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The chemical modulation associated with moiré patterns, arising at the interface of metal-supported 2D material systems, affects the interaction between molecules and 2D materials on surfaces. Since the crystallography of the support influences the interfacial chemistry of the moiré modulation, this parameter could also play a role in the graphene-molecule interaction, although studies using non-hexagonal metal supports are needed to investigate this effect. It is a key issue since graphene appears combined with organic films in most technological advances related to this material. Here, we have characterized the properties of PTCDA molecules on graphene grown on Rh(110) substrates, which exhibit a rectangular atomic packing, using scanning tunneling microscopy and spectroscopy. The results showed that PTCDA molecules are arranged on the surface into a herringbone structure exhibiting a long-range ordering, which grows continuously across substrate atomic steps edge and dislocations. The quasi-1D moiré patterns of the Gr/Rh(110) surfaces are found to provide an inert chemical landscape for the molecular arrangement. Bias voltage-dependent imaging of the orbital structure of PTCDA molecules and differential conductance spectra back up a weak molecule–substrate interaction scheme. Finally, the α-polymorph of bulk crystal PTCDA has been determined as the favored stacking configuration for bilayer molecules on Gr/Rh(110), Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) under grant No. MAT2016-77852-C2-2-R, as well as, from the Spanish Ministerio de Ciencia e Innovacion ´ (MICINN) through the “María de Maetzu” program for units of excellence in R&D (grant No. CEX2018-000805-M) is gratefully acknowledged. A. J. M.-G. acknowledges funding by the Spanish Ministerio de Ciencia e Innovacion ´ (MICINN) through Project No. PID2020-116619GA-C22, as well as, from the Comunidad de Madrid and the Universidad Autonoma ´ de Madrid under project SI3/PJI/2021- 00500

Thermoelectric devices based on thermoelectric materials, which can be utilized to transform heat to electric energy, are regarded as the clean and reliable energy-harvestings that reduce greenhouse gas and noxious gas missions. In this work, thermoelectric properties of square-Ag2X (X = S, Se) monolayers have been systematically studied through uniting Boltzmann transport theory and first-principles. The results show that square-Ag2X (X = S, Se) monolayers possess ultrahigh electrical conductivities due to their ultralight electron effective masses, together with high Seebeck coefficients, resulting in ultrahigh power factors (0.014 and 0.018 W/m K2). Moreover, phonon transport calculations unveil that square-Ag2X (X = S, Se) monolayers exhibit low lattice thermal conductivities (3.46 and 2.33 W/m K) at 300 K, which can be traced back to their small Debye temperature, low acoustic group velocities, short phonon relaxation times and large Gruneisen parameters. Accordingly, the obtained figure of merit of monolayer square-Ag2Se for optimal n-type doping at 700 K can approach 2.81, which is larger than the well-known n-type thermoelectric monolayer SnSe (2.32) and Mg3Sb2 (2.21). Therefore, the excellent thermoelectric properties of square-Ag2Se monolayer along with its all-round stability verified by the phonon dispersion, ab initio molecular dynamic simulation and accordance of Born–Huang criteria highlight its prominent potential for thermoelectric applications.

We theoretically explored the possibility of monolayer tellurene detecting nucleobases and amino acids by means of first-principles calculation. The obvious differences of adsorption energy between nucleobases indicate that monolayer tellurene can be used for DNA sequencing. The order of adsorption strength is G > A > C > T > U. Moreover, monolayer tellurene exhibits more excellent sensing performance to TYR, PHE and TRP than to HIS, which means that tellurene can be used for detecting amino acids. Besides, we explored the adsorption mechanism of nucleobases and amino acids on tellurene by ELF, which demonstrate nucleobases and amino acids are all physically adsorbed on tellurene. The calculated results of PDOS show that orbital hybridization is the primary cause of charge transfer between each biomolecule and monolayer tellurene. Furthermore, the results of absorption coefficient and refractive index further prove that tellurene can detect nucleobases and amino acids. Therefore, we conclude that monolayer tellurene can be a promising candidate for biosensor to detect nucleobases and amino acids.