CVD graphene has attracted a great deal of interest from both academia and industry. The strong motivation to commercialize high quality CVD graphene films and related devices has been restricted by the lack of a cheap, efficient, clean and reliable graphene transfer process. In this article, we report a novel graphene transfer technique which provides a route to high-throughput, reliable and economical transfer of graphene without introducing large cracks and residue contamination from polymers, such as PMMA or magnetic impurities. The transferred graphene was thoroughly characterized with Raman spectroscopy, Atomic Force Microscopy, and X-ray photoelectron spectroscopy. Fabricated large area graphene-based field effect transistors exhibited high mobilities, which were about 2 times higher than those for devices prepared with graphene transferred by the conventional wet transfer method. This new graphene transfer technique has the potential to expedite M

Biological organisms naturally synthesize complex, hierarchical, multifunctional materials through mineralization processes at ambient conditions and under physiological pH. One such example is the ultrahard and wear‐resistant radular teeth found in mollusks, which are used to scape against the rock to feed on algae. Herein, the biologically controlled structural development of the hard, outer magnetite‐containing shell of the chitin teeth is revealed. Specifically, the formation of a series of mesocrystalline iron oxide phases, templated by chitin‐binding proteins, is identified. The initial domains, consisting of ferrihydrite mesocrystals with a spherulite‐like morphology, undergo a solid‐state phase transformation to form magnetite while maintaining mesocrystallinity, likely via a shear‐induced solid‐state reaction, without any noticeable architectural changes. Subsequent growth via Ostwald ripening leads to nearly single‐crystalline rod‐like elements. In addition, an interpenetrating organic matrix is identified that, at early stages of tooth development, potentially contains iron‐binding proteins that guide the self‐assembly of the mesocrystalline mineral and influence the preferred orientation of the later‐formed magnetite nanorods, which ultimately determines the mechanical behavior of the mature chiton teeth.

Improving the modulation depth and switching speed of electrochromic devices is important for expanding the field of electrochromic functional materials applications. The previous study demonstrates that semiconducting (SC‐) single‐wall carbon nanotube (SWNT) thin film based electrochromic cells with ionic liquid as the electrolyte and metallic (MT‐) SWNT counter electrode can operate with fast switching times in the millisecond range. However, achieving a high modulation depth requires an increasing thickness of the electrochromically active SC‐SWNT layer resulting in a slowdown of the switching time by more than order of magnitude. Here it is reported that milliseconds range switching time can be restored by increasing the thickness of MT‐SWNT thin film counter electrode thus matching the electrochemical capacitances of the two sides of the electrochromic cell while reaching a high modulation depth of 20 dB and high coloration efficiency exceeding 1800 cm2 C−1 at an infrared wavelength of 1770 nm. The results are interpreted in terms of considering the SWNT cell as a supercapacitor with two connected in series electric double layer 3D capacitors associated with two opposing SWNT electrodes.

Advances in the chemical vapor deposition (CVD) growth of graphene have made this material a very attractive candidate for a number of applications including transparent conductors, electronics, optoeletronics, biomedical devices and energy storage. The CVD method requires transfer of graphene on a desired substrate and this is most commonly accomplished with polymers. The removal of polymer carriers is achieved with organic solvents or thermal treatment which makes this approach inappropriate for application to plastic thin films such as polyethylene terephthalate substrates. An ultraclean graphene transfer method under mild conditions is highly desired. In this article, we report a naphthalene-assisted graphene transfer technique which provides a reliable route to residue-free transfer of graphene to both hard and flexible substrates. The quality of the transferred graphene was characterized with atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. Field effect transistors, based on the naphthalene-transfered graphene, were fabricated and characterized. This work has the potential to broaden the applications of CVD graphene in fields where ultraclean graphene and mild graphene transfer conditions are required.

In the present paper, the theoretical investigation of the device structure ITO/CeO2/SnS/Spiro-OMeTAD/Mo of SnS-based solar cell has been performed. The aim of this work is to examine how the Spiro-OMeTAD HTL affects the performance of SnS-based heterostructure solar cell. Using SCAPS-1D simulation software, various parameters of SnS-based solar cell such as work function, series and shunt resistance and working temperature have been investigated. With the help of Spiro-OMeTAD, the suggested cell’s open-circuit voltage was increased to 344 mV. The use of Spiro-OMeTAD HTL in the SnS-based solar cell resulted in 14% efficiency increase, and the proposed heterojunction solar cell has 25.65% efficiency. The cell’s performance is determined by the carrier density and width of the CeO2 ETL (electron transport layer), SnS absorber layer and Spiro-OMeTAD HTL (hole transport layer). These data reveal that the Spiro-OMeTAD solar cells could have been a good HTL (hole transport layer) in regards to producing SnS-based heterojunction solar cell with high efficiency and reduced cost.