A novel 3D calcium-based metal-organic framework based on a naphthalene diimide chromophore has been synthesized which displays a unique doubly interpenetrated 7-connected net with total point symbol of {3(6)·4(9)·5(6)}. Excellent thermal stability and reversible photochromic properties have been observed in this compound.

Nitrogen-doped titanium dioxide (TiO 2 /N) nanoparticle thin films have been produced by a sol-gel method with hexamethylenetetramine (HMT) as the dopant source. The synthesized TiO 2 /N thin films have been sensitized with CdSe quantum dots (QDs) via a linking molecule, thioglycolic acid (TGA). Optical, morphological, structural, and photocurrent properties of the thin films with and without QD sensitization have been characterized by AFM, TEM, XPS, Raman spectroscopy, UV-visible spectroscopy, and photoelectrochemistry techniques. AFM measurements reveals that films with thicknesses of 150 and 1100 nm can be readily prepared, with an average TiO 2 particle size of 100 nm. TEM shows a uniform size distribution of CdSe QDs utilized in sensitizing the TiO 2 /N films. Doping of the TiO 2 crystal lattice by HMT was confirmed to be 0.6-0.8% by XPS. Differences in crystal phase caused by the precursors HMT, nitric acid, and poly(ethylene glycol) (PEG) are elucidated using XRD and Raman spectroscopy. The resultant crystal phase of TiO 2 /N varies but is a mixture of anatase, brookite, and rutile phases. UV-visible absorption spectra show that N doping of TiO 2 causes a red-shifted absorption into the visible region, with an onset around 600 nm. Nitrogen doping is also responsible for the enhanced photocurrent response of the TiO 2 /N nanoparticle films in the visible region relative to undoped TiO 2 films. In addition, CdSe QDs linked to TiO 2 /N nanoparticles using TGA were found to significantly increase the photocurrent and power conversion of the films compared to standard TiO 2 /N films without QD sensitization. The incident photon-to-current conversion efficiency (IPCE) is 6% at 400 nm for TiO 2 /N-TGA-CdSe solid-state solar cells and 95% for TiO 2 /N-TGA-CdSe films near 300 nm in a Na 2 S electrolyte, which is much higher than that of undoped TiO 2 with QD sensitization or TiO 2 /N without QD sensitization. The power conversion efficiency (η) was found to be 0.84% with a fill factor (FF%) of 27.7% with 1100 nm thick TiO 2 /N-TGA-CdSe thin films. The results show that combining nitrogen doping with the QD sensitization of TiO 2 thin films is an effective and promising way to enhance the photoresponse in the near-UV and visible region, which is important for potential photovoltaic (PV) and photoelectrochemical applications.

Room-temperature ferromagnetism in (Mn, N)-codoped TiO 2 films grown by plasma assisted molecular beam epitaxy J. Appl. Phys.

The oceans represent a significant sink for atmospheric CO 2 , acting as the largest pool of exchangeable carbon in the world. Globally, approximately 39,000 GtC of total carbon is stored in the ocean, up to 95% of which is in the form of dissolved inorganic carbon (DIC; Key et al., 2004;Schuur et al., 2016). Each year, approximately 30%-40% of anthropogenically produced CO 2 is absorbed by the ocean through air-sea exchange and dissolved as DIC in the ocean (Gruber et al., 2009;Lemke et al., 2007). The variability in DIC in the ocean is controlled not only by air-sea exchange (Tsunogai, 2000;Winn et al., 1998) but also by changes in ocean circulation and biological activities (Gruber, 2011;Tsurushima et al., 2002;Wakita et al., 2010). The distribution and cycling of DIC in the ocean therefore play crucial roles in the global carbon cycle and in climate change (Key et al., 2004;Valsala et al., 2012;Yasunaka et al., 2014).Radiocarbon ( 14 C) natural abundances have been used in studies of marine carbon cycling to determine the sources, residence times, transformations, and interactions of both organic and inorganic carbon reservoirs (Bau-