Deploying a Dipole Electric Field at the CsPbI3 Perovskite/Carbon Interface for Enhancing Hole Extraction and Photovoltaic Performance.

Carbon-based CsPbI3 perovskite solar cells without hole transporter (C-PSCs) have achieved intense attention due to its simple device structure and high chemical stability. However, the severe interface energy loss at the CsPbI3/carbon interface, attributed to the lower hole selectivity for inefficient charge separation, greatly limits device performance. Hence, dipole electric field (DEF) is deployed at the above interface to address the above issue by using a pole molecule, 4-trifluoromethyl-Phenylammonium iodide (CF3-PAI), in which the ─NH3 group anchors on the perovskite surface and the ─CF3 group extends away from it and connects with carbon electrode. The DEF is proven to align with the built-in electric field, that is pointing toward carbon electrode, which well enhances hole selectivity and charge separation at the interface. Besides, CF3-PAI molecules also serve as defect passivator for reducing trap state density, which further suppresses defect-induced non-radiative recombination. Consequently, the CsPbI3 C-PSCs achieve an excellent efficiency of 18.33% with a high VOC of 1.144 V for inorganic C-PSCs without hole transporter.

Spatially selective defect management of CsPbI3 films for high-performance carbon-based inorganic perovskite solar cells.

Defects formed at the surface, buried interface and grain boundaries (GB) of CsPbI3 perovskite films considerably limit photovoltaic performance. Such defects could be passivated effectively by the most prevalent post modification strategy without compromising the photoelectric properties of perovskite films, but it is still a great challenge to make this strategy comprehensive to different defects spatially distributed throughout the films. Herein, a spatially selective defect management (SSDM) strategy is developed to roundly passivate various defects at different locations within the perovskite film by a facile one-step treatment procedure using a piperazine-1,4-diium tetrafluoroborate (PZD(BF4)2) solution. The small-size PZD2+ cations could penetrate into the film interior and even make it all the way to the buried interface of CsPbI3 perovskite films, while the BF4- anions, with largely different properties from I- anions, mainly anchor on the film surface. Consequently, virtually all the defects at the surface, buried interface and grain boundaries of CsPbI3 perovskite films are effectively healed, leading to significantly improved film quality, enhanced phase stability, optimized energy level alignment and promoted carrier transport. With these films, the fabricated CsPbI3 PSCs based on carbon electrode (C-PSCs) achieve an efficiency of 18.27%, which is among the highest-reported values for inorganic C-PSCs, and stability of 500 h at 85 °C with 65% efficiency maintenance.

Electrodeposition of High-Quality Ni/SiC Composite Coatings by Using Binary Non-Ionic Surfactants.

In order to increase the hardness, wear resistance and corrosion resistance of nickel-based coatings, pure nickel is often co-electrodeposited with silicon carbide (SiC) particles. However, SiC particles tend to agglomerate and precipitate in the bath, which reduces the amounts of nanoparticles and causes nonuniformity. Herein, we solve these problems by using binary non-ionic surfactants (Span 80 and Tween 60) to effectively disperse SiC particles (binary-SiC) in the bath, which suppresses nanoparticles agglomeration and leads to uniformly distributed SiC particles in the composite coatings. In comparison to the Ni/SiC coatings electrodeposited from the commonly used SDS-modified SiC, the coatings prepared with binary-SiC (Ni/binary-SiC) show finer crystallization and a smoother surface. In addition, the Ni/binary-SiC coatings exhibit higher hardness (556 Hv) and wear resistance (2.95 mg cm-2). Furthermore, higher corrosion resistance is also achieved by the Ni/binary-SiC coatings.

Effects of Pre-Treatments on Bioactivity of High-Purity Titanium.

Titanium and its alloys are frequently employed in medical and dental clinics due to their good tissue compatibility, including commercially available pure Ti, Ti6A4V, or Ti-15Zr-4Ta-4Nb. Yet, they may behave very differently when in contact with our plasma because of their own chemical composition. The present study was designed to compare the in vitro behavior of highly pure Ti (>99.99%; hpTi) with those of the above titanium specimens when they were subjected to heating in air (HT), H2O2 and heating (CHT), and heating in air after forming grooves on the surface (GT). Since one of the measures of material-tissue compatibility has been in vitro apatite formation in artificial plasma, like simulated body fluid (SBF) of the Kokubo recipe, the apatite deposition in SBF on their surface and in their grooves were examined in terms of the X-ray diffraction, scanning electron microscopy, and energy dispersion X-ray analysis. The results showed that hpTi was as active in in vitro apatite deposition as the other reference titanium samples mentioned above. Moreover, GT specimens of hpTi induced apatite deposition on the platform of the grooves as well as in the grooves. Therefore, hpTi was concluded to have better activity, and to be clinically applicable.

A thermodynamic and kinetic study of trace iron removal from aqueous cobalt sulfate solutions using Monophos resin.

BACKGROUND: High purity cobalt has many important applications, such as magnetic recording media, magnetic recording heads, optoelectronic devices, magnetic sensors, and integrated circuits, etc. To produce 5N or higher purity cobalt in an electro-refining process, one of the challenges is to effectively reduce the Fe content of aqueous cobalt salt solution before electrolysis. This paper describes thermodynamic and kinetic investigations of the Fe adsorption process of a new sulfonated monophosphonic resin with the trade mark Monophos. METHODS: Five cobalt sulfate solutions of different Co concentrations were prepared. Fe ions were removed from the solutions by ion exchange method using Monophos resin. Chemical analysis was carried out using a Perkin Elmer ICP-OES. RESULTS: The initial Fe concentrations of about 0.9-2.0 mg/L can be reduced to about 0.3-0.8 mg/L, which is equivalent to an Fe removal rate of 60-67%. The Langmuir isothermal adsorption model applies well to the Fe removal process. A second-order type based on McKay equation fits better with experimental data than other kinetic models. The kinetic curve can be divided into two sections. For t < 30 min, particle diffusion may act as the controlling step, whereas chemical reaction may control the Fe adsorption process in the section t > 30 min. CONCLUSIONS: Monophos resin is effective for the removal of trace Fe from cobalt sulfate solution. This ion exchange process obeys the Langmuir isothermal adsorption model and the McKay equation of second-order kinetics.