Background
Regional citrate anticoagulation (RCA) is recommended for continuous renal replacement therapy (CRRT). However, filter life varies and premature filter clotting can occur. The aims of this ...explorative prospective study were to investigate the effects of RCA on thrombin generation, fibrinolysis and platelet function in critically ill patients receiving CRRT, to compare clotting parameters between systemic and intra-circuit blood samples, and to screen participants for coagulation disorders. We recruited critically ill adult patients admitted to a 30-bedded Intensive care unit in a tertiary care hospital who required CRRT with RCA for acute kidney injury (AKI). Patients with pre-existing thrombotic, bleeding tendencies or a CRRT duration less than 48 h were excluded. We measured coagulation and thrombophilia parameters at baseline. Thrombin generation, D-dimer and platelet function were measured pre-CRRT and at 12, 24, 36, 48 and 72 h after commencing CRRT using blood samples taken from the arterial line and the circuit.
Results
At baseline, all eleven patients (mean age 62.4 years, 82% male) had Factor VIII and von Willebrand Factor concentrations above reference range and significantly increased peak thrombin generation. During CRRT, there were no significant changes in systemic maximum peak thrombin generation, time to peak thrombin generation, fibrinogen, D-dimer and platelet function analysis. We observed no significant difference between paired samples taken from the patient's arterial line and the circuit.
Conclusions
Critically ill patients with AKI requiring CRRT are hypercoagulable. Citrate used for anticoagulation during CRRT does not affect thrombin generation, D-dimer or platelet function. Systemic clotting parameters reflect intra-circuit results.
Trial registration
: ClinicalTrials.gov Identifier: NCT02486614.
Registered 01 July 2015—Registered after recruitment of first patient.
https://clinicaltrials.gov/ct2/show/NCT02486614
Highlights
Critical issues including mechanical stability, water and oxygen resistance, transparent electrodes for flexible perovskite solar cells are discussed.
Roll-to-Roll technology presents a ...promising avenue for fabrication of flexible perovskite solar cells fabricated for large-scale commercial application.
Balancing the transmittance and conductivity of transparent electrodes has become a significant issue in developing efficient flexible perovskite solar cells.
The demand for building-integrated photovoltaics and portable energy systems based on flexible photovoltaic technology such as perovskite embedded with exceptional flexibility and a superior power-to-mass ratio is enormous. The photoactive layer, i.e., the perovskite thin film, as a critical component of flexible perovskite solar cells (F-PSCs), still faces long-term stability issues when deformation occurs due to encountering temperature changes that also affect intrinsic rigidity. This literature investigation summarizes the main factors responsible for the rapid destruction of F-PSCs. We focus on long-term mechanical stability of F-PSCs together with the recent research protocols for improving this performance. Furthermore, we specify the progress in F-PSCs concerning precise design strategies of the functional layer to enhance the flexural endurance of perovskite films, such as internal stress engineering, grain boundary modification, self-healing strategy, and crystallization regulation. The existing challenges of oxygen-moisture stability and advanced encapsulation technologies of F-PSCs are also discussed. As concluding remarks, we propose our viewpoints on the large-scale commercial application of F-PSCs.
This work focuses on the extraction of the open circuit voltage (V
) on photovoltaic nanowires by surface photovoltage (SPV) based on Kelvin probe force microscopy (KPFM) measurements. In a first ...approach, P-I-N radial junction (RJ) silicon nanowire (SiNW) devices were investigated under illumination by KPFM and current-voltage (I-V) analysis. Within 5%, the extracted SPV correlates well with the V
. In a second approach, local SPV measurements were applied on single isolated radial junction SiNWs pointing out shadowing effects from the AFM tip that can strongly impact the SPV assessment. Several strategies in terms of AFM tip shape and illumination orientation have been put in place to minimize this effect. Local SPV measurements on isolated radial junction SiNWs increase logarithmically with the illumination power and demonstrate a linear behavior with the V
. The results show notably that contactless measurements of the V
become feasible at the scale of single photovoltaic SiNW devices.
This work focuses on the extraction of the open circuit voltage (
V
OC
) on photovoltaic nanowires by surface photovoltage (SPV) based on Kelvin probe force microscopy (KPFM) measurements. In a first ...approach, P-I-N radial junction (RJ) silicon nanowire (SiNW) devices were investigated under illumination by KPFM and current-voltage (I-V) analysis. Within 5%, the extracted SPV correlates well with the
V
OC
. In a second approach, local SPV measurements were applied on single isolated radial junction SiNWs pointing out shadowing effects from the AFM tip that can strongly impact the SPV assessment. Several strategies in terms of AFM tip shape and illumination orientation have been put in place to minimize this effect. Local SPV measurements on isolated radial junction SiNWs increase logarithmically with the illumination power and demonstrate a linear behavior with the
V
OC
. The results show notably that contactless measurements of the
V
OC
become feasible at the scale of single photovoltaic SiNW devices.
Perovskite photovoltaic has been attracting intense attention as an emerging technology due to its figure of merits including high power conversion efficiency, low-cost fabrication, and others. A ...successful commercialization of this type of technology has been significantly retarded by issues of elemental toxicity and device stability which are related to the key component of lead (Pb) in most efficient halide perovskites. Here, we first elucidated the origin of the superior optoelectronic properties of lead halide perovskites and their impact on photovoltaic device performance. We then discussed the promising approaches to solve the toxicity issue of lead hybrid perovskites. We further outlooked the effective solutions for lead hybrid perovskites for solar cell application. This review may provide a guidance for researchers interested in facilitating perovskite solar cells from exploitation to application.
This review elucidates the origin of the superior optoelectronic properties of lead halide perovskites and their impact on photovoltaic device performance.The importance of Lead to Perovskites Photovoltaics. Display omitted
•The importance of lead to the superior optoelectronic properties of lead halide perovskites and their impact on photovoltaic device performance has been elucidated.•The promising approaches to solve the toxicity issue of lead hybrid perovskites are discussed.•The effective solutions for lead hybrid perovskites for solar cell application is further outlooked.
Phosphate solubilizing fungi (PSF) have huge potentials in enhancing release of phosphorus from fertilizer. Two PSF (NJDL-03 and NJDL-12) were isolated and identified as Penicillium oxalicum and ...Aspergillus niger respectively in this study. The quantification and identification of organic acids were performed by HPLC. Total concentrations of organic acids secreted by NJDL-03 and NJDL-12 are ~4000 and ~10,000 mg/L with pH values of 3.6 and 2.4 respectively after five-days culture. Oxalic acid dominates acidity in the medium due to its high concentration and high acidity constant. The two fungi were also cultured for five days with the initial pH values of the medium varied from 6.5 to 1.5. The biomass reached the maximum when the initial pH values are 4.5 for NJDL-03 and 2.5 for NJDL-12. The organic acids for NJDL-12 reach the maximum at the initial pH = 5.5. However, the acids by NJDL-03 continue to decrease and proliferation of the fungus terminates at pH = 2.5. The citric acid production increases significantly for NJDL-12 at acidic environment, whereas formic and oxalic acids decrease sharply for both two fungi. This study shows that NJDL-12 has higher ability in acid production and has stronger adaptability to acidic environment than NJDL-03.
This study reports on the surface charge transfer doping of narrow-bandgap Sn/Pb binary metal perovskites to controllably tune the carrier concentration and electrical properties, and therefore ...reduce the energy disorder. The excess holes on the Sn/Pb binary metal perovskite surface can be compensated by the applied benzyl viologen (BV in short) molecules to reduce the self-p-doping hole density. Consequently, the doping level of the BV-modified Sn-Pb perovskite films was carefully altered from heavy p-type to less p-type with up-shifted Fermi level and considerably reduced the surface energetic disorder, which effectively suppressed the nonradiative recombination at the perovskite/electron transport layer interface. The perovskite solar cells (PSCs) using narrow-bandgap FA
0.7
MA
0.3
Sn
0.5
Pb
0.5
I
3
exhibited dramatically enhanced photovoltaic performance with an optimized power conversion efficiency (PCE) up to 22.58%, thus representing one of the highest PCE among Sn/Pb binary metal PSCs reported so far. Furthermore, combining the narrow-bandgap (1.25 eV) FA
0.7
MA
0.3
Sn
0.5
Pb
0.5
I
3
bottom sub-cell with a wide-bandgap (1.78 eV) Cs
0.2
FA
0.8
PbI
1.8
Br
1.2
top sub-cell, the best performing 2-terminal all-perovskite tandem solar cell achieved a prominent PCE of 26.33%. Moreover, the optimized tandem device exhibited excellent long-term stability by retaining 88.3% of the initial PCE following 1000 h of operation at the maximum power point under 1-sun illumination.
This study reports on the surface charge transfer doping of narrow-bandgap Sn/Pb binary metal perovskites with benzyl viologen. The as-fabricated all perovskite two-terminal tandem solar cell exhibits a power conversion efficiency of 26.33%.
•For the first time thiophene derivative as interface modifier is reported for CsSnI3 perovskite solar cells.•The 3-thiophenemethylammonium iodide can autonomously inter-connect with uncoordinated ...Sn2+via lone electron pairs of the donated π electrons.•The interface modifier lowers electron extraction potential barrier at perovskite/ electron transport layer junction.•The optimized CsSnI3 planar solar cell exhibited a power conversion efficiency of 12.05 % under AM 1.5G illumination condition.
Eco-friendly all-inorganic tin halide perovskite compounds have drawn significant attention for photovoltaic applications. Nevertheless, the non-radiative recombination derived from the uncoordinated Sn2+ cations at surface and the electron extraction barrier between different functional layers significantly impair the performance of perovskite device. Here we for the first time show that thiophene derivative, 3-thiophenemethylammonium iodide, as an interface modifier between the CsSnI3 perovskite surface and electron transport layer, can passivate defects and reduce the electron extraction potential barrier. The molecules of 3-thiophenemethylammonium iodide can autonomously inter-connect with uncoordinated Sn2+via lone electron pairs of the donated π electrons in electronic-rich thiophene molecule. Moreover, such interface modifier lowers the electron extraction potential barrier at the perovskite/electron transport layer junction in which an interface dipole electric field form. Consequently, the optimized planar solar cell with a structure of ITO/PEDOT:PSS/CsSnI3/ICBA/BCP/Ag, exhibited a power conversion efficiency of 12.05 % under AM 1.5G illumination condition. To the best of our knowledge, this is the highest efficiency for fully inorganic CsSnI3-based devices reported so far. This study represents an innovative approach to realize high-efficiency all-inorganic CsSnI3 perovskite solar cells.
All-inorganic tin halide perovskite compounds, such as CsSnI3, have attracted attention in the field of solar cells due to their eco-friendly properties. It is quite a challenge to fabricate ...high-quality CsSnI3 perovskite films with low defect density due to the low defect tolerance and overquick crystallization growth rate. Herein, we propose a simple yet effective method to modulate the dynamic balance between the growth and nucleation of perovskite crystals for black orthorhombic phase CsSnI3. We found that well-crystallized CsSnI3 thin films can be easily obtained through two-step thermal annealing at low temperatures of 40 °C and 70 °C. We further introduced 1-(4-carboxyphenyl)-2-thiourea to coordinate with surface undercoordinated Sn2+ cations of CsSnI3 thin films through C=S and C=O functional groups, significantly decreasing the defect density. The CsSnI3 perovskite solar cells based on a printable c-TiO2/m-TiO2/Al2O3/NiO/carbon mesoporous framework achieved a power conversion efficiency of 8.03% with high reproducibility, which is the best efficiency among those reported for all-inorganic CsSnI3 mesoporous perovskite solar cells to date. Furthermore, the corresponding devices retained 90% of the initial efficiency after 3000 hours of storage in a N2-filled glovebox.
Fully inorganic perovskite cesium lead triiodide (CsPbI3) has garnered much attention from researcher for photovoltaic application because of its excellent thermal stability compared with the ...inorganic‐organic hybrid counterparts, along with the potential to serve as the top cell in tandem devices with silicon solar cell. However, the active α‐phase cubic CsPbI3 spontaneously tends to transform into the non‐perovskite δ‐CsPbI3 when subjected to ambient condition. This work proposes an effective method to fabricate high‐quality and stable α‐phase cubic CsPbI3 films by introducing phosphorus pentachloride (PCl5) as an additive. PCl5 acts as colloidal binder for modulating crystallization dynamics of perovskites, resulting in high‐quality film and a significantly suppressed phase transition. Finally, highly stable CsPbI3 perovskite solar cells can be achieved with a power conversion efficiency up to 17.85 %, and a long‐term stability in N2 filled glove box.
Better crystallization, better performance: High‐quality α‐CsPbI3 film can be obtained by introducing phosphorus pentachloride as an additive in synthesis, which acts as a colloidal coupling agent to increases the size of CsPbI3 soft framework units and thus slows down the crystals crystallization rate to ensure a grain growth.
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