Fabricating complex transition metal oxides with a tunable bandgap without compromising their intriguing physical properties is a longstanding challenge. Here we examine the layered ferroelectric bismuth titanate and demonstrate that, by site-specific substitution with the mott insulator lanthanum cobaltite, its bandgap can be narrowed by as much as 1 eV, while remaining strongly ferroelectric. We find that when a specific site in the host material is preferentially substituted, a split-off state responsible for the bandgap reduction is created just below the conduction band of bismuth titanate. This provides a route for controlling the bandgap in complex oxides for use in emerging oxide optoelectronic and energy applications.

Triple perovskite, Nd1.5Ba1.5CoFeMnO9−δ, enriched with oxygen defects shows high activity and durability as a bifunctional oxygen electrocatalyst.

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A prospective, non-blinded, non-randomized study on 120 wart patients treated with pulsed dye laser was performed to evaluate the efficacy and safety of pulsed dye laser treatment for viral warts and to demonstrate the proper application and effective technique of this method. The overall clearance rate was 49.5%. The clearance rates of flat warts, periungual warts, plantar warts and common warts were 67.6%, 51.1%, 47.6% and 44.3%, respectively. Overall, the response rates of pediatric warts, recalcitrant warts and old warts were superior to those of adult warts, simple warts and non-old warts, respectively; however, those trends were not statistically significant. We concluded that pulsed dye laser treatment is a safe, tolerable and relatively effective treatment method for viral warts. Pulsed dye laser treatment may be a more efficacious method for flat warts and recalcitrant periungual warts, and it can be an effective modality for newly-developed warts. The highest clearance rate was noted at a fluence of 9.5 J/cm2 (P < or = 0.05) and it is recommended that practitioners perform pulsed dye laser treatments for viral warts at the fluences of 9.0-9.5 J/cm2. A replacement of pulsed dye laser treatment should be considered unless prominent improvement is observed after three treatment sessions.

2Transition metal oxides have been extensively studied and utilized as efficient catalysts. However, the strongly correlated behavior which often results in intriguing emergent phenomena in these materials has been mostly overlooked in understanding the electrochemical activities. Here, we demonstrate a close correlation between the phase transitions and oxygen evolution reaction (OER) in a strongly correlated SrRuO3. By systematically introducing Ru-O vacancies into the singlecrystalline SrRuO3 epitaxial thin films, we induced phase transition in crystalline symmetry which resulted in corresponding modification in the electronic structure. The modified electronic structure significantly affect the electrochemical activities, so a 30% decrease in the overpotential for the OER activity was achieved. Our study suggests that a substantial enhancement in the OER activity can be realized even within single material systems, by rational design and engineering of their crystal and electronic structures. 3Transition metal oxides show promising chemical activities that can be applied in solid oxide fuel cells (SOFC), rechargeable batteries, catalytic converters, oxygen-separation membranes, and gas sensors. [1][2][3][4][5] Oxygen evolution reaction (OER, 4OH -→ O 2 + 2H 2 O + 4e -) is one of the most important steps in energy conversion and storage mechanisms, and is the efficiency-limiting process in electrolytic water splitting and metal-air batteries. 6,7 The ultimate goal of OER study is to develop low-cost, highly active, and stable catalysts. 8,9 Recently, perovskite oxides (ABO 3 ), such as Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ , Pr 0.5 Ba 0.5 CoO 3-δ , and LaCoO 3 , have attracted much attention owing to their intrinsically high OER activity. [10][11][12] More interestingly, properties such as surface oxygen binding energy, number of outer shell electrons in the transition metal ion, electron occupancy of the e g orbitals, and the proximity of the oxygen p-band to the Fermi level, have been proposed as descriptors for OER activity. 10,11,13,14 Such approaches, however, have been mainly tested by comparing systems containing different transition metal elements.Unintentionally, such variations in the identity of the elements therein involve commensurate changes in the atomic structures, valence states, electric resistivities, crystalline surfaces, and the overall and specific electronic structures of the materials. Therefore, approaches based on simplified electronic structure may not apply to distinctive material systems, and more carefully controlled study, for example, one using a single-material system, is necessary to precisely understand the effect of the catalyst's electronic structure on the OER. 15In order to probe the link between electronic structure and catalytic activity within a singlematerial system, we exploit the strongly correlated behavior in complex oxides. In particular, the strong coupling among the degrees of freedom of the d-electrons, i.e., charge, spin, orbital, and lattice, in transition...