Surface Metallization of Polyimide as a Photoanode Substratefor Rear-Illuminated Dye-Sensitized Solar Cells

Plastic film is promising as a photoanode substrate of dye-sensitized solar cell (DSSC) for flexible applications, while a lowtemperaturesintering process is generally adopted for the TiO2 mesoporous film due to unstable thermal property of general plastics.This study demonstrates that typical high-temperature TiO2 sintering can be adopted for preparing the photoanode when using asurface-metallized polyimide (PI) film. A Sn/Ni bi-layer is formed on a PI film via a chemical process as the conductive layer. TheSn/Ni-coated PI photoanode can withstand high-temperature TiO2 sintering at a peak temperature of 430◦C for 30 min withoutsignificant visual deformation due to high thermal stability of PI and strength reinforcement caused by surface metallization. TheDSSC employing the Sn/Ni-coated PI film as the photoanode substrate reaches an energy conversion efficiency of 3.44% under1 sun rear-side illumination

Roadmap on commercialization of metal halide perovskite photovoltaics

Perovskite solar cells (PSCs) represent one of the most promising emerging photovoltaic technologies due to their high power conversion efficiency. However, despite the huge progress made not only in terms of the efficiency achieved, but also fundamental understanding of the relevant physics of the devices and issues which affect their efficiency and stability, there are still unresolved problems and obstacles on the path toward commercialization of this promising technology. In this roadmap, we aim to provide a concise and up to date summary of outstanding issues and challenges, and the progress made toward addressing these issues. While the format of this article is not meant to be a comprehensive review of the topic, it provides a collection of the viewpoints of the experts in the field, which covers a broad range of topics related to PSC commercialization, including those relevant for manufacturing (scaling up, different types of devices), operation and stability (various factors), and environmental issues (in particular the use of lead). We hope that the article will provide a useful resource for researchers in the field and that it will facilitate discussions and move forward toward addressing the outstanding challenges in this fast-developing field

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Thermal Capacitive Electrochemical Cycle on Carbon-Based Supercapacitor for Converting Low-grade Heat to Electricity

It is a great challenge to efficiently convert low-grade heat (<100°C) to electricity. Currently available heat-to-current converters, such as thermoelectric generators, operating in a low-grade heat regime reach efficiencies no higher than a few percent (<3%). Herein, we illustrated a thermal capacitive electrochemical cycle (TCEC) using electrochemical cell, where the connection to the hot or cold reservoirs alternates in a cyclic charging–heating–discharging–cooling mode to convert heat into electricity, which performs as an electrochemical heat engine. TCEC technology is a cost-effective method for exploiting the temperature-dependent electrostatic potential in an electric double layer (EDL) at carbon electrode/electrolyte interfaces; it produces net electricity by altering the EDL thickness via heating and cooling. In this paper, TCEC on supercapacitor was confirmed on commercial supercapacitor, which showed a poor conversion efficiency. To improve the performance, we redesigned the cell by employing the pouch cell setup with activated carbon as electrode materials and homemade temperature controlling system, which boosted the efficiency from 0.5% of commercial supercapacitor to 3.05% when cycling between 10 and 65°C. A higher efficiency of 3.95% could be reached by using microwaved exfoliated graphene nanosheets (MEG) and nitric acid-treated MEG, which could help in decreasing the energy loss caused by charge leakage

Nickel substrate covered with a Sn-based protection bi-layer as aphotoanode substrate for dye-sensitized solar cells

Ni is a metallic substrate commonly used in microelectronic and opto-electronic devices due to its highstability, cost-efficiency and flexibility. Up to now, Ni has not yet been used as the substrate for thephotoanode in dye-sensitized solar cell (DSSC) because the formation of p-type Ni oxide hinders theelectron transfer from n-type TiO2mesoporous film to Ni substrate. In this paper, a Sn-based protectionbi-layer coating on the Ni foil successfully turns Ni into a good photoanode substrate in DSSC. A Sn layeris initially electroplated onto the Ni surface to prevent its oxidation. The Sn layer is then transformed intoa bi-layer of SnO2and Ni–Sn intermetallic compound after high-temperature TiO2sintering. Unlike thep-type Ni oxide layer, the top n-type SnO2layer enables the electron transfer from the TiO2mesoporousfilm to the conductive Ni substrate because its energy level of conduction band well matches that of TiO2.In addition, the interfacial Ni–Sn intermetallic compound is a good electrical conductor which facilitatesthe electron transfer. By carefully controlling the plating current density and time, a 1.2- m-thick Snlayer with a smooth surface morphology is formed and is recognized as the best protection layer over theNi substrate. The energy conversion efficiency of the resultant DSSC achieves 4.422% with a short-circuitcurrent density of 10 mA/cm2, an open-circuit voltage of 0.643 V, and fill factor of 0.689 under AM 1.5back-side illumination

Suppression of Void Formation at Sn/Cu Joint Due to Twin Formation in Cu Electrodeposit

The use of organic additives is crucial for Cu electrodeposition. However, specific impure species originating from the additives are incorporated in the Cu electroplated layer, causing serious reliability problems such as void formation at the solder/Cu joints. In this study, three Cu substrates were electroplated using various additive formulas. The use of organic additives results in an incorporation of a higher level of impurity in the Cu-electroplated layers and also affects the atomic deposition behavior of Cu which alters the grain microstructures. By using a specific additive formula, the grain growth of Cu evolves into a slender structure with a high density of twins. Thermal aging experiments of the Sn/Cu joints show that the void formation is successfully suppressed at the joint using a slender-grained Cu substrate, and that the suppression effect is attributed to the high microstructural stability of the twinning structure

Broadband Light Management with Thermochromic Hydrogel Microparticles for Smart Windows

© 2018 Intelligent control of solar irradiance through windows is promising to reduce building energy consumption by at least 1.055 × 10 15 kJ/year in the United States. Light management with thermochromic smart windows holds practical significance due to their autonomous system and simplicity of the device. However, the conventional thermochromic material (VO 2 ) faces scientific challenges with a high phase-transition temperature (68°C) and poor thermochromic performance. Temperature-responsive hydrogel emerges as a promising alternative, whereby light management could be pursued by maneuvering the light-scattering behaviors. This work reports the strategy to explore the thermochromic performance of co-polymerized hydrogel microparticles with the aid of tailoring particle size and internal structure. The solar modulation was effectively extended into the infrared region, and an unprecedented solar transmittance modulation of 81.3% was achieved at ∼32°C by our hydrogel thermochromic device with great scalability and stability