The Journal of Physical Chemistry Letters最新文献

With the advancement of information technology in contemporary society, there is an increasing demand for the rapid processing of large amounts of data. Concurrently, traditional silicon-based integrated circuits have reached their performance limits due to the exacerbation of non-ideal effects. This necessitates further multifunctionalities and miniaturization of modern integrated circuits. In recent years, two-dimensional (2D) materials have demonstrated exceptional physical and electrical properties and have emerged as a promising method for the development of next-generation electronic devices. Ferroelectric materials enable the flexible adjustment of polarization states, thereby simultaneously achieving non-volatile memory and the modulation of carrier transport. Moreover, reconfigurable logic allows for the dynamic adjustment of computational functions when different tasks are executed, significantly enhancing logical operation capabilities. Here, we report a reconfigurable logic inverter based on ferroelectric-gating MoS₂ field-effect transistors. Notably, the ferroelectric transistor achieves a high I_on/I_off ratio of ∼10⁶ and a memory window of ∼20 V. Furthermore, the reconfigurable inverter realized using two as-fabricated ferroelectric field-effect transistors (FeFETs) can produce three distinct output logics (including always "0", always "1", and inverter) in different polarization states under the same input. This study provides a strategy for achieving reconfigurable logic in ferroelectric-gating transistors, thereby offering a potential functional block for the development of in-memory computing.

Platinum is among the rarest elements on the planet, and the understanding of its formation and transport through aqueous fluids in the Earth, at high pressure and temperature, may help in the identification of new deposits. While complexation of platinum with sulfides, chlorides, and hydroxyl has been the topic of numerous investigations, the interaction of Pt and carbonates in aqueous fluids under pressure remains largely unexplored. Here, we present extensive first-principles molecular simulations of Pt (bi)carbonates at conditions (1 GPa, 1000 K and 11 GPa, 1000 K) relevant to the Earth crust and upper mantle and we predict how the metal speciation varies as a function of pressure and how it depends on its oxidation state. Furthermore, we compute Raman spectra and identify vibrational signatures that may be used to characterize the varied species in solutions. Our simulations provide valuable inputs to the Deep Earth Water model.

The competition between bulk and interfacial phenomena underlies many key processes in complex chemical phenomena and transport. While competitive processes are often framed in a thermodynamic context, opportunities to leverage transient species found away from equilibrium can provide a kinetic handle to achieve unconventional reaction outcomes. In this work, we outfit an iminoguanidinium headgroup capable of selective SO₄^2- complexation with alkyl tails of varying complexity to probe competitive bulk and interfacial reaction pathways and tune kinetic pathways for selective chemical separations. Using sum frequency generation (SFG) vibrational spectroscopy we unexpectedly find that adsorption of ligands to the air-aqueous interface was dramatically slowed down for species with increasingly hydrophobic tails. Underlying this phenomenon, we show that the formation of bulk colloidal species with differing propensities for SO₄^2- inhibited surface adsorption via a kinetic bottleneck in the exchange of molecular extractants with colloidal aggregates. This kinetic effect could open up avenues to access unconventional selectivity via complexation of strongly coordinating species in the bulk phase, allowing for more weakly coordinating species to transport via interfacial mechanisms. This work broadly probes nonequilibrium phenomena in chemical separations that arise through unexpected interfacial events that are neglected in traditional equilibrium descriptions.

Two-dimensional (2D) materials with tunable interlayer interactions hold immense potential for optoelectronic and photocatalytic applications. Understanding the dependence of carrier dynamics on twist angle in Janus bilayers is essential, as it directly impacts device efficiency. This study employs time-dependent density functional theory (TD-DFT) and nonadiabatic molecular dynamics (NAMD) to investigate twist-angle-dependent carrier dynamics in Janus MoSSe bilayers with type-II band alignment. Simulations reveal ultrafast charge transfer times of approximately 70 and 500 fs, largely independent of the twist angle due to multiple intermediate states. In contrast, the electron-hole recombination times depend strongly on twist angles, extending up to 133 ns for twisted configurations (21.8° and 38.2°) compared to 57 ns in high-symmetry bilayers (0.0° and 60.0°). Structural randomness in twisted bilayers weakens interlayer interactions, reducing nonadiabatic coupling and coherence time, which collectively prolong carrier lifetimes. These findings offer valuable guidance for designing 2D materials for high-efficiency photovoltaics and long-durable photocatalysts.

Conventional wisdom suggests that pristine graphene (Gr) is chemically inactive and that doping is an effective strategy to enhance its catalytic activity. Nevertheless, experimental evidence has demonstrated that non-metallic element (e.g., N, P, and S) doping of Gr significantly suppresses overall hydrogenation activity, yet the underlying mechanism remains to be elucidated. The present study investigates H₂ activation on P- and S-doped corrugated Gr using density functional theory calculations. The results show that the H₂ dissociation barriers on doped corrugated Gr are higher than those on undoped corrugated Gr, thus providing a plausible rationalization of the experimental observations. Importantly, the incorporation of non-metallic elements is found to exert a geometrical and electronic effect on Gr, signified by an increased distance and a decreased difference in the p_z band center between dissociation sites, which is deleterious to the stabilization of transition states in H₂ activation. This study provides theoretical insights for the design of efficient metal-free catalysts for hydrogenation via non-metallic doping engineering.

Intrinsic defects that serve as non-radiative recombination centers significantly accelerate charge and energy losses in hybrid organic-inorganic perovskites. The defect I_MA, formed by replacing an MA with an I in MAPbI₃ (MA = CH₃NH₃⁺), creates an I trimer that produces a deep electron trap state. Non-adiabatic (NA) molecular dynamics simulations demonstrate that an excited conduction band electron is rapidly captured by this electron trap within 100 ps, followed by recombination with a valence band hole within 1 ns, which is 3 times faster than that in the pristine system. Doping with interstitial Sr and Ba eliminates the electron trap state by breaking the I trimer, thereby restoring the electron-hole recombination across the bandgap to durations up to 3.20 and 4.36 ns, respectively. The delayed recombination is attributed to decreased NA coupling and a shortened decoherence time. These findings provide critical insights into perovskite defect passivation strategies with alkaline earth metals.

Intrinsic defects that serve as non-radiative recombination centers significantly accelerate charge and energy losses in hybrid organic–inorganic perovskites. The defect I_MA, formed by replacing an MA with an I in MAPbI₃ (MA = CH₃NH₃⁺), creates an I trimer that produces a deep electron trap state. Non-adiabatic (NA) molecular dynamics simulations demonstrate that an excited conduction band electron is rapidly captured by this electron trap within 100 ps, followed by recombination with a valence band hole within 1 ns, which is 3 times faster than that in the pristine system. Doping with interstitial Sr and Ba eliminates the electron trap state by breaking the I trimer, thereby restoring the electron–hole recombination across the bandgap to durations up to 3.20 and 4.36 ns, respectively. The delayed recombination is attributed to decreased NA coupling and a shortened decoherence time. These findings provide critical insights into perovskite defect passivation strategies with alkaline earth metals.

Constructing heterointerfaces with space charge areas can effectively drive carrier transport. However, it is difficult to further enhance the interfacial bond strength to improve the built-in potential difference across the interface by directly modulating the interfacial atomic configuration. Herein, we have directly regulated the atomic structures of ZnO/CoO heterointerfaces by means of the phase transition of the rocksalt CoO to spinel Co₃O₄ under a high-energy electron beam. The results show that irradiation of electron beams can drive the orderly migration and aggregation of Co vacancies as well as the rearrangement of lattice Co atoms from octahedral sites to tetrahedral sites, causing the formation of spinel Co₃O₄. DFT calculations demonstrate that O atoms adjected to four-coordinated Co atoms are strongly coupled with the Zn atoms, enhancing interfacial polarization to facilitate the charge transfer. This finding provides a novel idea for the design of heterojunctions with high-efficiency charge transport.

Cu is the most used substrate to grow monolayer graphene under a temperature near the melting point. In this study, we elaborated a remarkable amount of Cu clusters were continuously evaporated during the graphene growth, resulting in the vapor pressure comparable with the CH₄. Importantly, the decomposition barrier of CH₄ on Cu clusters is similar to or even lower than that on the Cu surface. CuCH₄ serves as the primary active cluster in complex intermediates, exhibiting a growth-promoting effect. Particularly after the first graphene layer coverage, it may emerge as a dominant catalytic factor for multilayer growth by supplying critical growth species. Through controlled seed incorporation, this mechanism is expected to enable large-area controllable growth of bilayer and multilayer graphene structures.

Organic semiconductor materials (OSMs) have emerged as innovative platforms for surface-enhanced Raman scattering (SERS). For now, SERS activity has been established in only a few materials like thiophene-based derivatives, and the potential of the broader OSM library is largely untapped. Systematic exploration of energy level alignment between analytes and the OSM substrates is highly desirable for further material screening and optimization. We introduce a strategy utilizing OSMs with the deep lowest unoccupied molecular orbital (LUMO) levels, exemplified by TCNQ and HATCN, as novel SERS active platforms realizing efficient detection of multiple organic dyes otherwise undetectable under low-energy incident laser irradiation at 785 nm. Our study showcases selective SERS enhancement for analytes with diverse highest occupied molecular orbital levels, highlighting the pivotal role of LUMO levels in both SERS activity and molecular sensitivity. This work elucidates the molecular structure-SERS activity correlation, facilitating the development of novel SERS substrates via the strategy of LUMO level tuning.