No abstract

We report a facile roll-printing method, geometrically confined lateral crystal growth, for the fabrication of large-scale, single-crystal CH3NH3PbI3 perovskite thin films. Geometrically confined lateral crystal growth is based on transfer of a perovskite ink solution via a patterned rolling mould to a heated substrate, where the solution crystallizes instantly with the immediate evaporation of the solvent. The striking feature of this method is that the instant crystallization of the feeding solution under geometrical confinement leads to the unidirectional lateral growth of single-crystal perovskites. Here, we fabricated single-crystal perovskites in the form of a patterned thin film (3 × 3 inch) with a high carrier mobility of 45.64 cm2 V−1 s−1. We also used these single-crystal perovskite thin films to construct solar cells with a lateral configuration. Their active-area power conversion efficiency shows a highest value of 4.83%, which exceeds the literature efficiency values of lateral perovskite solar cells.

The nanoscale encapsulation of ferromagnetic structures has received a great deal of attention because of the exciting possibilities to use these materials in various applications that range from novel electromagnetic [1] to biomedical devices. [2,3] For example, nanoscale magnetic entities could be transported and concentrated at pretargeted locations or organs within the human body by means of an external magnetic field in order to exert a specific function with high local and temporal precision. Therefore, functionalized magnetic nanodots, nanowires, or nanotubes have a high potential for in vivo applications such as magnetic resonance imaging [4,5] or siteselective drug delivery systems, [2,3] if the magnetic property is combined with an appropriate drug loading and release mechanism.TiO 2 nanotubes are a highly promising encapsulating material for a magnetic core as a high degree of biocompatibility [6] can be combined with a broad range of other functionalities. Since the pioneering work of Fujishima and Honda in 1971, [7] it has been established that TiO 2 is a highly active photocatalyst; this is based on the ability of TiO 2 to produce electron-hole pairs upon light irradiation and thereby create highly reactive radical species. [8][9][10][11][12][13] This property of TiO 2 has been intensively explored in the form of photoelectrodes for the decomposition of various organic pollutants in water [14][15][16] and air, [17][18][19] and it has been used in self-cleaning, [20][21][22] disinfecting, [23,24] and anticancer [24,25] materials. The photocatalytic ability of TiO 2 can be enhanced by using nanosized TiO 2 materials because of their large specific surface area. Herein, we describe a simple way of embedding magnetic properties into TiO 2 nanotubes and demonstrate their different site-selective photocatalytic applications. Not only can these tubes be used as a magnetically guided photocatalyst for the decomposition of organic matter but also the photocatalytic mechanism can be exploited to release an active species (a model drug). Among the various synthetic routes used to prepare TiO 2 nanotubes, [26][27][28] anodization approaches have gained significant attention [29,30] as they lead to highly ordered nanotubular arrangements. During the past few years, our research group has contributed several generations of anodically grown self-organized TiO 2 nanotube layers by anodization of Ti in aqueous [31][32][33] and organic electrolytes. [34][35][36][37] In our approach, we use nanotube layers (Figure 1 a) that were produced in ethylene glycol/NH 4 F electrolytes [36][37][38] (see Section S1 and Figure S1 in the Supporting Information). These TiO 2 nanotubes were filled with magnetic nanoparticles by sucking a droplet of ferrofluid placed on the top of the nanotube layer using a permanent magnet (see the Supporting Information). Figure 1 b shows top-and side-view SEM images of the nanotubes that are loaded with the magnetic nanoparticles. It is clear from these images that the majority of the inside tube ...

No abstract

In the present study, a thin layer of Cu-based metal–organic frameworks (MOFs, copper(II) benzene-1,3,5-tricarboxylate) is fabricated using a layer-by-layer technique, and the layer is investigated as a light-absorbing layer in TiO2-based solar cells. Iodine doping of the MOFs is performed to improve the conductivity and charge-transfer reaction across the TiO2/MOF/electrolyte interface. The HOMO and LUMO energy states of the MOF films are estimated to be −5.37 and −3.82 eV (vs vacuum), respectively, which show a well-matched energy cascade with TiO2. For the first time, a TiO2-based solar cell is fabricated successfully using iodine-doped Cu-MOFs as an active layer, demonstrating a cell performance with J sc = 1.25 mA cm–2 and Eff = 0.26% under illumination of 1 sun radiation. In contrast, the cell with an undoped MOF layer exhibited J sc = 0.05 mA cm–2 and Eff = 0.008%. Electrochemical impedance spectroscopy of the cells suggests that iodine doping significantly reduces the charge-transfer resistance.

No abstract

A scalable and economical drop-cast aided approach for the synthesis of a self-supportive thin-film of Cu–Fe–NH2 based MOF nanosheets as a highly efficient and durable electrocatalyst for water-splitting at high currents.

An efficient and sustainable gas diffusible OER anode toward industrial alkaline water-splitting is fabricated by simply immersing Ni foam in ethanolic FeCl3 etchant, which produces a microporous Ni backbone decorated with nanocatalysts.