enhances UC emission around an order of magnitude compared to the homo-PPV when mixed with 2 wt % TBP. On the other hand, time-resolved measurements find more rapid consumption of the generated sensitizer triplets with BPEA increased concentrations (up to 50 mol %), suggesting that these BPEA units provide accelerated triplet energy transfer (TET) compared to in homo-PPV, however there exists a significant loss channel via energy back transfer in PPV-BPEA with higher contents of the BPEA unit. Moreover, microsecond time scale decay behavior, where a small population of triplets exist, show that triplets were mainly transmitted through the conjugated polymer phase.

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“…In our previous work, we reported a new method for embedding chromophores into an ultralow oxygen permeability poly(vinyl alcohol) (PVA) matrix by a wet-stretching technique for a solid UC system. 22 Interestingly, the stretched PVA films showed significantly enhanced UC emission under air with increasing elongation length, despite no UC emission occurring from the nonstretched PVA films. We proposed that the chromophores accumulated in the PVA amorphous regions during stretching, allowing triplet excitons to easily migrate for subsequent annihilation.…”

mentioning

confidence: 97%

“…Their synthetic procedures and optical properties are described in our previous work, except for the counter cations of WS-TPP. 22 In this work, to simplify the overall protocol, aqueous chromophore tetraalkylammonium salts were prepared and readily blended into aqueous PVA. Therefore, tetrabutylammonium cations were introduced to both WS-TPP and WS-DPA.…”

mentioning

confidence: 99%

Effect of Crystallinity in Stretched PVA Films on Triplet–Triplet Annihilation Photon Upconversion

Mori

Fujii

et al. 2020

ACS Appl. Polym. Mater.

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A wet-stretching technique was applied to chromophore-blended poly(vinyl alcohol) (PVA) films to control the agglomeration of chromophores and improve the triplet−triplet annihilation (TTA) photon upconversion (UC) performance of the solid-state system. By using the stretching technique, a maximum UC quantum yield of ∼3% and lowest threshold intensity of 90 mW/cm 2 were obtained under atmospheric conditions. It was found that a decrease in the crystallinity of the PVA matrix induced by stretching caused specific localization of the chromophores and accelerated triplet energy transfer and triplet exciton migration.

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Enhanced upconversion emission in air using novel stretched poly(vinyl alcohol) thin films

Abstract: The mechanical stretching process enhances the upconversion emission of chromophore-blended poly(vinyl alcohol) films under an air atmosphere.

Cited by 8 publications

References 57 publications

Stimuli‐Responsive Polymers with Room‐Temperature Phosphorescence

Stimuli‐Responsive Polymers with Room‐Temperature Phosphorescence

Solid State Photon Up-Conversion Emission from Chromophore-Tethered PPV Films

Effect of Crystallinity in Stretched PVA Films on Triplet–Triplet Annihilation Photon Upconversion

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