Polymer photovoltaic cells with power conversion efficiencies approaching 5 % have been fabricated using titanium oxide (TiOx) as an optical spacer (see Figure). Solar cells with a TiOx layer (deposited via a sol–gel process) between the active layer and the electron‐collecting aluminum electrode exhibit approximately a 50 % enhancement in short‐circuit current compared to similar devices without the optical spacer, as a result of modification of the spatial distribution of the light intensity inside the device.

The development of efficient and stable water oxidation catalysts is necessary for the realization of practically viable water-splitting systems. Although extensive studies have focused on the metal-oxide catalysts, the effect of metal coordination on the catalytic ability remains still elusive. Here we select four cobalt-based phosphate catalysts with various cobalt- and phosphate-group coordination as a platform to better understand the catalytic activity of cobalt-based materials. Although they exhibit various catalytic activities and stabilities during water oxidation, Na2CoP2O7 with distorted cobalt tetrahedral geometry shows high activity comparable to that of amorphous cobalt phosphate under neutral conditions, along with high structural stability. First-principles calculations suggest that the surface reorganization by the pyrophosphate ligand induces a highly distorted tetrahedral geometry, where water molecules can favourably bind, resulting in a low overpotential (∼0.42 eV). Our findings emphasize the importance of local cobalt coordination in the catalysis and suggest the possible effect of polyanions on the water oxidation chemistry.

The development of a water oxidation catalyst has been a demanding challenge in realizing water splitting systems. The asymmetric geometry and flexible ligation of the biological Mn4CaO5 cluster are important properties for the function of photosystem II, and these properties can be applied to the design of new inorganic water oxidation catalysts. We identified a new crystal structure, Mn3(PO4)2·3H2O, that precipitates spontaneously in aqueous solution at room temperature and demonstrated its high catalytic performance under neutral conditions. The bulky phosphate polyhedron induces a less-ordered Mn geometry in Mn3(PO4)2·3H2O. Computational analysis indicated that the structural flexibility in Mn3(PO4)2·3H2O could stabilize the Jahn-Teller-distorted Mn(III) and thus facilitate Mn(II) oxidation. This study provides valuable insights into the interplay between atomic structure and catalytic activity.

Despite promising expectations of technological impact, [1][2][3] electronic devices based on semiconducting [4,5] and metallic polymers [6] are not yet utilized in large scale commercial applications. The thin film form factor of polymer devices (thicknesses of approximately 100 nm) inevitably leads to vulnerability to the diffusion of oxygen and water vapor into the active layers. Moreover, most semiconducting polymer materials degrade when exposed to humidity and/or oxygen, and photo-oxidation can be a serious problem. [7][8][9] Here, we report an innovative approach that significantly extends the lifetime of polymer-based devices. By introducing a solution-based titanium oxide (TiO x ) layer between the active layer and the aluminum cathode in polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs), we have demonstrated devices with excellent air stability and with enhanced performance.The TiO x layer acts as a shielding and scavenging layer which prevents the intrusion of oxygen and humidity into the electronically active polymers, thereby improving the lifetime of unpackaged devices exposed to air by nearly two orders of magnitude. The degradation of polymer devices can be eliminated, or at least reduced to acceptable levels, by sealing the components inside an impermeable package using glass and/or metal. [10][11][12] Attempts to create flexible packaging using hybrid multilayer barriers comprised of inorganic oxide layers separated by polymer layers with total thickness of 5-7 lm have been reported with promising results. [13][14][15] Although such encapsulation methods can prevent (or at least reduce) oxygen and moisture permeation, they complicate the fabrication process, and also result in increased thickness and loss of flexibility. To achieve the goal of printed "plastic" electronics, either the development of improved barrier materials for packaging or the development of devices with reduced sensitivity (or both) are required. Thus, the creation of new methods for enhancing device lifetime is an important goal that must be accomplished without interfering with the principal 'flexible device' concepts; simple fabrication by solution processing, flexibility, and thin form factor. Since the pioneering research of Fujishima and Honda, [16] it is well known that titania (TiO 2 ) has a substantial oxygen/ water protection and scavenging effect originating from the combination of photocatalysis and inherent oxygen deficiency. [17][18][19] Therefore, the incorporation of TiO 2 into the polymer devices would seem to be a useful approach toward reducing the sensitivity of such devices to oxygen and water vapor. Typically, however, since crystalline TiO 2 layers can be prepared only at temperatures above 450°C, the formation of a protective layer in or on the device structure is not consistent with the fabrication of polymer electronic devices. By developing a solution-based sol-gel process that is consistent with and capable of fabricating a titanium sub-oxide (TiO x ) layer on top of the polymer...

Pharmacological studies suggest a role for CB1 cannabinoid receptors (CB1R) in regulating neurogenesis in the adult brain. To investigate this possibility, we measured neurogenesis by intraperitoneal injection of bromodeoxyuridine (BrdU), which labels newborn neurons, in wild-type and CB1R-knockout (CB1R-KO) mice. CB1R-KO mice showed reductions in the number of BrdU-labeled cells to ϳ50% of wild-type (WT) levels in dentate gyrus and subventricular zone (SVZ), suggesting that CB1R activation promotes neurogenesis. To test this further, WT mice were given the CB1R antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboximide hydrochloride (SR141716A) before measuring neurogenesis with BrdU.