| 1. |
- Bharmoria, Pankaj, 1985, et al.
(author)
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Photon upconverting bioplastics with high efficiency and in-air durability
- 2021
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In: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7534 .- 2050-7526. ; 9:35, s. 11655-11661
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Journal article (peer-reviewed)abstract
- There is an urgent demand for substituting synthetic plastics to bioplastics for sustainable renewable energy production. Here, we report a simple one-step approach to create bioplastics with efficient and durable photon upconversion (UC) by encapsulating non-volatile chromophore solutions into collagen-based protein films. By just drying an aqueous solution of gelatin, surfactant, and UC chromophores (sensitizer and annihilator), liquid surfactant microdroplets containing the UC chromophores are spontaneously confined within the gelatin films. Thanks to the high fluidity of microdroplets and the good oxygen barrier ability of the collagen-based fiber matrices, a high absolute TTA-UC efficiency of 15.6% and low threshold excitation intensity of 14.0 mW cm−2are obtained even in air. The TTA-UC efficiency was retained up to 8.2% after 2 years of storage under ambient conditions, hence displaying the significant durability desired for practical applications.
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| 2. |
- Bharmoria, Pankaj, 1985, et al.
(author)
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Recyclable optical bioplastics platform for solid state red light harvesting via triplet-triplet annihilation photon upconversion
- 2022
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7496 .- 2050-7488. ; 10:40, s. 21279-21290
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Journal article (peer-reviewed)abstract
- Sustainable photonics applications of solid-state triplet-triplet annihilation photon upconversion (TTA-UC) are limited by a small UC spectral window, low UC efficiency in air, and non-recyclability of polymeric materials used. In a step to overcome these issues, we have developed new recyclable TTA-UC bioplastics by encapsulating TTA-UC chromophores liquid inside the semicrystalline gelatin films showing broad-spectrum upconversion (red/far-red to blue) with high UC efficiency in air. For this, we synthesized a new anionic annihilator, sodium-TIPS-anthracene-2-sulfonate (TIPS-AnS), that combined with red/far-red sensitizers (PdTPBP/Os(m-peptpy)(2)(TFSI)(2)), a liquid surfactant Triton X-100 reduced (TXr) and protein gelatin (G) formed red/far-red to blue TTA-UC bioplastic films just by air drying of their aqueous solutions. The G-TXr-TIPS-AnS-PdTPBP film showed record red to blue (633 to 478 nm) TTA-UC quantum yield of 8.5% in air. The high UC quantum yield has been obtained due to the fluidity of dispersed TXr containing chromophores and oxygen blockage by gelatin fibers that allowed efficient diffusion of triplet excited chromophores. Further, the G-TXr-TIPS-AnS-Os(m-peptpy)(2)(TFSI)(2) bioplastic film displayed far-red to blue (700-730 nm to 478 nm) TTA-UC, demonstrating broad-spectrum photon harvesting. Finally, we demonstrated the recycling of G-TXr-TIPS-AnS-PdTPBP bioplastics by developing a downstream approach that gives new directions for designing future recyclable photonics bioplastic materials.
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| 3. |
- Wang, Zhihang, 1989, et al.
(author)
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Demonstration of an azobenzene derivative based solar thermal energy storage system
- 2019
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 7:25, s. 15042-15047
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Journal article (peer-reviewed)abstract
- Molecules capable of reversible storage of solar energy have recently attracted increasing interest, and are often referred to as molecular solar thermal energy storage (MOST) systems. Azobenzene derivatives have great potential as an active MOST candidate. However, an operating lab scale experiment including solar energy capture/storage and release has still not been demonstrated. In the present work, a liquid azobenzene derivative is tested comprehensively for this purpose. The system features several attractive properties, such as a long energy storage half-life (40 h) at room temperature, as well as an excellent robustness demonstrated by optically charging and discharging the molecule over 203 cycles without any sign of degradation (total operation time of 23 h). Successful measurements of solar energy storage under simulated sunlight in a microfluidic chip device have been achieved. The identification of two heterogeneous catalyst systems during testing enabled the construction of a fixed bed flow reactor demonstrating catalyzed back-conversion from cis to trans azobenzene at room temperature under flow conditions. The working mechanism of the more suitable catalytic candidate was rationalized by detailed density functional theory (DFT) calculations. Thus, this work provides detailed insights into the azobenzene based MOST candidate and identifies where the system has to be improved for future solar energy storage applications.
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| 4. |
- Wang, Zhihang, 1989, et al.
(author)
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Liquid-Based Multijunction Molecular Solar Thermal Energy Collection Device
- 2021
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In: Advanced Science. - : Wiley. - 2198-3844 .- 2198-3844. ; 8:21
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Journal article (peer-reviewed)abstract
- Photoswitchable molecules-based solar thermal energy storage system (MOST) can potentially be a route to store solar energy for future use. Herein, the use of a multijunction MOST device that combines various photoswitches with different onsets of absorption to push the efficiency limit on solar energy collection and storage is explored. With a parametric model calculation, it is shown that the efficiency limit of MOST concept can be improved from 13.0% to 18.2% with a double-junction system and to 20.5% with a triple-junction system containing ideal, red-shifted MOST candidates. As a proof-of-concept, the use of a three-layered MOST device is experimentally demonstrated. The device uses different photoswitches including a norbornadiene derivative, a dihydroazulene derivative, and an azobenzene derivative in liquid state with different MOSTproperties, to increase the energy capture and storage behavior. This conceptional device introduces a new way of thinking and designing optimal molecular candidates for MOST, as much improvement can be made by tailoring molecules to efficiently store solar energy at specific wavelengths.
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