| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Hu, Maowei, et al.
(författare)
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Efficient and Stable Dye-Sensitized Solar Cells Based on a Tetradentate Copper(II/I) Redox Mediator
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:36, s. 30409-30416
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Tidskriftsartikel (refereegranskat)abstract
- The identification of an efficient and stable redox mediator is of paramount importance for commercialization of dye-sensitized solar cells (DSCs). Herein, we report a new class of copper complexes containing diamine-dipyridine tetradentate ligands (L1 = N,N'-dibenzyl-N,N'-bis-(pyridin-2-ylmethyl)ethylenediamine; L2 = N,N'-dibenzyl-N,N'-bis (6-methyl-pyridin-2-ylmethyl)ethylenediamine) as redox mediators in DSCs. Devices constructed with [Cu(L2)](2+/+) redox couple afford an impressive power conversion efficiency (PCE) of 9.2% measured under simulated one sun irradiation (100 mW cm(-2), AM 1.5G), which is among the top efficiencies reported thus far for DSCs with copper complex-based redox mediators. Remarkably, the excellent air, photo, and electrochemical stability of the [Cu(L2)](2+/+) complexes renders an outstanding long-term stability of the whole DSC device, maintaining similar to 90% of the initial efficiency over 500 h under continuous full sun irradiation. This work unfolds a new platform for developing highly efficient and stable redox mediators for large-scale application of DSCs.
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| 3. |
- Li, Fei, et al.
(författare)
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Integration of FeOOH and Zeolitic Imidazolate Framework-Derived Nanoporous Carbon as an Efficient Electrocatalyst for Water Oxidation
- 2018
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Ingår i: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- As a cost-effective catalyst for the oxygen evolution reaction (OER), the potential use of FeOOH is hindered by its intrinsic poor electron conductivity. Here, the significant enhancement of OER activity and long-term stability of electrodeposited FeOOH on zeolitic imidazolate framework-derived N-doped porous carbons (NPCs) are reported. In alkaline media, FeOOH/NPC supported on nickel foam as a 3D electrode delivers a current density of 100 mA cm(-2) at a small overpotential of 230 mV and exhibits a low Tafel slope of 33.8 mV dec(-1) as well as excellent durability, making it one of the most active OER catalysts. Such high performance is attributed to a combined effect of the excellent electron conductivity of NPC and the synergy between FeOOH and NiO derived from Ni substrate.
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| 4. |
- Wang, Mei, et al.
(författare)
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Visible-light-absorbing semiconductor/molecular catalyst hybrid photoelectrodes for H-2 or O-2 evolution : recent advances and challenges
- 2017
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Ingår i: Sustainable Energy & Fuels. - : ROYAL SOC CHEMISTRY. - 2398-4902. ; 1:8, s. 1641-1663
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Forskningsöversikt (refereegranskat)abstract
- The research on the conversion of solar energy and its storage as an eco-friendly and momentarily available chemical fuel, such as H-2, by sunlight-driven water splitting is closely related to the sustainable development of the global economy and to the continuous improvement of the modern living standards of human beings. One of the most promising approaches to sunlight-driven water splitting is to construct a dual-illuminated photoelectrochemical (PEC) cell by integrating a photoanode with a photocathode in a tandem configuration. To this end, the important work is to individually develop highly efficient, durable, inexpensive, and readily scalable photoanodes and photocathodes for each half reaction of water splitting, either O-2 or H-2 evolution reaction (OER or HER). A promising approach emerging in recent years towards OER photoanodes and HER photocathodes is the immobilization of molecular catalysts (MC) onto the surface of visible-light-absorbing semiconductor (VLASC) electrodes. Very recently, some encouraging results have been achieved in the construction of MC-modified VLASC photoanodes and photocathodes. This review is focused on the recent advances in hybrid photoelectrodes for OER and HER, which were built by the integration of MCs with VLASC materials. After a brief introduction of three major units, viz. VLASC materials, MCs, and anchor groups, used to date for fabricating hybrid photoelectrodes for OER and HER, the construction strategy and the performance of the VLASC/MC photoanodes and photocathodes are described in two respective chapters. Finally, challenges and developments in future studies of VLASC/MC hybrid photoelectrodes are discussed.
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| 5. |
- Zhao, Yawei, et al.
(författare)
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Fine-tuning the coordination atoms of copper redox mediators : an effective strategy for boosting the photovoltage of dye-sensitized solar cells
- 2019
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 7:20, s. 12808-12814
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Tidskriftsartikel (refereegranskat)abstract
- Natural systems have marvelously utilized copper complexes featuring sulfur-coordinating ligands, known as blue copper proteins, as efficient electron-transfer mediators in biological processes. Copper complexes with sulfur-coordinating ligands have been attempted as redox mediators in dye-sensitized solar cells (DSCs), the performance of which is not yet satisfactory and still remains less well explored. Herein, we report the application of new copper complexes bearing a tetradentate polythioether ligand, [(S-4)Cu](2+/+) (1(2+/+), S-4 = 1,4,8,11-tetrathiocyclotetradecane), as a redox mediator in DSCs in comparison with its N-4-tetradentate counterpart [(N-4)Cu](2+/+) (2(2+/+), N-4 = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). Impressively, the changes of coordination atoms from N to S positively shift the formal redox potential of the copper complexes by 600 mV, leading to a remarkably high photovoltage approaching 1.0 V. This is one of the highest photovoltage values reported thus far for DSCs based on copper redox mediators.
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