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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
2.
A band-gap-graded CZTSSe solar cell with 12.3% efficiency Yang, Kee-Jeong; Son, Dae-Ho; Sung, Shi-Joon ...
Journal of materials chemistry. A, Materials for energy and sustainability,
01/2016, Volume:
4, Issue:
26
Journal Article
Peer reviewed
Although Cu sub(2)ZnSn(S,Se) sub(4) (CZTSSe) has attracted attention as an alternative to CuInGaSe sub(2) (CIGS) as an absorber material in solar cells, its low efficiency is a serious shortcoming ...preventing its commercialization. To realize a high-efficiency CZTSSe solar cell, improved grain crystallinity, inhibited secondary-phase formation, controlled defect generation, adequate Na content, and band gap grading are required in the absorber layer. Few studies have focused specifically on band gap grading. In this study, a method of using SeS sub(2), a new potential chalcogenization source material, to control the S and Se contents in a CZTSSe absorber and its effects were investigated. Using an appropriate SeS sub(2)/Se weight ratio, band gap grading was realized within the depletion region. By increasing the value of V sub(OC) through band gap grading in the depletion region, a record V sub(OC) deficit of 0.576 V was achieved. Furthermore, the possibility of enhancing J sub(SC) through the formation of a type-inverted n-type phase at the absorber surface in response to an appropriate alignment of the conduction-band minimum energy level and the Fermi energy pinning level is discussed. By introducing the chalcogenization source material SeS sub(2) during the annealing process, CZTSSe solar cells with a maximum efficiency of 12.3% were obtained.
We report highly efficient Cu2ZnSn(S,Se)4 (CZTSSe) thin films with a power conversion efficiency (PCE) of 12.3% at their surface and interface. The structural and electrical properties were locally ...investigated, using scanning probe microscopy and micro‐Raman scattering, to improve the performance of kesterite solar cells. Interestingly, this research reports quite different results from the conventional kesterite solar cells, owing to the observance of undesirable voids and secondary phases. Nonetheless, the solar cells exhibit a high PCE of over 12%. Thus, we probe the kesterite solar cells as a function of the depth and introduce a mechanical dimple‐etching process. The relatively low melting temperature of the pure‐metal precursors results in the unique properties within the solar cell materials. Understanding these phenomena and their effects on carrier behavior enables the achievement of a higher PCE and better performance for kesterite solar cells.
The high‐efficient kesterite thin film, grown by pure‐metal precursors, has unique phase distribution through the thin film, compared to the one by S compound precursors. The CZTSSe thin films show secondary phases and few voids between the absorber and the Mo layer. The altered current flow path in the solar cells, however, can result in the enhanced solar cell efficiency.
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One of the characteristic features of aging is the progressive loss of muscle mass, a nosological syndrome called sarcopenia. It is also a pathologic risk factor for many clinically adverse outcomes ...in older adults. Therefore, delaying the loss of muscle mass, through either boosting muscle protein synthesis or slowing down muscle protein degradation using nutritional supplements could be a compelling strategy to address the needs of the world's aging population. Here, we review the recently identified properties of docosahexaenoic acid (DHA). It was shown to delay muscle wasting by stimulating intermediate oxidative stress and inhibiting proteasomal degradation of muscle proteins. Both the ubiquitin-proteasome and the autophagy-lysosome systems are modulated by DHA. Collectively, growing evidence indicates that DHA is a potent pharmacological agent that could improve muscle homeostasis. Better understanding of cellular proteolytic systems associated with sarcopenia will allow us to identify novel therapeutic interventions, such as omega-3 polyunsaturated fatty acids, to treat this disease.
Protopanaxadiol (PPD), an aglycon found in several dammarene-type ginsenosides, has high potency as a pharmaceutical. Nevertheless, application of these ginsenosides has been limited because of the ...high production cost due to the rare content of PPD in
and a long cultivation time (4-6 years). For the biological mass production of the PPD, de novo biosynthetic pathways for PPD were introduced in
and the metabolic flux toward the target molecule was restructured to avoid competition for carbon sources between native metabolic pathways and de novo biosynthetic pathways producing PPD in
. Here, we report a CRISPRi (clustered regularly interspaced short palindromic repeats interference)-based customized metabolic flux system which downregulates the lanosterol (a competing metabolite of dammarenediol-II (DD-II)) synthase in
. With the CRISPRi-mediated suppression of lanosterol synthase and diversion of lanosterol to DD-II and PPD in
, we increased PPD production 14.4-fold in shake-flask fermentation and 5.7-fold in a long-term batch-fed fermentation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The 26S proteasome, a self-compartmentalized protease complex, plays a crucial role in protein quality control. Multiple levels of regulatory systems modulate proteasomal activity for substrate ...hydrolysis. However, the destruction mechanism of mammalian proteasomes is poorly understood. We found that inhibited proteasomes are sequestered into the insoluble aggresome via HDAC6- and dynein-mediated transport. These proteasomes colocalized with the autophagic receptor SQSTM1 and cleared through selective macroautophagy, linking aggresomal segregation to autophagic degradation. This proteaphagic pathway was counter-balanced with the recovery of proteasomal activity and was critical for reducing cellular proteasomal stress. Changes in associated proteins and polyubiquitylation on inhibited 26S proteasomes participated in the targeting mechanism to the aggresome and autophagosome. The STUB1 E3 Ub ligase specifically ubiquitylated purified human proteasomes in vitro, mainly via Lys63-linked chains. Genetic and chemical inhibition of STUB1 activity significantly impaired proteasome processing and reduced resistance to proteasomal stress. These data demonstrate that aggresomal sequestration is the crucial upstream event for proteasome quality control and overall protein homeostasis in mammals.
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Juvenile hormones (JHs) play a central role in insect development, reproduction, and various physiological functions. Curcuminoids generally exhibit a wide range of biological activities, such as ...antioxidant, anti-inflammatory, antibacterial, and insecticidal, and they exhibit insect growth inhibitory effects. However, research on insecticidal properties of curcuminoids has been limited. Moreover, to the best of our knowledge, studies on JHs of insects and curcuminoids are lacking. Therefore, this study aimed to identify the substances that act as JH disruptors (JHDs) from edible plants. Demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), two curcuminoids from the turmeric plant
L. inhibited the formation of a methoprene-tolerant (Met)-Taiman (Tai) heterodimer complex in
, as shown through in vitro yeast two-hybrid assays. An artificial diet containing 1% (
/
) DMC or BDMC significantly reduced the number of
larvae in a concentration-dependent manner; larval development was disrupted, preventing the progression of larvae to pupal stages, resulting in an absence of adults. Building on the results obtained in this study on curcuminoids, researchers can use our study as a reference to develop eco-friendly pesticides.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We found a clear correlation between the solar conversion efficiency and the distribution of the ZnS secondary phase in Cu2ZnSnS4 (CZTS) solar cells. Five CZTS solar cells were prepared by the ...two-step process in which sputtered precursor multilayers were sulfurized at different temperatures. In higher efficiency solar cells, the ZnS secondary phase was found to accumulate near the interface between CZTS and MoS2 formed on top of the Mo layer. It was also found that a solar cell with a higher efficiency showed weaker ZnS Raman signal in the MoS2 layer. The highest conversion efficiency of 7.5% was obtained from a solar cell prepared at a sulfurization temperature of 570°C, in which no ZnS was detected in the MoS2 layer. We suggest that in order to obtain a high efficiency CZTS solar cell, it is critical to find a condition that keeps ZnS from the MoS2 layer.
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•ZnS in the MoS2 layer of Cu2ZnSnS4 solar cells reduces the efficiency.•In a high efficiency cell, no ZnS was detected in the MoS2 layer.•ZnS tends to accumulate in the CZTS layer near the CZTS/MoS2 interface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The CZTS-based absorber layer exhibits lower current characteristics than the CIGSe-based absorber layer in terms of the band gap alignment and electron-hole recombination at the CdS-absorber layer ...interface. Moreover, we demonstrate that defects are one of the causes of the voltage loss. The defects caused by secondary phases inside the CZTS-based absorber layer exhibit a deep energy level inside the band gap and act as electron-hole recombination centers and strong electron-trapping centers. Therefore, in order to improve the efficiency of CZTS-based thin-film solar cells, it is important to control the band gap alignment at the CdS-absorber layer interface and to suppress the formation of secondary phases inside the absorber. ▪
In this study, we investigate methods of improving the efficiency of Cu2ZnSn(S,Se)4 (CZTS)-based solar cells by comparing Cu(In,Ga)Se2 (CIGSe)- and CZTS-based absorber layers. In particular, the CZTS-based absorber exhibits lower current characteristics than the CIGSe absorber layer in terms of the band gap alignment and electron-hole recombination at the CdS-absorber interface. Moreover, we demonstrate that defects are one of the causes of the voltage loss. In order to improve the efficiency of CZTS-based solar cells, it is important to control the band gap alignment at the CdS-absorber layer interface and to suppress the formation of secondary phases inside the absorber.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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