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The on-demand assembly of 2D heterostructures has brought about both novel interfacial physical chemistry and optoelectronic applications; however, existing studies rarely focus on the complementary part—the 2D cavity, which is a new-born area with unprecedented opportunities. In this study, we have investigated the electric field inside a spacer-free 2D cavity consisting of a monolayer semiconductor and a gold film substrate. We have directly captured the built-in electric field crossing a blinking 2D cavity using a Kelvin probe force microscopy–Raman system. The simultaneously recorded morphology (M), electric field (E), and optical spectroscopy (O) mapping profile unambiguously reveals dynamical fluctuations of the interfacial electric field under a constant cavity height. Moreover, we have also prepared non-blinking 2D cavities and analyzed the gap-dependent electric field evolution with a gradual heating procedure, which further enhances the maximum electric field exceeding 109 V/m. Our work has revealed substantial insights into the built-in electric field within a 2D cavity, which will benefit adventures in electric-field-dependent interfacial sciences and future applications of 2D chemical nanoreactors. [ABSTRACT FROM AUTHOR]

Localized excitation in traditional organic photocatalysts typically prevents the generation and extraction of photo‐induced free charge carriers, limiting their activity enhancement under illumination. Here, we enhance delocalized photoexcitation of small molecular photovoltaic catalysts by weakening their electron‐phonon coupling via rational fluoro‐substitution. The optimized 2FBP‐4F catalyst we develop here exhibits a minimized Huang–Rhys factor of 0.35 in solution, high dielectric constant and strong crystallization in the solid state. As a result, the energy barrier for exciton dissociation is decreased, and more importantly, polarons are unusually observed in 2FBP‐4F nanoparticles (NPs). With the increased hole transfer efficiency and prolonged charge carrier lifetime highly related to enhanced exciton delocalization, the PM6 : 2FBP‐4F heterojunction NPs at varied concentration exhibit much higher optimized photocatalytic activity (207.6–561.8 mmol h−1 g−1) for hydrogen evolution than the control PM6 : BP‐4F and PM6 : 2FBP‐6F NPs, as well as other reported photocatalysts under simulated solar light (AM 1.5G, 100 mW cm−2). [ABSTRACT FROM AUTHOR]

Localized excitation in traditional organic photocatalysts typically prevents the generation and extraction of photo‐induced free charge carriers, limiting their activity enhancement under illumination. Here, we enhance delocalized photoexcitation of small molecular photovoltaic catalysts by weakening their electron‐phonon coupling via rational fluoro‐substitution. The optimized 2FBP‐4F catalyst we develop here exhibits a minimized Huang–Rhys factor of 0.35 in solution, high dielectric constant and strong crystallization in the solid state. As a result, the energy barrier for exciton dissociation is decreased, and more importantly, polarons are unusually observed in 2FBP‐4F nanoparticles (NPs). With the increased hole transfer efficiency and prolonged charge carrier lifetime highly related to enhanced exciton delocalization, the PM6 : 2FBP‐4F heterojunction NPs at varied concentration exhibit much higher optimized photocatalytic activity (207.6–561.8 mmol h−1 g−1) for hydrogen evolution than the control PM6 : BP‐4F and PM6 : 2FBP‐6F NPs, as well as other reported photocatalysts under simulated solar light (AM 1.5G, 100 mW cm−2). [ABSTRACT FROM AUTHOR]

Colloidal semiconductor nanocrystals (NCs) have been recognized as promising solution-processable gain media; however, the lasers with state-of-the-art performance exclusively originate from the cadmium- and lead-based NCs. Herein, we for the first time unravel that high-quality heavy-metal-free ZnSe/ZnS NCs show superior optical gain and lasing performance when the sizes exceed the quantum confinement regime. Corroborated by comprehensive transient spectroscopy, we reveal that the optical gain in large ZnSe/ZnS NCs originates from the novel Coulomb-correlated electron–hole plasma (C-EHP) instead of high-order multi-exciton recombination. Thanks to the formation of a four-level system and the suppression of Auger recombination, the C-EHP renders low gain threshold (9.4 μJ/cm2), high gain coefficient (>6500 cm−1), and long gain lifetime (∼4 ns). Such desirable gain properties compete well with those of classic CdSe NCs and enable the construction of a high-performance laser device. This work represents significant progress toward the development of solution-processable non-heavy-metal nanocrystal lasers. [ABSTRACT FROM AUTHOR]

CO2 electroreduction (CO2R) operating in acidic media circumvents the problems of carbonate formation and CO2 crossover in neutral/alkaline electrolyzers. Alkali cations have been universally recognized as indispensable components for acidic CO2R, while they cause the inevitable issue of salt precipitation. It is therefore desirable to realize alkali‐cation‐free CO2R in pure acid. However, without alkali cations, stabilizing *CO2 intermediates by catalyst itself at the acidic interface poses as a challenge. Herein, we first demonstrate that a carbon nanotube‐supported molecularly dispersed cobalt phthalocyanine (CoPc@CNT) catalyst provides the Co single‐atom active site with energetically localized d states to strengthen the adsorbate‐surface interactions, which stabilizes *CO2 intermediates at the acidic interface (pH=1). As a result, we realize CO2 conversion to CO in pure acid with a faradaic efficiency of 60 % at pH=2 in flow cell. Furthermore, CO2 is successfully converted in cation exchanged membrane‐based electrode assembly with a faradaic efficiency of 73 %. For CoPc@CNT, acidic conditions also promote the intrinsic activity of CO2R compared to alkaline conditions, since the potential‐limiting step, *CO2 to *COOH, is pH‐dependent. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts and devices for acidic CO2R. [ABSTRACT FROM AUTHOR]

CO2 electroreduction (CO2R) operating in acidic media circumvents the problems of carbonate formation and CO2 crossover in neutral/alkaline electrolyzers. Alkali cations have been universally recognized as indispensable components for acidic CO2R, while they cause the inevitable issue of salt precipitation. It is therefore desirable to realize alkali‐cation‐free CO2R in pure acid. However, without alkali cations, stabilizing *CO2 intermediates by catalyst itself at the acidic interface poses as a challenge. Herein, we first demonstrate that a carbon nanotube‐supported molecularly dispersed cobalt phthalocyanine (CoPc@CNT) catalyst provides the Co single‐atom active site with energetically localized d states to strengthen the adsorbate‐surface interactions, which stabilizes *CO2 intermediates at the acidic interface (pH=1). As a result, we realize CO2 conversion to CO in pure acid with a faradaic efficiency of 60 % at pH=2 in flow cell. Furthermore, CO2 is successfully converted in cation exchanged membrane‐based electrode assembly with a faradaic efficiency of 73 %. For CoPc@CNT, acidic conditions also promote the intrinsic activity of CO2R compared to alkaline conditions, since the potential‐limiting step, *CO2 to *COOH, is pH‐dependent. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the designs of catalysts and devices for acidic CO2R. [ABSTRACT FROM AUTHOR]

Organic–inorganic tin (Sn)‐based halide perovskites have attracted special attention due to their outstanding photophysical properties and eco‐friendly nature. However, the instability of Sn‐based perovskites is still a pressing issue that needs to be addressed. Here, a new lead‐free hybrid Sn(IV) bromide hybrid (4‐APEA)2SnBr6 (4‐APEA: 2‐(4‐aminophenyl)ethylammonium) is synthesized with remarkable stability. This compound has strong electron–phonon coupling, resulting in excitons self‐trapping and broadband yellow emission with a photoluminescence peak at 566 nm. The bare (4‐APEA)2SnBr6 shows impressive emission stability in the air; maintains 90% of photoluminescence quantum yield under ultraviolet light irradiation over 2000 h (T90 > 2000 h), representing the most stable halide hybrids. The excellent stability is profit from the stable valence state and few defect state densities. The findings show the promising prospect of environment‐friendly organic–inorganic halide perovskites and their usage in optoelectronic applications. [ABSTRACT FROM AUTHOR]

Tailoring the photoluminescence (PL) of semiconductors through spatiotemporal manipulation of dynamics of photoexcited carriers is of paramount importance for understanding the emitting mechanism and developing high‐performance devices. Herein, fluorescence recovery after photobleaching (FRAP) microscopy, a powerful tool in biology, is first utilized to simultaneously manipulate and monitor the dynamics of photoexcited carrier in attractive 2D transition metal dichalcogenide monolayers (1L‐TMDs). This allows on‐demand access to the PL dark state of 1L‐TMDs, based on the triggered exciton–exciton annihilation by pump beam‐initiated photodoping. Using a 0.7‐µm‐diametered pump laser, the PL dark region can be facilely tailored from ≈0.5 to ≈5 µm over a 10‐µm‐1L‐WS2 flake. An interesting photoinduced dedoping effect in 1L‐TMDs after photodoping is discovered by FRAP, which has not been observed before and might account for the non‐blinking emission of 1L‐TMDs. The revealed mono‐exponential photo‐dedoping can also be kinetically tailored by ≈170‐fold (k: 0.11–19.00 s‐1) by humidity, power of incident laser and type of 1L‐TMDs. This study demonstrates the power of FRAP microscopy in exploring the effect of photoexcited carrier dynamics on the PL property of semiconductors, holding promises for understanding light‐emitting mechanism and optimizing operational parameters for optoelectronic devices. [ABSTRACT FROM AUTHOR]

This work reports a series of novel AAILs proposed via one-step hydrolysis of cheap lactams to act as messengers to facilitate aqueous solution of multi-tertiary-amines fast and pronounced absorption of CO 2. [Display omitted] • Novel AAILs were proposed via one-step hydrolysis of available cheap lactams. • AAILs facilitate multi-tertiary-amines solution fast absorption of CO 2. • The exceptional absorption capacity of CO 2 can reach 0.162 g·g−1 at 313.2 K. • The regeneration was evaluated by vacuum and dynamic thermal regeneration. • Apparent absorption rate constant was calculated by dynamic absorption experiment. Carbon capture, utilization, and storage (CCUS) are among the key technologies to achieve large-scale carbon emission reduction globally. Amino acid ionic liquids (AAILs) featuring biodegradability and biological activity are capable as eco-friendly absorbents for CO 2 capture. Herein, a series of novel AAILs are proposed via one-step hydrolysis of cheap lactams, which can act as messengers to facilitate aqueous solution of multi-tertiary-amines fast and pronounced absorption of CO 2. Dynamic absorption experiments were carried out to indicate that [N 1111 ][Maba]-PMDETA-50 % showed a larger apparent absorption rate constant (0.282 min−1) than that of MDEA solution (0.043 min−1), demonstrating the activated role of AAILs. [N 1111 ][Maba]-PMDETA-50 % shows the exceptional absorption capacity of 0.162 g (1.0 bar) or 0.095 g (0.1 bar) of CO 2 per g absorbent at 313.2 K, respectively, surpassing all the reported formulated solution. The facilitated absorption mechanism is also illuminated from the NMR spectra. The regeneration heat (equal to absorption enthalpy) was calculated to be − 55.7 kJ·mol−1 from absorption isotherm of three different temperatures. The recyclability was evaluated from the vacuum regeneration (ten consecutive absorption–desorption cycles) and dynamic thermal regeneration, achieving the regeneration efficiency of more than 95 % and 99 %, respectively. All these experimental data indicate that the AAIL-based multi-tertiary-amines aqueous solution may be good candidate absorbent in terms of rapid efficient capture of CO 2. [ABSTRACT FROM AUTHOR]

The excellent mechanical properties of carbon nanotube (CNT) and low effective modulus of its forest makes CNT forest (CNTF) promising in dry adhesives. However, the low contact efficiency of buckled nanotube segments on the surface of the CNTF weakened its adhesion strength, which is far below the theoretical value. To improve the orientation, density, and arrangement of these nanotube segments, a layer of patterned aluminum was added to the conventional catalyst. Thus, a CNTF with densely-packed, horizontally-aligned surface nanotube segments was obtained. Nanoindentation results showed that the adhesion force of this CNTF could reach up to 13.69 mN under optimized conditions, nearly 5.5 times the best results of similar works. The results of coarse-grained (CG) simulations revealed the lateral stretching of these nanotube segments induced bond energy variation made a major contribution to the superior adhesion performance. The formation mechanism of these surface nanotube segments was also thoroughly analyzed. [Display omitted] • A patterned aluminum layer was introduced to the conventional CNT growth catalyst. • Buckled CNTs were turned into densely-packed, horizontally-aligned CNT segments. • This morphology change was a result of patterned aluminum regulating the catalyst. • The adhesion force was ∼6.9 times of regular forest and ∼5.5 times of similar works. • The coarse-grained simulation revealed the reason for this adhesion performance. [ABSTRACT FROM AUTHOR]

Potassium ion batteries are promisingly proposed for the large cale energy storage. However, potassium with large ion radius causes severe volumetric expansion of anodes during charging, which deteriorates the rate and the cycling performances of batteries. Herein, a honeycomb-like graphene monolith with rich micropores is prepared. The monolith is further applied as the binder-free anode for potassium ion batteries. It shows the remarkable rate performance with a capacity of 180 mAh g−1 at a current density of 10 A g−1, and it can stably run for 4000 cycles at 1 A g−1. Kinetic studies and theoretical analyses reveal that the large graphitic interlayer spacing, the nitrogen doping, and the 3D network structure can significantly promote the diffusion rate, the absorption of potassium ions, as well as the transports of electrons and ions. The graphene-based potassium ion batteries can thus boost the development of renewable energies. [Display omitted] • Defect-rich monolithic graphene with high specific surface area was prepared. • Zinc-guided graphene monolith was used as a binder-free potassium-storage anode. • Large interlayer spacing, nitrogen doping and 3D network improved performances. [ABSTRACT FROM AUTHOR]

Abstract: A simple and environmentally friendly approach for the preparation of graphene nanosheets decorated with silver nanoparticles (Ag NPs) has been developed by gamma irradiation at room temperature. Graphene oxide (GO) and silver ions are simultaneously reduced by the electrons generated from the radiolysis of solvent. The addition of ionic liquid plays an important role in GO reduction by scavenging oxidative radicals generated during irradiation. Besides, the ionic liquid also benefits the dispersion and size distribution of Ag NPs. Raman signals of the obtained Ag-reduced graphene oxide are significantly enhanced, exhibiting obvious surface-enhanced Raman scattering activity. [Copyright &y& Elsevier]