The arguments for converting sunlight and H
2
O to H
2
to provide cleaner fuels and chemicals are very powerful. However, there is still no efficient means of direct solar energy conversion to H
2
on ...a large scale despite a large research effort worldwide. This review describes strategies to develop robust devices which exploit the selectivity of a molecular catalyst but avoids the use of sacrificial electron donors by adsorbing them onto an electrode surface. By assembling the photocathodes with photoanodes, the electrons provided by water oxidation are used to reduce H
+
to H
2
. By separating the functions of light absorption, charge transport and catalysis between the colloidal semiconductor and molecular components, the activity of each can be optimised. However, the complexity of the system requires advanced experimental techniques to evaluate the performance. Current understanding of the factors governing electron transfer across the interface between the semiconductor, dye and catalyst is described and future directions and challenges for this field are outlined.
The arguments for converting sunlight and H
2
O to H
2
to provide cleaner fuels and chemicals are very powerful.
Dye-sensitized solar cells strike back Muñoz-García, Ana Belén; Benesperi, Iacopo; Boschloo, Gerrit ...
Chemical Society reviews,
11/2021, Volume:
5, Issue:
22
Journal Article
Peer reviewed
Open access
Dye-sensitized solar cells (DSCs) are celebrating their 30th birthday and they are attracting a wealth of research efforts aimed at unleashing their full potential. In recent years, DSCs and ...dye-sensitized photoelectrochemical cells (DSPECs) have experienced a renaissance as the best technology for several niche applications that take advantage of DSCs' unique combination of properties: at low cost, they are composed of non-toxic materials, are colorful, transparent, and very efficient in low light conditions. This review summarizes the advancements in the field over the last decade, encompassing all aspects of the DSC technology: theoretical studies, characterization techniques, materials, applications as solar cells and as drivers for the synthesis of solar fuels, and commercialization efforts from various companies.
Dye-sensitized solar cells (DSCs) are celebrating their 30
th
birthday and they are attracting a wealth of research efforts aimed at unleashing their full potential. Righteous font designed by Astigmatic and licensed under the Open Font License.
Dye-sensitized solar cells (DSCs) with cobalt-based mediators with efficiencies surpassing the record for DSCs with iodide-free electrolytes were developed by selecting a suitable combination of a ...cobalt polypyridine complex and an organic sensitizer. The effect of the steric properties of two triphenylamine-based organic sensitizers and a series of cobalt polypyridine redox mediators on the overall device performance in DSCs as well as on transport and recombination processes in these devices was compared. The recombination and mass-transport limitations that, previously, have been found to limit the performance of these mediators were avoided by matching the properties of the dye and the cobalt redox mediator. Organic dyes with higher extinction coefficients than the standard ruthenium sensitizers were employed in DSCs in combination with outer-sphere redox mediators, enabling thinner TiO2 films to be used. Recombination was reduced further by introducing insulating butoxyl chains on the dye rather than on the cobalt redox mediator, enabling redox couples with higher diffusion coefficients and more suitable redox potential to be used, simultaneously improving the photocurrent and photovoltage of the device. Optimization of DSCs sensitized with a triphenylamine-based organic dye in combination with tris(2,2′-bipyridyl)cobalt(II/III) yielded solar cells with overall conversion efficiencies of 6.7% and open-circuit potentials of more than 0.9 V under 1000 W m−2 AM1.5 G illumination. Excellent performance was also found under low light intensity indoor conditions.
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IJS, KILJ, NUK, PNG, UL, UM
Numerous methods exist to analyze complex environmental mixtures in health studies. As an illustration of the different uses of mixture methods, we employed methods geared toward distinct research ...questions concerning persistent organic chemicals (POPs) as a mixture and leukocyte telomere length (LTL) as an outcome.
With information on 18 POPs and LTL among 1,003 U.S. adults (NHANES, 2001-2002), we used unsupervised methods including clustering to identify profiles of similarly exposed participants, and Principal Component Analysis (PCA) and Exploratory Factor Analysis (EFA) to identify common exposure patterns. We also employed supervised learning techniques, including penalized, weighted quantile sum (WQS), and Bayesian kernel machine (BKMR) regressions, to identify potentially toxic agents, and characterize nonlinear associations, interactions, and the overall mixture effect.
Clustering separated participants into high, medium, and low POP exposure groups; longer log-LTL was found among those with high exposure. The first PCA component represented overall POP exposure and was positively associated with log-LTL. Two EFA factors, one representing furans and the other PCBs 126 and 118, were positively associated with log-LTL. Penalized regression methods selected three congeners in common (PCB 126, PCB 118, and furan 2,3,4,7,8-pncdf) as potentially toxic agents. WQS found a positive overall effect of the POP mixture and identified six POPs as potentially toxic agents (furans 1,2,3,4,6,7,8-hxcdf, 2,3,4,7,8-pncdf, and 1,2,3,6,7,8-hxcdf, and PCBs 99, 126, 169). BKMR found a positive linear association with furan 2,3,4,7,8-pncdf, suggestive evidence of linear associations with PCBs 126 and 169, and a positive overall effect of the mixture, but no interactions among congeners.
Using different methods, we identified patterns of POP exposure, potentially toxic agents, the absence of interaction, and estimated the overall mixture effect. These applications and results may serve as a guide for mixture method selection based on specific research questions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Design and synthesis of a minimal bacterial genome Hutchison, Clyde A.; Chuang, Ray-Yuan; Noskov, Vladimir N. ...
Science (American Association for the Advancement of Science),
03/2016, Volume:
351, Issue:
6280
Journal Article
Peer reviewed
Open access
We used whole-genome design and complete chemical synthesis to minimize the 1079-kilobase pair synthetic genome of Mycoplasma mycoides JCVI-syn1.0. An initial design, based on collective knowledge of ...molecular biology combined with limited transposon mutagenesis data, failed to produce a viable cell. Improved transposon mutagenesis methods revealed a class of quasi-essential genes that are needed for robust growth, explaining the failure of our initial design. Three cycles of design, synthesis, and testing, with retention of quasi-essential genes, produced JCVI-syn3.0 (531 kilobase pairs, 473 genes), which has a genome smaller than that of any autonomously replicating cell found in nature. JCVI-syn3.0 retains almost all genes involved in the synthesis and processing of macromolecules. Unexpectedly, it also contains 149 genes with unknown biological functions. JCVI-syn3.0 is a versatile platform for investigating the core functions of life and for exploring whole-genome design.
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BFBNIB, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK
Individual differences in children’s number knowledge arise early and are associated with variation in parents’ number talk. However, there exists little experimental evidence of a causal link ...between parent number talk and children’s number knowledge. Parent number talk was manipulated by creating picture books which parents were asked to read with their children every day for 4 weeks. N = 100 two‐ to four‐year olds and their parents were randomly assigned to read either Small Number (1–3), Large Number (4–6), or Control (non‐numerical) books. Small Number books were particularly effective in promoting number knowledge relative to the Control books. However, children who began the study further along in their number development also benefited from reading the Large Number Books with their parents.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
To build an affordable photoelectrochromic energy conversion unit for self-powered smart window applications, the attractive multi-color Ag/V2O5 electrochromic counter electrode (CE) is coupled with ...a co-sensitized photoanode TiO2/CdS/PbS. V2O5 based devices are well-known for providing smart solutions when a voltage is applied but in this kind of configuration, the quantum dot sensitized solar cell (QDSC) drives the chromatic switching, with sunlight as the natural stimulus. The key objective in coating silver nanowires (AgNW) over the V2O5 film is to enhance the electrochromic as well as electrochemical performance of the device. AgNW impart good electrical conductivity to the layered V2O5 structure making it a promising CE and the transparency of the hybrid film in the visible-light region together with the plasmonic effect contributes to a better optical contrast. The PECD with Ag/V2O5 CE shows a transmission modulation (ΔT) of 31.1% with 45.8 cm2 C-1 coloration efficiency, which is significantly improved than with just V2O5. As compared to the liquid junction photoelectrochromic assembly, the individual films have a much higher ΔT (45.1% at 655 nm). The 5.21% power conversion efficiency (PCE) of the TiO2/CdS/PbS−S2−−Ag/V2O5 QDSC based PECD is a marked rise over that without both AgNW in the CE and PbS near infrared light harvesting QDs at the anode. This work attempts a detailed analysis of the photoelectrochromic and photovoltaic outputs of this novel PECD design with the hybrid film.
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•Self-powered photoelectrochromic device of TiO2/CdS/PbS//Ag/V2O5 is demonstrated.•Highly conducting, plasmonic Ag nanowires enhance optical contrast of the PECD.•Improved electrocatalytic activity of Ag/V2O5 over V2O5 yields superior solar efficiency.•Reversible green to black switching under solar irradiance is demonstrated.•Competitive photocoloration efficiency (∼17%) achieved with low cost components.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Photomodulated voltammetry was used to determine the redox potentials of the diiodide radical (I2 –•) in water, acetonitrile, and 3-methoxypropionitrile. Iodide/triiodide redox electrolytes were ...exposed to modulated blue light, resulting in I2 –• generation. Using transparent fluorine-doped tinoxide (FTO) electrodes, two modulated photocurrent waves could be discerned in the voltammogram, from which the formal potentials for oxidation and reduction reactions of the diiodide radical were determined. E 0′(I2 –•/I–) was found to be +0.79 and +1.04 V versus NHE in acetonitrile and water, respectively. These values give guidelines for E 0′(D+/D) required for efficient regeneration of dyes used in dye-sensitized solar cells .
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IJS, KILJ, NUK, PNG, UL, UM
A way to achieve a high‐efficiency dye‐sensitized solar cell is to combine an n‐type TiO2‐based photoanode with a p‐type photocathode in a tandem configuration. The development of an efficient ...photocathode is, at present, the key target. We have optimized the NiO, I3−/I− p‐DSSC system to obtain record photocurrent, giving 64% incident photon‐to‐current conversion efficiency (IPCE) and 5.48 mAcm−2 JSC.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Counseling researchers often use qualitative research methods to explore phenomena. In particular, lived experience designs seek to answer how, what, and why questions to develop meaning or theory ...from the context and the people who lived the phenomenon. We review four lived experience traditions: phenomenology, consensual qualitative research, narrative inquiry, and case study. The appropriateness of these methods for counseling research and guidelines for design are presented. Recommendations for reporting coherence among the essential elements of a qualitative design are discussed to strengthen counseling researchers' adherence to exemplary practices.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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