Controlling charge transport through molecular-scale devices is of crucial importance. This article reports an effective route to tailor cross-plane charge transport in a vertical molecular tunneling junction through controlled chemical or electrochemical redox reaction in the self-assembled molecular monolayers buried under graphene. This redox control of the cross-plane charge transport is important for exploring fundamental mechanisms and realizing new functionalities in molecular electronics.

The electronic transmission of fifteen potential configurations of single-phenanthrene junction has been theoretically investigated. The structures include para-para, para-meta, and meta-meta combined with phenyl pendant group and substituted nitrogen atom. The results show that the para-meta, which offers a tunable antiresonance in the HOMO-LUMO gap, is the most suitable for synthesizing nano-device. The antiresonance is susceptible (unsusceptible) to the heteromotif location at site four (five). Hence, our paper presents the appropriate hetero-motif conditionstype and location-to synthesize molecular devices with the desired electronic conductance. The study also deepen the understanding of the molecular conductance by demonstrating the active and inactive sites to create and tune antiresonances. It finally introduces the essential impact of connectivity, quantum interference, and aromaticity in controlling the conductance of singlephenanthrene junction.

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With the dawning of 21st century, governments faced three urgent challenges, global economic crisis, energy crisis and global warming. So, the research goals have directed on developing novel renewable-energy technologies as suitable alternative sources of the traditional energy that addresses these problems. Photovoltaic based solar cells technology gives sustainable solutions and depends on inorganic materials with specific properties. Among this family, halide perovskites (MBX3) have been investigated during the last five years. Besides studying their unique properties as flexible structures, high stability, tunable semiconductor band-gap (Eg < 2.50 eV), high charge-carrier mobility and large optical absorption, research also seek for promising and multifaceted electroptical applications that give an amazing power efficiency (~24.0 %) in photovoltaic technology. The current challenge is to synthesis MBX3 materials provide suitable properties, include notable chemical stability at high temperatures, high electrical power efficiency, broad emission and tunable semiconducting Eg. Motivated by the site substitution effect, we extended this concept to build a series of cesium-metalloid MBX3 (M1+ = Cs; B2+ = Si, Ge, Sn, Pb; X– = Cl, Br, I), and investigate their structural, stability and optoelectronic properties. We expect these investigations will provide inspiration for an innovation of such MBX3 materials in photovoltaic applications.

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