The development of simple, reliable, and highly sensitive methods for dopamine (DA) quantification is of critical importance in biomedical diagnostics, yet challenges such as insufficient sensitivity and weak anti-interference capability remain. In this study, a type-II band-aligned CsPb2Br5/CdS heterojunction was constructed via a green and facile aqueous-phase in situ growth method for high-performance photoelectrochemical sensing. The high carrier mobility and superior light absorption coefficient of the perovskite material were leveraged, and the well-matched band structure with CdS facilitated the formation of the built-in electric field, by which the separation and transport of photogenerated electron-hole pairs were significantly enhanced and non-radiative recombination was effectively suppressed. Consequently, the sensor exhibited outstanding performance for DA detection, with a wide linear range from 0.3 to 300 mu M and an ultra-low detection limit of 0.0116 mu M. It also demonstrates high sensitivity, excellent selectivity, user-friendly operation, a rapid response, and good tolerance. This work provides a promising strategy for developing easily fabricated perovskite-based photoelectrochemical biosensors, demonstrating potential for the rapid detection of DA.

High-efficiency antimony sulfide (Sb2S3) solar cells have successfully learned from the device structure of perovskite solar cells and often use spiro-OMeTAD as the hole-transporting layer (HTL). However, the stability of spiro-OMeTAD under an atmospheric environment is poor. It is generally believed that copper-based semiconductor nanocrystals (NCs), demonstrating appropriate valence band maximum (VBM), remarkable stability, and abundant elements, are suitable for the HTLs. In practice, however, related research has mainly focused on perovskite solar cells. In this work, Cu2SnS3, Cu2ZnSnS4, and CuInS2 nanocrystals are synthesized by the hot injection method and successfully used as HTLs in high-efficiency Sb2S3 solar cells. Through hexanethiol ligand exchange, dense and continuous copper-based semiconductor nanocrystal films are prepared by the spin coating method. Furthermore, the device performances of Sb2S3 solar cells based on Cu2SnS3, Cu2ZnSnS4, and CuInS2 HTLs are up to 6.52, 6.70, and 7.06%, respectively. It shows a comparable performance with the traditional spiro-OMeTAD (7.10%) and significantly improved stability compared to the Sb2S3 solar cell based on the spiro-OMeTAD HTL in an air atmosphere. This work highlights the importance of HTL in achieving high-efficiency and stable Sb2S3 optoelectronic devices.

2D transition metal tellurides (TMTs) possess fascinating properties for applications in ferroelectrics and optoelectronics. Nevertheless, it is still challenging to grow high-quality 2D TMTs with the desired phase (especially high-temperature phase) because of the weak bonding between the transition metal and Te as compared to S and Se atoms. Here, a strategy of siliconizing-driven layer-by-layer growth is reported to synthesize 2D ZrTe2 and ZrTe3 crystals with high crystallinity and desired thickness. Both as-synthesized crystals exhibit large-area uniform phases and atomically precise layered stacking structures. 2D ZrTe2 shows type-II Weyl semimetal characteristics with negative magnetoresistance, and 2D ZrTe3 demonstrates the existence of charge density waves and intrinsic superconductivity. Theoretical study reveals that silicon atoms can infiltrate and isolate a single layer of zirconium atoms and allow them to be tellurized in a layer-by-layer manner. The work paves the way for the synthesis of layer-controlled 2D TMTs and lays a material foundation for their physical property research.

Lead halide perovskite quantum dots (QDs) have been extensively studied due to their excellent photoelectric performance. However, the stability of MAPbBr3 QDs is affected by inevitable factors such as light, heat, and moisture, which limits their practical applications. In this work, stable metal-organic framework UIO-66 was synthesized via a solvothermal method, and the composite MAPbBr3@UIO-66 was prepared through an in-situ growth method. Owing to the wide bandgap, small pore size, and regular geometric structure, UIO-66 can confine the size and uniformity of the perovskite QDs encapsulated within the framework, maximally preserving the luminescent properties of the perovskite QDs. Furthermore, UIO-66 isolates the perovskite QDs from contact with polar water molecules in the air, significantly enhancing the stability of the perovskite QDs. The synthesized composite material exhibits high stability and excellent optical performance, with a photoluminescence quantum yield (PLQY) of up to 78.9% in an air environment. After being stored under natural conditions for 35 days, it still retains 65% of its high luminescence intensity and fluorescence quantum efficiency. When packaged into green and white LEDs, the LEDs demonstrate high brightness and good monochromaticity, maintaining stable brightness even after 2.5 hours of continuous operation. These superior characteristics indicate that the composite material MAPbBr3@UIO-66 has great potential for application in LED technology.

Alkaline metal ion doping enhances the photocatalytic activity of g-C 3 N 4.

Our research presents a novel water-stable photoelectrochemical sensor based on CsPb2Br5/CdSe quantum dots for dopamine.

Conformal two-dimensional materials refer to an atomically-thin layered material that can closely adhere on the surface of any substrate.It is tightly coated on the substrate surface like a thin film,along with the contour of the substrate surface,and thus forms a new type of functional composite structural material.This conformal structural material not only inherits the original surface morphological characteristics of the substrate,but also endows the substrate with novel physical properties of two-dimensional materials to achieve new functions and stimulate new physical and chemical effects under the interaction between two-dimensional materials and the substrate.The introduction of special substrate structures can enable two-dimensional materials to transcend the limitations of two-dimensional space.Combining the planar structure of two-dimensional materials with the arbitrary curved structure of the substrate is an important way to enhance interactions between two-dimensional materials and the surrounding environment,greatly expanding the application fields of two-dimensional materials,and may even achieve the killer applications.On the basis of proposing the concept of conformal two-dimensional materials,this article first elucidates the mechanism of conformal growth of two-dimensional materials,reveals the influence of substrate features and structures on the conformal growth and conformity of two-dimensional materi-als,as well as explores the thermodynamic factors and spatial equilibrium conditions that affect material growth behaviors.Second,it classifies and summarizes current progress on the preparation methods,properties,and applications of conformal two-dimensional materials represented by open and confined structures of substrates.Finally,the challenges and future de-velopment directions in this field are discussed.

ZnO/g-C3N4 heterojunction modified with Ag nanoparticles (ZnO/CN/Ag) was synthesized by depositing ZnO nanorods/Ag nanoparticles onto g-C3N4 nanosheets. Under xenon lamp irradiation, 99% of Rhodamine B (RhB) was degraded by ZnO/CN/Ag-5% composite within 30 min, which was much higher than the degradation efficiency of ZnO and ZnO/CN. The synergistic effect of g-C3N4 and ZnO, along with the localized surface plasmon resonance effect of Ag NPs, contributes to the improvement of photocatalytic performance. Ag nanoparticle provides another charge transfer path from g-C3N4 to ZnO, which speeds up the separation of electron-hole pairs. Meanwhile, the catalyst had good stability and recyclability. Finite-difference time-domain method and the density functional theory were used to obtain the charge transfer process. The photodegradation process has been studied in depth.

Using solar energy for photocatalytic degradation of pollutants is a clean and effective method for treating the increasingly severe problem of environmental pollution. Herein, porous ZnO/Co3O4 3 O 4 cages with improved charge separation ability was designed via a facile ZIF-8@ZIF-67-derived approach for tetracycline (TC) photo- degradation. Great photodegradation performance and good stability were achieved. The degradation rate was as high as 97 % within 60 min. The enhancement mechanism of TC photodegradation was investigated. The porous structure of ZnO/Co3O4 3 O 4 produced a number of active sites. The effective utilized spectrum was extended from the ultraviolet to the red region. The presence of two mixed valence states of Cobalt, Co2+ 2 + and Co3+, 3 + , increased the density of defect states and was conducive to the adsorption of TC. The composite had a Z-scheme heterojunction, in which strong oxidative capacity can be maintained, combination of electrons and holes was greatly reduced and efficient charge transfer occurred. This study would give new insights into the design of new photocatalysts with synergetic enhancement effect for TC photodegradation.

Backward stimulated Mie scattering (BSMS) holds significant potential across various fields due to its superior properties. In this study, we demonstrate that metal-semiconductor hybrids of CdS shell and Au core markedly enhanced the BSMS compared with pure CdS nanoparticles. Theoretical analysis suggests that the enhancement should be attributed to multi-photon excitation and increased Anderson localization of light. The localized light interacts with the incident light, creating conditions conducive to BSMS, thereby improving efficiency and reducing the threshold. The enhanced localization of light is a result of the increased nonlinear refractive index induced by electron-sink effect. Importantly, we propose a novel strategy, on the basis of BSMS, to adjust the pulse duration of laser output in a broad range without any frequency shift.

As two typical materials in the field of photocatalysis, Ti3C2Tx MXene and TiO2 had the disadvantage of insufficient photocatalytic activity, defect engineering and carbon layer composite can effectively improve this problem. In this paper, carbon-supported TiO2 with rich oxygen vacancies (TiOx@C) was synthesized in situ by a simple one-step calcination method using few-layer Ti3C2Tx MXene as the precursor. Due to the existence of defect level, the band gap of TiOx was narrowed and the light absorption capacity was enhanced. In addition, TiOx was attached to the carbon layer in the form of particles, and the carbon layer will act as an excellent electron conductor to quickly transfer electrons to achieve the purpose of rapid photogenerative carriers separation. In the photocatalytic N2 reduction reaction, the large specific surface area of carbon layer can adsorb more N2 molecules for chemical reaction, the experimental results showed that TiOx@C showed excellent NH3 production performance (96.01 mu mol/L/h) under visible-light, which was 16.2 times that of TiO2 (5.94 mu mol/L/ h). UV-vis diffuse reflection spectra and fluorescence spectra respectively strongly demonstrated the enhanced light absorption and efficient carriers separation of photocatalysts. This work provides a basis for further investigation of the physicochemical properties of Ti3C2Tx MXene derivatives.

Metal ion-induced water pollution is attracting increasing public attention. Perovskite quantum dots and metal-organic frameworks (MOFs), owing to their outstanding properties, hold promise as ideal probes for detecting metal ions. In this study, a composite material, MAPbBr3@PCN-221(Fe), was prepared by encapsulating MAPbBr3 quantum dots with PCN-221(Fe), demonstrating high chemical stability and good reusability. The composite material shows a sensitive fluorescence turn-on signal in the presence of silver ions. The fluorescence intensity of the composite material exhibits a linear relationship with the concentration of Ag+ in the solution, with a low detection limit of 8.68 µM. Moreover, the fluorescence signal exhibits a strong selectivity for Ag+, enabling the detection of Ag+ concentration. This fluorescence turn-on signal originates from the Ag+-bridged energy transfer from the conductive band of MAPbBr3 to the excited state of the MOF, which is directly proportional to the concentration of silver ions. Simultaneously, this finding may open up a new possibility in artificial controlled energy transfer from perovskite to MOF for future development.

TiO 2 (rutile–anatase, R–A)/Ti 3 C 2 T x heterophase junction (HPJ)–Schottky junction (SHJ) composites oxidized in situ by Ti 3 C 2 T x MXenes were synthesized via a one-step hydrothermal method using Ti 3 C 2 T x MXenes as the Ti source and water as the solvent.

Metal-semiconductor bifunctional core-shell nanomaterials were studied using catalytic system Au@CdS as example that displayed surface plasmon resonance (SPR) effects and photocatalytic activity. Some mechanisms of photocatalytic activity of the studied nanomaterials were discussed. Surface-enhanced Raman spectroscopy (SERS) was used to monitor in situ the SPR-driven photocatalytic dimerization of 4-nitrothiophenol (pNTP) to 4,4′-dimercaptoazobenzene (DMAB). The transfer path of “hot” electrons in Au@CdS was tracked by monitoring Raman spectral changes of the probe molecule. Nanomaterials Au@CdS showed high catalytic activity in photocatalytic degradation of rhodamine 6G. The SPR-displaying metal-semiconductor nanocomposite was indicated to be an extremely promising photocatalytic and in-situ SERS probe.

Transition metal ion doping is an effective strategy by which to enhance the photocatalytic activity of semiconductor materials. Herein, Ni-doped TiO2/Ti3C2 photocatalysts were designed and fabricated using a simple dipping method and their catalytic performance was verified via the degradation of rhodamine B (RhB). Ni doping induces the formation of a defect energy level in TiO2, which shortens the transition distance of photogenerated electrons. Ti3C2 acts as a hole acceptor, which is conducive to the transfer of photogenerated charge. The results show that the Ni-doped TiO2/Ti3C2 heterojunction structure exhibits the lowest photoluminescence peak intensity, the highest instantaneous current, and excellent photocatalytic performance compared to TiO2/ Ti3C2 and TiO2. At optimal Ni content, the removal efficiency of RhB is 90%, around 3.7 times higher than that of pure TiO2. This work details the preparation of an excellent Ni-doped heterojunction structure for enhanced photocatalytic performance, demonstrating an effective strategy by which to improve the charge separation ability.

Copper-based nanomaterials are compelling for high-efficient, low-cost electrocatalytic CO2 reduction reaction (CO2RR) due to their exotic electronic and structural properties. However, controllable preparation of copper-based two-dimensional (2D) materials with abundant catalytically active sites, that guarantee high CO2RR performance, remains challenging, especially on a large scale. Here, an in situ vertical growth of scalable metallic 2D Cu2Te nanosheet arrays on commercial copper foils is demonstrated for efficient CO2-to-CH4 electrocatalysis. The edge-oriented growth of Cu2Te nanosheets with tunable sizes and thicknesses is facilely attained by a two-step process of chemical etching and chemical vapor deposition. These active sites abounding on highly exposed edges of Cu2Te nanosheets greatly promote the electroreduction of CO2 into CH4 at a potential as low as -0.4 V (versus the reversible hydrogen electrode), while suppressing hydrogen evolution reaction. When a flow cell is employed to accelerate the mass transfer, the faradaic efficiency reaches ∼63% at an applied current density of 300 mA cm-2. These findings will provide great possibilities for developing scalable, energy-efficient Cu-based CO2RR electrocatalysts.

A Z-Scheme heterojunction is fabricated in situ . Because of plenty of reactive sites, wide absorption spectra and rapid charge transfer, the high photocatalytic efficiency is obtained and maintained.

Two-dimensional transition metal dichalcogenides and semiconductor metal oxides have shown great potential in photocatalysis. However, their stability and efficiency need to be further improved. In this paper, porous ZnO nanorods with high specific surface area were prepared from metal-organic framework ZIF-8 by a simple hydrothermal method. A MoS2/ZnO composite was constructed by loading MoS2 onto the surface of porous ZnO nanorods. Compared with ZnO materials prepared by other methods, MoS2/ZnO prepared in this paper exhibits superior photocatalytic performance. The enhanced photocatalytic activity of the MoS2/ZnO composite can be attributed to the formation of heterojunctions and strong interaction between them, which greatly facilitate the separation of electrons and holes at the contact interface. In addition, due to the wide absorption region of the visible spectrum, MoS2 can greatly broaden the light absorption range of the material after the formation of the composite material, increase the utilization rate of visible light, and reduce the combination of electrons and holes. This study provides a new way to prepare cheap and efficient photocatalysts.

Inorganic lead halide perovskites have attracted wide attention in photovoltaic and photocatalytic applications due to their high photoelectric conversion efficiency. However, improving the stability and charge transfer ef-ficiency of perovskites remains a significant challenge, especially in polarity solvent-based photocatalytic ap-plications. Here, we successfully grew CsPb2Br5 particles on g-C3N4 to construct p-n heterojunctions in an aqueous solution. The prepared CsPb2Br5/g-C3N4 p-n heterojunctions exhibited enhanced photoelectrochemical and photocatalytic performance, as well as better environmental stability in polar solvents (such as water). This enhancement is considered that p-n heterojunctions can effectively promote the separation and transfer of photogenerated carriers and no ligands that hinder the charge transfer are used. The successful synthesis of ligand-free CsPb2Br5/g-C3N4 p-n heterojunction extends the application of perovskite materials in the fields of photoelectrochemistry and photocatalysis.

高中物理知识是一个大整体,非常系统化,以至于处于任何阶段的高中生出现理解断层或者遗漏某些知识点的时候,会表现出缺一漏万的现象,所以物理学科的学习对大部分学生来讲是比较难的.在高中物理学科教学的整个过程中,课后作业虽然只是其中的一环,但是它也是必不可少的.本文基于现存教学过程中作业设计与安排存在的弊端,提出了促进高中学生物理深度学习的高效作业设计方法.