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1.
ACS Appl Mater Interfaces ; 6(17): 15448-55, 2014 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-25137502

RESUMO

Among the issues that restrict the power conversion efficiency (PCE) of quantum-dot-sensitized solar cells (QDSSCs), insufficient catalytic activity and stability of counter electrodes (CEs) are critical but challenging ones. The state-of-the-art Cu/Cu2S CEs still suffer from mechanical instability and uncertainty due to the reaction of copper and electrolyte. Herein, ITO@Cu2S core-shell nanowire arrays were developed to fabricate CEs for QDSSCs, which have no such issues in Cu/Cu2S CEs. These nanowire arrays exhibited small charge transfer resistance and sheet resistance, and provided more active catalytic sites and easy accessibility for electrolyte due to the three-dimensional structure upon use as CEs. More interestingly, it was found that the interface of ITO/Cu2S significantly affected the performance of ITO@Cu2S nanowire array CEs. By varying synthetic methods, a series of ITO@Cu2S nanowire arrays were prepared to investigate the influence of ITO/Cu2S interface on their performance. The results showed that ITO@Cu2S nanowire array CEs with a continuous Cu2S nanocrystal shell fabricated via an improved cation exchange route exhibited excellent and thickness-dependent performance. The PCE of corresponding QDSSCs increased by 11.6 and 16.5% compared to that with the discrete Cu2S nanocrystal and the classic Cu/Cu2S CE, respectively, indicating its promising potential as a new type of CE for QDSSCs.

2.
Nano Lett ; 14(1): 365-72, 2014 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-24350879

RESUMO

Quantum-dot-sensitized solar cell (QDSSC) has been considered as an alternative to new generation photovoltaics, but it still presents very low power conversion efficiency. Besides the continuous effort on improving photoanodes and electrolytes, the focused investigation on charge transfer at interfaces and the rational design for counter electrodes (CEs) are recently receiving much attention. Herein, core-shell nanowire arrays with tin-doped indium oxide (ITO) nanowire core and Cu2S nanocrystal shell (ITO@Cu2S) were dedicatedly designed and fabricated as new efficient CEs for QDSSCs in order to improve charge collection and transport and to avoid the intrinsic issue of copper dissolution in popular and most efficient Cu/Cu2S CEs. The high-quality tunnel junctions formed between n-type ITO nanowires and p-type Cu2S nanocrystals led to the considerable decrease in sheet resistance and charge transfer resistance and thus facilitated the electron transport during the operation of QDSSCs. The three-dimensional structure of nanowire arrays provided high surface area for more active catalytic sites and easy accessibility for an electrolyte. As a result, the power conversion efficiency of QDSSCs with the designed ITO@Cu2S CEs increased by 84.5 and 33.5% compared to that with planar Au and Cu2S CEs, respectively.

3.
Chem Asian J ; 8(10): 2483-8, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23846962

RESUMO

The tremendous future energy demand and environmental concerns prompt the lasting search for new materials for low-cost and high-efficiency solar cells. SnS, as a low-cost, earth-abundant, and environmentally friendly material with proper band gap and absorption coefficient, has received attention as a potential candidate for solar absorber, but it is still under-developed due to insufficient conversion efficiency. Fabricating SnS nanostructured films for solar cell design could be effective to boost photovoltaic performance and pave the way for applications in photovoltaics. Herein, a facile surfactant-free solution-based approach has been developed to prepare monolithic SnS nanostructured films directly on tin foil substrate. The morphologies of nanostructured films could be tuned from well-defined orthorhombic SnS nanobelt arrays to nanorods, nanosheets, or nanoflakes by simply changing the ratio of used solvents. The photoelectric response and electronic transportation properties of SnS nanobelts were investigated by fabricating single-nanobelt-based nanodevices. The SnS nanobelt exhibited a fast and reliable photoresponse even at illumination intensity as weak as 0.103 mW cm(-2). The measurements on SnS FET devices also indicated that the synthesized SnS nanobelts demonstrated a hole mobility as high as 12.33 cm(2) V(-1) s(-1). These results reveal that the reported approach for preparing monolithic SnS nanostructured films could be useful to further develop SnS as an alternative material for low-cost solar cells and electronic devices.

4.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 22(3): 156-60, 2010 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-20367906

RESUMO

OBJECTIVE: To investigate the clinical feature, treatment and outcome of respiratory failure in patients with 2009 influenza A H1N1 infection in critically ill adults. METHODS: A prospective observational study of 18 patients with respiratory failure suffering from 2009 influenza A H1N1 infection admitted between November 22, 2009 and January 16, 2010. Their clinical data were analyzed. RESULTS: Respiratory failure occurred in 18 patients with confirmed (n=9) or probable (n=9) 2009 influenza A H1N1. Among the 18 patients 8 patients were male, 10 patients were female (7 were pregnant or postpartum). Eight patients had pre-existing medical conditions. Twelve patients were between 20 and 40 years of age, the mean age was 37.1 years. Three were obese with body mass index over 30 kg/m (2). The 28-day mortality was 33.3% (6/18) with 1 additional late death. The median duration from the onset of the illness to hospital admission was 4.1 days (1-5 days) and from the onset to first dose of oseltamivir was 5.5 days (2-12 days), from onset to mechanical ventilation initiation was 6.8 days (4-12 days). Seventeen patients had primary viral pneumonia and 1 patient had an asthma exacerbation and 3 patients experienced multiple organ dysfunction syndrome (MODS). Twelve patients received corticosteroids, 10 patients required vasopressors. All patients were mechanically ventilated, 1 patient underwent extracorporeal membrane oxygenation (ECMO). Patients who died had higher acute physiology and chronic health evaluation II score compared to survivors (29.2 + or - 7.3 vs. 18.6 + or - 6.4, P=0.02). All deceased patients received high-level ventilation settings [peak inspiratory pressure > or = 35 cm H(2)O (1 cm H(2)O=0.098 kPa) and positive end-expiratory pressure > or = 18 cm H(2)O] within the first 7 days of ventilation, and the hypoxemia [oxygenation index < or = 60 mm Hg (1 mm Hg=0.133 kPa)] lasted 24 hours. In contrast only 1 among survivors did (9.1% vs. 100.0%, P<0.01). Compared with survivors, acute kidney injury and barotrauma occurred more frequently in non-survivors (42.9% vs. 27.3%, 28.6% vs. 9.1%, both P<0.05). Whereas all deceased patients received vasopressors, only 4 survivors required vasopressor support (100.0% vs. 36.4%, P<0.05). CONCLUSION: Severe acute respiratory distress syndrome is the most common manifestation in critically ill patients with 2009 influenza A H1N1 infection in adult. Failure to obtain satisfactory oxygenation with high-level ventilation settings within the first 7-days, onset of acute kidney injury and barotrauma, and continuous need for vasopressors portend a poor prognosis.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/complicações , Insuficiência Respiratória/terapia , Adulto , Oxigenação por Membrana Extracorpórea , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/etiologia , Prognóstico , Estudos Prospectivos , Respiração Artificial , Síndrome do Desconforto Respiratório do Adulto/etiologia , Insuficiência Respiratória/virologia , Adulto Jovem
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