In replicate series of experiments in natural seawater, one in full darkness and the other in a 1:1 diurnal cycle with as little as ~5% of natural solar illumination, sunlight promoted calcareous deposition on cathodic stainless steel surfaces. As exemplified by scanning electron microscopy, the deposit that formed under the natural diurnal cycle, in the presence of photosynthetic biofilms, was composed of finer calcareous crystals that provided more compact and more uniform surface coverage than the one formed in the dark. The light-enhanced deposit also possessed better scale properties, as suggested by X-ray analysis and electrochemical measurements. Sunlight enhancement of calcareous deposition looked all the more conspicuous when day and night regimes were examined independently. These results not only bear important implications for cathodic protection in marine waters, but also provide an intriguing analogy to coral reef calcification.

Herein, organic-free all-solid-state based perovskite solar cells (PSCs) are successfully fabricated by one-step method. The absorption position of the non-perovskite cesium lead iodide (δ-CsPbI 3) was significantly shifted towards longer wavelength side by substituting indium (In) ion with different stoichiometric ratio. The authors demonstrated a facile route to achieve high efficiency by the fabrication of room temperature stable mixed-phase CsPbI 3 perovskite. Photovoltaic efficiency of doped perovskite is four times increased compared to pure yellow phase CsPbI 3. To the best of the authors' knowledge, this is the first demonstration of In-doped-CsPbI 3 based PSCs, which was fabricated under completely open-air atmosphere.

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