First Principle Study of Salinity Measurement by 2D Material

By using first principle calculations, a simple model of salinity sensor based on graphene electrode is constructed and its electron transport property is systematically investigated. It is found that all saltwater clusters at different salinity exhibit an obvious increase of the current while the saltwater to be detected is passing through the device. Moreover, only changing one Na atom acted as the conductive medium, and the electron transport behaviors could be clearly distinguished among the saltwater by negative differential resistance phenomenon, which demonstrates that the graphene-based salinity sensor could be capable of distinguishing saltwater at different salinity efficiently and accurately. This study provides a new path for the creation of the novel salinity sensor by graphene and other 2D material electrode.

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

With the recent advance in chemical modification of fullerenes, electrosynthesis has demonstrated increasing importance in regioselective synthesis of novel fullerene derivatives. Herein, we report successively regioselective synthesis of stable tetra- and hexafunctionalized [60]fullerene derivatives. The cycloaddition reaction of the electrochemically generated dianions from [60]fulleroindolines with phthaloyl chloride regioselectively affords 1,2,4,17-functionalized [60]fullerene derivatives with two attached ketone groups and a unique addition pattern, where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is fused to an adjacent [6,6]-junction. This addition pattern is in sharp contrast with that of the previously reported biscycloadducts, where both cycles are appended to [6,6]-junctions. The obtained tetrafunctionalized compounds can be successively manipulated to 1,2,3,4,9,10-functionalized [60]fullerene derivatives with an intriguing “S”-shaped configuration via a novel electrochemical protonation. Importantly, the stability of tetrafunctionalized [60]fullerene products allows them to be applied in planar perovskite solar cells as efficient electron transport layers.

Effects of Surface Doping of Si Absorbers on the Band Alignment and Electrical Performance of TiO2-Based Electron-Selective Contacts

ABSTRACTWe have investigated the chemical and electrical properties of a thin SiO2/TiO2 stacking layer deposited on n-Si and heavily phosphorus-doped n++ Si substrates to elucidate effects of phosphorus doping of Si absorbers on the band alignment and electrical performance of a SiO2/TiO2 stack-based electron-selective contact deposited on the differently doped Si substrates. From our XPS study, we show a shift of the TiO2 energy levels up to ∼0.13 eV with respect to those of Si as the doping level of Si substrates changes. We also show that the conduction band offset of the SiO2/TiO2 stacking layer at the interface with the n++ Si substrate seems to smaller than that of the SiO2/TiO2 stacking layer at the interface with n-Si substrate. Finally, from our electrical transport measurements, we could conclude that the thinner tunneling barrier, the increased electron density in front of the SiO2 layer in the n++ Si surface, and/or the reduced barrier height by heavy doping, seem to enhance the majority electron transport property of the SiO2/TiO2/n++ Si samples compared to that of the SiO2/TiO2/n-Si samples.

High-performance inverted planar perovskite solar cells using a pristine fullerene mixture as an electron-transport layer

A mixture of C60/C70 can improve the solubility and maintain the original electron-transport property at the same time.

Nb and Ta layer doping effects on the interfacial energetics and electronic properties of LaAlO3/SrTiO3 heterostructure: first-principles analysis

Nb(Ta) layer doping at the interfacial region of the LaAlO3/SrTiO3 heterostructure system provides a possible avenue to tune the electron transport property of the two-dimensional electron gas.