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The pentagonal boron carbon nitride (penta-BCN) monolayer has been recently proposed as a new member of the pentagon-based two-dimensional nanosheets [Zhao et al., J. Phys. Chem. Lett. 11(9), 3501 (2020)]. By using density functional theory with the generalized gradient approximation, we have carried out detailed investigations of a hydrogenated penta-BCN sheet, where the pristine penta sheet is decorated with H atoms to the composition BCNH2. The hydrogenated penta-BCN (H-BCN) structure is mechanically, thermally, and dynamically stable. It has a wide and indirect bandgap of 4.46 eV, contrasting with the direct gap of 1.70 eV in pristine BCN. H-BCN is environmentally stable at 1 bar of H2 down to 10−10 bar; beyond this point, pristine BCN becomes more stable. Compared with penta-BCN, the components of the elastic modulus tensor C 11 and C 12 of hydrogenated penta-BCN are reduced, while C 12 and C 66 are increased. The strain tensors of piezoelectricity in H-BCN are d 21 = 0.462 , d 22 = 0.213 , and d 16 = 1.03 pm / V , which are lower than those of pristine penta-BCN. The hydrogenated BCN structure displays a higher spontaneous polarization Ps than penta-BCN (4.64 × 10−10 vs 3.38 × 10−10 C/m, respectively). The smaller in-plane Young's moduli E a and E b for H-BCN indicated that that they are softer than those for penta-BCN. Strain engineering can help tune electronic properties. In agreement with this claim, we found that the indirect gap of H-BCN was tunable from 4.46 to 3.26 eV under an applied tensile strain of 0%–16%, the range where the structure is dynamically stable throughout. Meanwhile, H-BCN is dynamically unstable under an applied compressive strain. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) pentagonal nanostructures have been caught research attention down to their electronic, optical, mechanical and thermal transport properties. Among them, the newly proposed ternary penta-BCN monolayer shows a great potential for piezoelectric materials according to intrinsic piezoelectricity and spontaneous polarization. Nevertheless, the effect of strain toward these properties of the penta-BCN has not been elucidated. In this study, using density-functional theory with the Perdew–Burke–Ernzerhof (PBE) functional, we have investigated the impact of a uniform biaxial strain on the electronic structure and the thermal conductivity of the semiconducting penta-BCN single sheet. The strain-free penta-BCN monolayer is mechanically and dynamically stable with an indirect band gap of 1.70 eV. The sheet is rather soft as judged from the low in-plane Young's moduli. The pentagonal structure is preserved up to the yielding point of 18.4%, beyond this point the irreversible transition into the dynamically unstable, honeycomb-like system is observed. In contrast, the penta-BCN has dynamically instability under the compressive strain as small as −4%. The PBE band gap of the penta-BCN monolayer could be tuned within a range of 1.36–1.70 eV, falling into the infrared spectrum. The calculated lattice thermal conductivity of penta-BCN is around 97 W m−1 K−1 at temperature of 300 K, and decreases with increasing temperature. [ABSTRACT FROM AUTHOR]

Solution‐processed copper(I) thiocyanate (CuSCN) typically exhibits low crystallinity with short‐range order; the defects result in a high density of trap states that limit the device's performance. Despite the extensive electronic applications of CuSCN, its defect properties are not understood in detail. Through X‐ray absorption spectroscopy, pristine CuSCN prepared from the standard diethyl sulfide‐based recipe is found to contain under‐coordinated Cu atoms, pointing to the presence of SCN− vacancies. A defect passivation strategy is introduced by adding solid I2 to the processing solution. At small concentrations, the iodine is found to exist as I− which can substitute for the missing SCN− ligand, effectively healing the defective sites and restoring the coordination around Cu. Computational study results also verify this point. Applying I2‐doped CuSCN as a p‐channel in thin‐film transistors shows that the hole mobility increases by more than five times at the optimal doping concentration of 0.5 mol.%. Importantly, the on/off current ratio and the subthreshold characteristics also improve as the I2 doping method leads to the defect‐healing effect while avoiding the creation of detrimental impurity states. An analysis of the capacitance‐voltage characteristics corroborates that the trap state density is reduced upon I2 addition. [ABSTRACT FROM AUTHOR]

Penta-PdPSe, a synthesizable material, holds great promise for the field of nano-scale piezoelectronics. In this work, we demonstrate that this non-piezoelectric material can be converted into a piezoelectric material through the simple incorporation of sulfur on its surface. The result of this transformation maintains the structural, dynamical, mechanical, and thermal stabilities. This breakthrough offers a new approach for the design and development of piezoelectric materials, leading to their wider application in areas such as energy harvesting, sensing, and actuator technology. With penta-PdPSe's synthesizability, we can now broaden the material selection for piezoelectronics. [Display omitted] • Theoretically proposed a method for inducing piezoelectricity in synthesizable non-piezoelectric penta-PdPSe material via a sulfur alloy. • Reported first-time discovery of three dynamically, mechanically, and thermally stable alloyed penta-PdPSeS configurations out of four. • Introduced piezoelectricity to pentagonal materials with visible bandgap, showing potential for optoelectronic nano-devices. [ABSTRACT FROM AUTHOR]

Hole Transports In article number 2209504, Pichaya Pattanasattayavong and co‐workers, report that X‐ray absorption spectroscopy reveals the incomplete coordination environment around Cu(I) centers in CuSCN which can be associated with SCN− vacancies acting as hole‐trapping states. Doping with an optimal amount of I2 leads to defect‐healing and a drastic improvement in hole transport. [ABSTRACT FROM AUTHOR]

Copper(I) thiocyanate, defect healing, doping, hole transports, thin-film transistors Origin of Hole-Trapping States in Solution-Processed Copper(I) Thiocyanate and Defect-Healing by I2 Doping (Adv. Funct. Keywords: copper(I) thiocyanate; defect healing; doping; hole transports; thin-film transistors EN copper(I) thiocyanate defect healing doping hole transports thin-film transistors 1 1 1 06/22/23 20230619 NES 230619 B Hole Transports b In article number 2209504, Pichaya Pattanasattayavong and co-workers, report that X-ray absorption spectroscopy reveals the incomplete coordination environment around Cu(I) centers in CuSCN which can be associated with SCN SP - sp vacancies acting as hole-trapping states. [Extracted from the article]