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Layered double hydroxide nanoparticles (LDHNPs) with exceptionally small particle sizes are synthesized using a tripodal ligand of tris(hydroxymethyl)aminomethane (THAM). For example, a LDHNP with the average size of 9.7 nm (denoted as LDH(10 nm), containing CO 3 2− in the interlayer), can be synthesized using a 2.0 M THAM solution. The 13 C CP/MAS NMR and FTIR analyses show that THAM is ligated to the layer as an alkoxide species. The average particle size of LDH synthesized using L-lysine (buffering base) instead of THAM is larger (47.9 nm) than that of LDH(10 nm). Therefore, the size reduction is possibly explained by the specific interaction of THAM with the layer via its multiple coordination. In addition, it is confirmed by the 13 C CP/MAS NMR analysis that LDH(10 nm) possesses CO 3 2− species weakly interacting with the layers. LDHNPs, in particular, as-synthesized LDH(10 nm) (denoted as LDH(10 nm)-as, containing CO 3 2− and Cl − in the interlayer), possesses the extremely high anion exchange abilities, and almost all anions in LDH(10 nm)-as are potentially exchangeable with NO 3 − , even under ambient (CO 2 -existing) conditions. Furthermore, LDH(10 nm)-as can act as an efficient reusable scavenger for harmful oxyanions and remove arsenic, selenium, and boron from their dilute aqueous solutions under ambient conditions.

In the presence of Mo6+-doped α-MnO2 (Mo–MnO2), various sulfides could efficiently be oxidized to the corresponding sulfoxides as the major products. In addition, Mo–MnO2 could repeatedly be reused.

As an alternative to correlation-based techniques widely used in conventional speckle metrology, we propose a new technique that makes use of phase singularities in the complex analytic signal of a speckle pattern as indicators of local speckle displacements. The complex analytic signal is generated by vortex filtering the speckle pattern. Experimental results are presented that demonstrate the validity and the performance of the proposed optical vortex metrology with nano-scale resolution.

Recently, atomic ensemble and single photons were successfully entangled by using collective enhancement [D. N. Matsukevich, et al., Phys. Rev. Lett. 95, 040405(2005).], where atomic internal states and photonic polarization states were correlated in nonlocal manner. Here we experimentally clarified that in an ensemble of atoms and a photon system, there also exists an entanglement concerned with spatial degrees of freedom. Generation of higher-dimensional entanglement between remote atomic ensemble and an application to condensed matter physics are also discussed.

Three-dimensional entanglement of orbital angular momentum states of an atomic qutrit and a single photon qutrit has been observed. Their full state was reconstructed using quantum state tomography. The fidelity to the maximally entangled state of Schmidt rank 3 exceeds the threshold 2/3. This result confirms that the density matrix cannot be decomposed into an ensemble of pure states of Schmidt rank 1 or 2. That is, the Schmidt number of the density matrix must be equal to or greater than 3.

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Organic−inorganic lead halide perovskites are promising materials for realization of low-cost and high-efficiency solar cells. Because of the toxicity of lead, Sn-based perovskite materials have been developed as alternatives to enable fabrication of Pb-free perovskite solar cells. However, the solar cell performance of Sn-based perovskite solar cells (Sn-PSCs) remains poor because of their large open-circuit voltage (V OC ) loss. Sn-based perovskite materials have lower electron affinities than Pb-based perovskite materials, which result in larger conduction band offset (CBO) values at the interface between the Snbased perovskite and a conventional electron transport layer (ETL) material such as TiO 2 . Herein, the relationship between the V OC and the CBO in these devices was studied to improve the solar cell performances of Sn-PSCs. It was found that the band offset at the ETL/ perovskite layer interface affects the V OC of the Sn-PSCs significantly but does not affect that of the Pb-PSCs because the Sn-based perovskite material is a p-type semiconductor, unlike the Pb-based perovskite. It was also found that Nb 2 O 5 has the CBO that is closest to zero for Sn-based perovskite materials, and the V OC values of Sn-PSCs that use Nb 2 O 5 as their ETL are higher than those of Sn-PSCs using TiO 2 or SnO 2 ETLs. This study indicates that control of the energy alignment at the ETL/perovskite layer interface is an important factor in improving the V OC values of Sn-PSCs.