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Paper‐based photodetectors have emerged as reliable candidates for wearable electronics due to their low‐cost, degradability and excellent bending properties. However, the application of quantum dots (QDs) to paper‐based devices remains a challenge due to the low carrier mobility. In this work, lead sulfide (PbS) QDs are successfully applied to paper‐based devices by constructing the amorphous indium gallium zinc oxide (a‐IGZO)/PbS QDs‐EDT heterojunction to enhance the photoconductive gain of the QDs film. The effect of different paper substrates are investigated on device performance and demonstrate that the heterojunction is not suitable for the fiber‐like paper substrate. Heterojunction devices based on Senyan paper and glass paper exhibit stable detection performance with detectivity of 1.71 × 1010 and 3.19 × 1011 Jones, respectively. Benefit from the unique micro‐morphology, the Senyan paper‐based device exhibits excellent bending resistance and remained stable after 1000 bends. [ABSTRACT FROM AUTHOR]

Nowadays, developing a cost-effective, easy-to-operate, and efficient signal amplification platform is of important to microfluidic paper-based analytical devices (μPAD) for end-use markets of point-of-care (POC) assay applications. Herein, an ultrasensitive, paper-based photoelectrochemical (PEC) bioassay platform is constructed by in situ grown ZnO/ZnIn2S4 heterojunctions onto paper fibers, which acted as photoactive signal amplification probes for enhancing the sensitivity of antibodies-based diagnostic assays, for the sensitive detection of alpha-fetoprotein (AFP) targets. The crystalline flake-like ZnIn2S4 composited with hexagonal nanorods (NRs) morphology of ZnO is an in situ grown, at the first time, onto cellulose fibers surface supported with Au nanoparticle (Au NP) modification to improve conductivity of the device working zone. The obtained composites on paper fibers are implemented as a flexible paper-based photoelectrode to realize remarkable performance of the fabricated μPAD, resulting from the enhanced PEC activity of heterojunctions with effective electron-hole pair separation for accelerating photoelectric conversion efficiency of the sensing process under light irradiation. Once the target AFP was introduced into the biosensing interface assistant, with a specific recognition interaction of AFP antibody, a drastically photocurrent response was generated, in view of the apparent steric effects. With the concentration increase of AFP targets, more immune conjugates could be confined onto the biosensing interface, eventually leading to the quantitative decrease of photocurrent intensity. Combined with an ingenious origami design and permitting the hydrophobic/hydrophilic conversion procedure in the bioassay process, the ultrasensitive PEC detection of AFP targets was realized. Under the optimized conditions, the level of AFP could be sensitively tracked by the prepared μPAD with a liner range from 0.1 to 100 ng mL−1 and limit of detection of 0.03 ng mL−1. This work provides a great potential application for highly selective and sensitive POC testing of AFP, and finally, developments for clinical disease diagnosis. [ABSTRACT FROM AUTHOR]

[Display omitted] The O-vacancy Bi 2 WO 6 /SrTiO 3 heterojunction photocatalyst with Z scheme photogenerated electron transfer mechanism was loaded on cellulose fibers to construct a visible light-responsive photocatalytic composite paper for efficient and recyclable degradation of organic dyes in water. The introduction of O vacancies in Bi 2 WO 6 by alkali etching increased the utilization rate of Bi 2 WO 6 for visible light and achieved effective regulation of the energy band structure and Fermi level, which transformed Bi 2 WO 6 /SrTiO 3 type-II heterojunction into Z scheme heterojunction. The light-excited electrons in the conduction band of O-vacancy Bi 2 WO 6 directly migrated to the valence band of SrTiO 3 , which improved the separation efficiency of photogenerated carriers and maximized the redox capability of semiconductors. Compared with other control papers, O-vacancy Bi 2 WO 6 /SrTiO 3 paper exhibited the best photocatalytic performance, and its degradation rate for rhodamine B could reach 71.1% under 100 min of Xe lamp irradiation. The O-vacancy Bi 2 WO 6 /SrTiO 3 paper also showed good photocatalytic cycle stability. Loading heterojunction on the cellulose fibers solved the problem of poor reusability and difficult in recovery for powder semiconductor photocatalyst in practical applications. This study provides a novel strategy for constructing Z scheme heterogeneity on cellulose fibers to prepare composite paper with high photocatalytic activity and good reusability. [ABSTRACT FROM AUTHOR]

Layered metal chalcogenide materials are exceptionally appealing in optoelectronic devices thanks to their extraordinary optical properties. Recently, their application as flexible and wearable photodetectors have received a lot of attention. Herein, broadband and high-performance paper-based PDs were established in a very facile and inexpensive method by rubbing molybdenum disulfide and titanium trisulfide crystals on papers. Transferred layers were characterized by SEM, EDX mapping, and Raman analyses, and their optoelectronic properties were evaluated in a wavelength range of 405–810 nm. Although the highest and lowest photoresponsivities were respectively measured for TiS3 (1.50 mA/W) and MoS2 (1.13 μA/W) PDs, the TiS3–MoS2 heterostructure not only had a significant photoresponsivity but also showed the highest on/off ratio (1.82) and fast response time (0.96 s) compared with two other PDs. This advantage is due to the band offset formation at the heterojunction, which efficiently separates the photogenerated electron–hole pairs within the heterostructure. Numerical simulation of the introduced PDs also confirmed the superiority of TiS3–MoS2 heterostructure over the other two PDs and exhibited a good agreement with the experimental results. Finally, MoS2 PD demonstrated very high flexibility under applied strain, but TiS3 based PDs suffered from its fragility and experience a remarkable drain current reduction at strain larger than ± 0.33%. However, at lower strains, all PDs displayed acceptable performances. [ABSTRACT FROM AUTHOR]

Solar-driven water splitting by inorganic semiconductor photocatalysts is considered a promising method to produce hydrogen fuel. Loading inorganic semiconductor on cellulose fiber to construct photocatalytic paper contributes to the dispersion and recycling of photocatalyst. In addition, the photocatalytic paper floating on water can build a solid–gas biphase photocatalytic interface (photothermal-generated steam/photocatalytic paper/hydrogen), replacing the traditional liquid–solid–gas triphase photocatalytic interface (liquid water/photocatalyst/hydrogen) for improving photocatalytic kinetics. Here, we design and synthesize a photocatalytic composite paper with zinc sulfide (ZnS) anchored onto cellulose fibers (CF) with the help of polydopamine (PDA). PDA achieves high load and uniform distribution of ZnS on cellulose fibers, and forms the ZnS/PDA heterojunction to increase photogenerated charge separation efficiency and photocatalytic stability. Solid–gas biphase photocatalytic interface constructed by the CF/PDA/ZnS composite paper minimizes the interface barriers of hydrogen transport and water molecular adsorption for improving hydrogen evolution rate. The CF/PDA/ZnS composite paper shows a high hydrogen production rate up to 18706.8 μmol h−1 g−1. Stable loading of ZnS/PDA heterojunction in composite paper contributes to the photocatalytic stability. In the third photocatalytic cycle, the hydrogen evolution rate of CF/PDA/ZnS composite paper remains 96.4%. This work inspires that anchoring of inorganic semiconductor on cellulose fibers with the help of PDA can be a promising strategy for designing efficient photocatalytic paper for solar hydrogen production. [ABSTRACT FROM AUTHOR]

• MoS 2 /Bi 2 S 3 heterojunction photodetectors were prepared on nylon paper substrates. • The performance is different when the photodetectors are prepared in different order. • The devices exhibit good photoresponse in the range of 365 nm-980 nm. • The response time of the MoS 2 /Bi 2 S 3 photodetector is only 53 ms under UV light. • The devices have excellent bendability and stability. Flexible photodetectors are receiving increasing attention due to their promising applications in wearable optoelectronic devices, bendable imaging sensors, and implantable optoelectronic devices. In this work, a novel strategy for constructing flexible photodetectors based on a hybrid heterojunction of Bi 2 S 3 and MoS 2 was proposed. The devices are fabricated on a biodegradable paper substrate using a simple hydrothermal process and vacuum filtration techniques and exhibit a broadband photoresponse from ultraviolet to near-infrared (NIR). Especially, the specific detectivity (D*) of the MoS 2 /Bi 2 S 3 photodetectors is 3.25 × 1010 Jones under 365 nm, and the rise/decay time is 0.053 s/0.119 s in the NIR region. In addition, the performance of Bi 2 S 3 /MoS 2 photodetectors realizes a maximum responsivity (R) of 27.45 mA/W and a fast response time (∼0.470 s). These devices exhibit a stable photoresponse under repeated bending. Inexpensive materials and easy fabrication techniques provide a viable strategy for the design and performance optimization of flexible bimetallic sulfide photodetectors. [Display omitted] [ABSTRACT FROM AUTHOR]

Dual‐ion batteries have been considered as a competitive energy‐storage device. However, owing to the lack of suitable high‐capacity density and rapid‐charging electrode materials, designing a cost‐effective and high‐performance dual‐ion battery is still a great challenge. Herein, an ultrahigh‐capacity dual‐ion battery is constructed based on a carbon‐nanotubes (CNTs) containing SnS2‐MoS2@CNTs heterojunction anode and highly crystalline free‐standing graphite paper serves as cathode. The SnS2‐MoS2@CNTs heterojunction consisting of ultrathin nanosheets was prepared via a facile two‐step hydrothermal method and shows flower‐like morphology and high crystallinity. Benefiting from the unique design concept, the graphite paper/SnS2‐MoS2@CNTs dual‐ion battery delivers a high capacity of 274.2 mAh g−1 at 100 mA g−1 and has an outstanding capacity retention of 95 % after 300 cycles under 400 mA g−1. Even at a high current density of 2 A g−1 the battery still retains a considerable capacity of 112.3 mAh g−1. More importantly, the battery shows an extremely low self‐discharge of 0.006 % h−1 after resting for 24 h. Characterization using SEM and XRD further demonstrate the excellent cycling stability and good reversibility. Consequently, this constructed dual‐ion battery could be a promising energy storage device and provide new insights for the design of high‐performance dual‐ion batteries. [ABSTRACT FROM AUTHOR]

Mercury ions (Hg2+) mediating in situ heterojunction formation strategy based on spatially separated dual working areas was developed to achieve sensitive detection of human immunoglobulin G. To be specific, the complex of antibody, the silicon dioxide, and thymine-rich hairpin DNA were immobilized onto the antigen and antibody-modified electrodes, forming a special sandwich type where T-Hg2+-T structure could accommodate Hg2+. The zinc ions from zinc sulfide (ZnS) photoelectric materials were captured by Hg2+ to convert ZnS to zinc sulfide-mercuric sulfide nanocomposite. Such ion exchange approach with spatially separated working electrodes endowed the sensing platform with lower background interference and high selectivity, which also avoided damage of illumination on biomolecules. In addition, by regulating the ion recognition probe, the protocol could be extended to numerous other fields like clinical diagnosis, environmental monitoring, and public safety. [ABSTRACT FROM AUTHOR]

In this work, 2,6-diaminoanthraquinone (DAAQ)-1,3,5-triformylphloroglucinol (TFP) COF/CuS heterojunction was supported on cellulose fibers with hyperbranched polyamide-amine (HPAMAM) as growth template and stabilizer to prepare composite paper for photocatalytic degradation of organic dyes in water. HPAMAM was grafted onto dialdehyde cellulose fibers (DACF) via Schiff base reaction. The intramolecular cavities of HPAMAM provided suitable sites for the growth of COF/CuS heterojunction, and the flexible polymer chains of HPAMAM were used to disperse and stabilize the COF/CuS heterojunction. COF provided an ideal framework for the adsorption, diffusion, and activation of organic dyes in water. And the photogenerated electron transfer path in the COF/CuS heterojunction formed a Z scheme model, which enhanced the separation efficiency of photogenerated electrons and maximized the redox potential for high photocatalytic activity. The DACF/HPAMAM/COF/CuS paper exhibited the highest photocatalytic reaction rate (k = 0.5549 min−1), 7.4 times higher than that of DACF/HPAMAM/COF paper and 6.2 times higher than that of DACF/HPAMAM/CuS paper. To the best of our knowledge, this is one of the best performances for photocatalytic degradation of organic dyes. The DACF/HPAMAM/COF/CuS paper also showed good photocatalytic cycling stability and structural stability. This study provides a strategy for constructing COF/inorganic semiconductor Z scheme heterojunction on cellulose fibers to prepare photocatalytic paper and demonstrates a breakthrough in the field of photocatalytic degradation of organic dyes in water. [ABSTRACT FROM AUTHOR]

Abstract: A cellulose paper based p–n junction device was fabricated by synthesizing the ZnO/CuO nanostructures via a hydrothermal process. The CuO nanospindles (NSs) were decorated on the surface of cellulose paper substrate by a simple soaking process. Subsequently, ZnO nanorod arrays were grown on the surface of the CuO NSs decorated cellulose paper (i.e., CuO NSs/paper) by the hydrothermal process. The synthesized ZnO/CuO nanostructures on cellulose paper exhibited good crystal and optical properties and favorably formed the p–n heterojunction with a rectifying behavior. [Copyright &y& Elsevier]

A model of the position of the edge of emitter-base junction in the base and collector current pre-exponential ideality factor in HBT transistor with a SiGe base is presented. The model is valid for transistors with nonuniform profiles of doping and Ge content. The importance of taking into account the dependence of the effective density of states in SiGe on local Ge content and that of electron diffusion coefficient in SiGe on drift field for modeling accuracy is studied. [ABSTRACT FROM AUTHOR]

The New Journal of Chemistry, published by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, contains a variety of articles on different topics in chemistry. The articles cover areas such as polydimethylsiloxane coatings, water oxidation, lithium-ion batteries, and photocatalytic reactions. The journal provides valuable insights for those interested in chemistry and covers a diverse range of research areas. The document is a list of research papers published in the journal Chemistry in 2024, including topics such as the electrocatalytic degradation of tetracycline, the construction of a supramolecular system for imaging nematic mesophase and nematode cells, insights into hydrogen bond strengths in microhydrated clusters, and the development of macrophage-red blood cell hybrid membranes for eliminating pathogens, endotoxins, and heavy metal ions from blood. [Extracted from the article]

TiO2 has been generally studied for photocatalytic sterilization, but its antibacterial activities are limited. Herein, TiO2 nanospheres with rutile/anatase heterophase junctions are prepared by a wet chemical/annealing method. The large BET surface area and pore size are beneficial for the absorption of bacteria. The rutile/anatase heterojunctions narrow the bandgap, which enhances light absorption. The rutile/anatase heterojunctions also efficiently promote the photogenerated carriers' separation, finally producing a high yield of radical oxygen species, such as •O2− and •OH, to sterilize bacteria. As a consequence, the obtained TiO2 nanospheres with rutile/anatase heterojunctions present an improved antibacterial performance against E. coli (98%) within 3 h of simulated solar light irradiation, exceeding that of TiO2 nanospheres without annealing (amorphous) and TiO2 nanospheres annealing at 350 and 550 °C (pure anatase). Furthermore, we design a photocatalytic antibacterial spray to protect the file paper. Our study reveals that the TiO2 nanospheres with rutile/anatase heterojunctions are a potential candidate for maintaining the durability of paper in the process of archival protection. [ABSTRACT FROM AUTHOR]

As commercial interest in flexible power-conversion devices increases, the demand for high-performance alternatives to brittle inorganic thermoelectric (TE) materials is growing. As an alternative, we propose a rationally designed graphene/polymer/inorganic nanocrystal free-standing paper with high TE performance, high flexibility, and mechanical/chemical durability. The ternary hybrid system of the graphene/polymer/inorganic nanocrystal includes two hetero­junctions that induce double-carrier filtering, which significantly increases the electrical conductivity without a major decrease in the thermopower. The ternary hybrid shows a power factor of 143 μW m−1 K−1 at 300 K, which is one to two orders of magnitude higher than those of single- or binary-component materials. In addition, with five hybrid papers and polyethyleneimine (PEI)-doped single-walled carbon nanotubes (SWCNTs) as the p-type and n-type TE units, respectively, a maximum power density of 650 nW cm−2 at a temperature difference of 50 K can be obtained. The strategy proposed here can improve the performance of flexible TE materials by introducing more heterojunctions and optimizing carrier transfer at those junctions, and shows great potential for the preparation of flexible or wearable power-conversion devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • A paper-based photoanode is developed for photoelectrochemical water splitting. • MoSe 2 nanosheet anchored CdS-ZnO array functional paper is prepared. • Tandem Z-scheme configuration with double IEFs and photothermal effect are integrated. • The flexible photoanode achieves admirable solar water splitting performance. Rational design of photoelectrode architectures is deemed as an effective solution to enhance efficiency of photoelectrochemical water splitting for conquering increasingly prominent environmental problems. Herein, a programmable flexible photoanode with built-in tandem Z-scheme configuration fabricated by in-situ growth of MoSe 2 -CdS-ZnO array with ultrathin nanosheet-interlaced-nanorod structure on the Au paper electrode, is firstly reported. By taking advantages of the interwoven nanonetwork structure, high conductivity as well as larger porosity of the as-fabricated Au paper electrode, a stable light-harvesting paper chip with fast transfer/separate mediators of the charge/carriers is thus integrated. By virtue of double internal electric fields (IEFs) and photothermal effect, the developed MoSe 2 -CdS-ZnO photoanode exhibits incident-photon-to-current efficiency of 52 % under 460 nm of light irradiation, and the current density reaches 2.4 mA cm−2 at 0.3 V versus normal hydrogen electrode, which is comparable with respect to current state-of-the-art "type-II-scheme", "surface-scheme", and cocatalyst-free photocatalysts (0.03–2.4 mA cm−2). Consequently, the paper-based photoanode achieves admirable photoelectrocatalytic hydrogen generation property (39.7 μmol cm−2 h-1). The synergistic effect of tailorable tandem Z-scheme configuration with double IEFs and delineating of 3D cross-linked network structure of the proposed photoanode in this work may open an avenue for constructing high-performance photoelectrochemical water splitting devices. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a list of papers featured in the issue, covering topics such as photocatalytic hydrogen generation, thermal performance of glass coatings, and Zn ion storage performance. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions approved training courses offered by the society. [Extracted from the article]

In this paper, simulation modeling was carried out using Sentaurus Technology Computer-Aided Design. Two types of high electron mobility transistors (HEMT), an AlGaN/GaN/AlGaN double heterojunction and AlGaN/GaN single heterojunction, were designed and compared. The breakdown characteristics and damage mechanisms of the two devices under the injection of high-power microwaves (HPM) were studied. The variation in current density and peak temperature inside the device was analyzed. The effect of Al components at different layers of the device on the breakdown of HEMTs is discussed. The effect and law of the power damage threshold versus pulse width when the device was subjected to HPM signals was verified. It was shown that the GaN HEMT was prone to thermal breakdown below the gate, near the carrier channels. A moderate increase in the Al component can effectively increased the breakdown voltage of the device. Compared with the single heterojunction, the double heterojunction HEMT devices were more sensitive to Al components. The high domain-limiting characteristics effectively inhibited the overflow of channel electrons into the buffer layer, which in turn regulated the current density inside the device and improved the temperature distribution. The leakage current was reduced and the device switching characteristics and breakdown voltage were improved. Moreover, the double heterojunction device had little effect on HPM power damage and high damage resistance. Therefore, a theoretical foundation is proposed in this paper, indicating that double heterojunction devices are more stable compared to single heterojunction devices and are more suitable for applications in aviation equipment operating in high-frequency and high-voltage environments. In addition, double heterojunction GaN devices have higher radiation resistance than SiC devices of the same generation. [ABSTRACT FROM AUTHOR]

An N-doped TiO 2 /MoS 2 heterojunction photocatalyst constructed by two-dimension MoS 2 nanosheets and N-doped TiO 2 nanoparticles was successfully synthesized by a hydrothermal method. The synthesized N-TiO 2 /MoS 2 composites were characterized by XRD, XPS, TEM, UV–vis DRS and PL, and its visible photocatalytic activity was evaluated by degradation of methylene blue. The results showed that N-doped TiO 2 /MoS 2 heterojunction photocatalyst achieved more enhanced photocatalytic activity compared with pure TiO 2 , MoS 2 and N-doped TiO 2 for degradation of MB. Trapping tests with different scavengers indicated that not hydroxyl radicals ( OH) but superoxide radicals ( O 2 − ) and photogenerated holes (h + ) were highly responsible for the degradation process. The reusable experiments showed that the prepared N-doped TiO 2 /MoS 2 heterojunction photocatalyst was stable during the photodegradation of MB and will have practical applications for environmental remediation. [ABSTRACT FROM AUTHOR]

Electrical carrier separation from a photoexcited photochromic molecule could be a promising method for controlling the photosensitivity of such a molecule. We report an efficient carrier separation from a photochromic diarylethene (DAE) molecule by adopting a device structure with a heterojunction consisting of an n-type diarylethene layer and a p-type layer of N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB). A photocurrent originating from carrier separation for the colored photostationary state was observed, even at zero applied voltage. The efficient carrier separation occurred at the interface between the DAE and NPB layers and was the result of the internal electrical field induced by the pn heterojunction. [ABSTRACT FROM AUTHOR]

In this paper, the geometric configuration, electronic properties, and optical characteristics of an InS/GaTe heterojunction have been computed using the foundational principles of density functional theory. The analysis indicates that when the interlayer distance is 3.88 Å, the binding energy is the most negative, indicating that the structure is the most stable. The bandgap of the two monolayers is larger than that of the heterojunction, which makes the photogenerated electrons of the heterojunction more easily excited. The InS/GaTe heterojunction is a type-II heterojunction that enhances the efficient dissociation of electron–hole pairs. In addition, the InS/GaTe heterojunction demonstrates strong absorption of ultraviolet light, rendering it suitable for applications in ultraviolet detectors and related fields. Furthermore, the bandgap electron transfer direction of the InS/GaTe heterojunction can be controlled by applying electrical force and mechanical pressure. The optical absorption coefficient of the InS/GaTe heterojunction can be adjusted to modify its optical properties. Finally, the possible future applications of the InS/GaTe heterojunction are discussed. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

The widespread use of antibiotics leads to the pollution of the water environment. Photocatalytic technology is considered as an effective way of removing antibiotics from the water environment. In this paper, a semi-embedded CdS/tubular g-C3N4 (CdS/TCN) heterojunction photocatalyst was designed and prepared by hydrothermal, in situ oil bath and thermal polymerization methods. Then Ni nanoparticles were loaded onto the surface of CdS/TCN by an in situ photoreduction method to form high performance photocatalyst Ni–CdS/TCN. The degradation rate of tetracycline hydrochloride (TCH) by Ni–CdS/TCN-6 was about 1.9 times higher than that of bulk carbon nitride (BCN) under visible light irradiation for 30 min. The high specific surface area, the effective heterojunction and loaded Ni broaden the light absorption range, narrow the band gap and improve the photogenerated carrier separation efficiency and migration rate. Beyond that, loaded Ni also inhibits photocorrosion and improves the stability of the photocatalyst. The present work provides a new way for designing a semi-embedded heterojunction photocatalyst. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional TiO2 nanoflowers (NFs) were prepared by a facile hydrothermal method, and Ag3PO4 was grown in situ following alkali treatment to design and synthesize a Ag3PO4/OH/TiO2 catalyst with excellent photocatalytic activity under visible light. The test results show that the photocatalytic degradation performance of TiO2 NFs after alkali treatment and Ag3PO4 loading is significantly improved. This is because the alkali treatment and the introduction of Ag3PO4 can provide a large amount of –OH, which can be converted to ˙OH under UV irradiation, followed by an increase in the number of active radicals to enhance the photocatalytic degradation performance. Meanwhile, the introduction of Ag3PO4 can effectively improve the light absorption ability of the photocatalyst. Moreover, the in situ growth of Ag3PO4 on TiO2 NFs can construct a high-quality Ag3PO4/TiO2 heterojunction to promote the charge separation and transport. Therefore, the degradation rate of Ag3PO4/OH/TiO2 can reach 90% after 30 min for degrading 3 mg L−1 RhB under visible light. The Ag3PO4/OH/TiO2 photocatalyst designed in the present work provides a new tool for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate all-solution processed three-unit (red/green/blue) white tandem QLEDs for the first time. The white tandem devices are achieved by serially connecting the red bottom sub-QLED, the green middle sub-QLED and the blue top sub QLED using the inter-connecting layer (ICL) based on ZnMgO/PEDOT:PSS heterojunction. With the proposed ICL, the two-unit tandem QLEDs exhibit a high current efficiency of 22.22 cd/A, while the three-unit white QLEDs exhibit a peak current efficiency of 4.75 cd/A at a high luminance of 4206 cd/m2 . Displays based on the developed white QLEDs exhibit a wide color gamut of 114% NTSC. This work confirms the effectiveness of the proposed ZnMgO/PEDOT:PSS ICL and the feasibility of making all-solution processed tandem white QLEDs by using the proposed ICL. [ABSTRACT FROM AUTHOR]

Photoelectrochemical sensors have outstanding advantages including high sensitivity and miniaturization for outdoor use. Recently, perovskite quantum dots have attracted significant attention due to their high photoluminescence quantum yield. Nonetheless, there is still a strong need to improve their performance in challenging aqueous biological applications. In this paper, based on the molecularly imprinted polymer encapsulation of CsPbBr3 perovskite quantum dot/TiO2 inverse opal heterojunction structures, linear photoelectrochemical detection of cholesterol in aqueous solution was obtained without the involvement of an enzyme. The attenuation of photocurrent intensity under intermittent irradiation within 900 s (45 on/off cycles) was only 8.6%, demonstrating the superior stability of CsPbBr3 based sensor here. At the same time, the minimum detection limit of 1.22 × 10−9 mol L−1 in buffer conditions was lower than that reported for cholesterol photoelectric sensors. It has also been shown that the photoelectrochemical sensor of CsPbBr3 here outperformed that of CH3NH3PbBr3, which is another important member of the perovskite family. Finally, the proposed photoelectrochemical sensor platform was successfully applied in the determination of cholesterol in challenging serum with satisfactory recovery. The synergism among CsPbBr3 perovskite quantum dots, TiO2 inverse opal structure and imprinted polymer has led to greatly improved water stability, super selectivity and sensitivity, thus promoting the development of perovskite-based biological sensors. [ABSTRACT FROM AUTHOR]

Selectivity improvement by the frequency tuning of Mg@ZnO–TiO2 nanoflake-based heterojunction devices under exposure to different volatile organic compounds is the prime focus of the present paper. The synthesis of Mg@ZnO–TiO2 nanoflakes was carried out using a solution process followed by a low-cost hydrothermal method. A capacitive measurement approach was used to find the resonant frequencies of the device in 2-butanone, acetone, 2-propanol, ethanol, and methanol environments in the frequency range from 0.001 to 220 kHz. A Cole–Cole plot derived from impedance measurements suggested that the device impedance consisted of capacitance (Cz = 2.01 pF and CT = 2.17 pF) and resistance (Rz = 13 552.2 kΩ and RT = 3500.574 kΩ) from the ZnO nanoflake layer and TiO2 thin film layer, respectively. The maximum capacitive responses to 2-butanone (C4H8O), acetone (C3H6O), 2-propanol (C3H8O), ethanol (C2H5OH), and methanol (CH3OH) were recorded at resonant frequencies of 1.000 kHz, 0.791 kHz, 0.702 kHz, 0.319 kHz and 0.103 kHz, respectively, at the corresponding temperature of 125 °C, 100 °C, 100 °C, 75 °C, and 75 °C, respectively. The device offered optimum capacitive responses of 221.32%, 242.65%, 317.09%, 373.96%, and 401.24% to 100 ppm of 2-butanone, acetone, 2-propanol, ethanol, and methanol, respectively. Experimental observation confirmed that the capacitive response inversely varied with the resonant frequency. Such an inverse relation was correlated with the dielectric variation at the junction interface, change in the molecular weights of VOCs, and their sticking coefficient. An equivalent circuit diagram with the help of adsorption–desorption isotherms and an energy band model is illustrated to correlate the device optimum capacitive response at the tuned frequencies under different VOC media. [ABSTRACT FROM AUTHOR]

A comparative analysis of three advanced architectures for tandem solar cells (SCs) is discussed, respectively: metal oxide, thin film, and perovskite. Plasmonic solar cells could further increase solar cell efficiency. Using this development, an innovative PV technology (an SHTSC based on metal oxides) represented by a four-terminal Cu2O/c-Si tandem heterojunction solar cell is investigated. The experimental and numerical modelling study defines the main aim of this paper. The experimental approach to SHTSCs is analysed: (1) a Cu2O layer is deposited using a magnetron sputtering system; (2) the morphological and optical characterization of Cu2O thin films is studied. The electrical modelling of silicon heterojunction tandem solar cells (SHTSCs) is discussed based on five simulation tools for the optimized performance evaluation of solar devices. The main novelty of this paper is represented by the following results: (1) the analysis suggests that the incorporation of a buffer layer can improve the performance of a tandem heterojunction solar cell; (2) the effect of interface defects on the electrical characteristics of the AZO/Cu2O heterojunction is discussed; (3) the stability of SHTSCs based on metal oxides is studied to highlight the degradation rate in order to define a reliable solar device. Perspectives on SHTSCs based on metal oxides, as well as Si perovskite tandem solar cells with metal oxides as carrier-selective contacts, are commented on. [ABSTRACT FROM AUTHOR]

In this paper, we report on a photocatalytic water-splitting device comprising a TiO2 photoanode combined with Se/TiO2heterojunction photovoltaic (PV) devices. A Se/TiO2PV device can supply its photo-induced open circuit voltage to a TiO2-Pt photoelectrochemical cell (PEC) in order to assist photoelectrolysis for H2 and O2 gas generation without external electrical sources. The open circuit voltage was increased from 0.65 V to approximately 3.2 V by the serial connection of five Se/TiO2PV devices. Hydrogen and oxygen bubbles were successfully generated by only light illumination without using any wired external voltage source. A photoanode with sol–gel derived porous TiO2films was used to increase the surface area to attain a stronger photocatalytic reaction. Microdot patterns of Pt were formed as the co-catalyst on a TiO2photoanode to suppress the back reaction of the photogenerated carrier. A Pt anode was formed on a glass substrate. Parameters related to the photocatalytic reaction, such as atmospheric pressure, the type of chemical additive, and the area ratio of Pt co-catalyst patterns to the surface area of the TiO2photoanode, were varied to generate a larger gas volume with the water-splitting device. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (QDs) and organic materials have great research potential in the field of optoelectronic devices. In this paper, MEH-PPV/CsPbBr3 heterojunction photodetectors (PDs) are prepared by spin coating method based on the good photoelectric properties of CsPbBr3 perovskite QDs and MEH-PPV. The MEH-PPV/CsPbBr3 heterojunction improves the energy level arrangement, and CsPbBr3 QDs can passivate the surface defects of MEH-PPV films to achieve effective charge separation and transfer, thus inhibiting the dark current and improving the photoelectric performance of the device. Under 532 nm laser irradiation, the responsivity (R) of MEH-PPV/CsPbBr3 heterojunction PD is 11.98 A W−1, the specific detectivity (D *) is 6.98 × 1011 Jones, and the response time is 15/16 ms. This work provides experience for the study of perovskite QDs and organic materials heterojunction optoelectronic devices. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including a cell concept based on silicon heterojunctions, a solution for high efficiency modules, and the use of microwave photoconductivity in metal thin films.

In this paper, a sensor based on a novel ZnCo2O4/ZnO nanosheet-like p–n heterostructure was designed using a one-step hydrothermal method and utilized to dramatically improve the sensitivity toward triethylamine (TEA) gas. The structure, constituent elements and their valence states of ZnCo2O4/ZnO were tested using various methods. The 5 at%-ZnCo2O4/ZnO sensor was found to have the best sensing performance. The response value of this sensor toward 100 ppm triethylamine (TEA) at the optimum operating temperature of 280 °C (78.68) was almost 12 times higher than that of the ZnO sensor (6.58). The TEA's linear response, superior to that of the pure ZnO sensor, is more selectable and reproducible when the concentration range is between 5 and 80 ppm. A heterostructure of p–n was designed to enhance the gas-sensitive response effectively. This study refines the mechanism of the heterojunction to improve its gas-sensitive performance and provides a new strategy for the design of gas-sensitive materials. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis is a potential solution to meet energy needs with green and inexhaustible solar energy. However, designing efficient and stable photocatalysts is a challenging task due to the limited ability to effectively separate electrons and holes. In this paper, by using a straightforward ethanol dispersion technique, we were able to combine ultrathin layered Cu-TCPP MOFs with g-C3N4 nanosheets, resulting in the creation of an extremely effective nano-composite photocatalyst with exceptional UV-vis activity. CT/CN heterojunctions displayed remarkable photocatalytic efficacy for the production of H2, with 3CT/CN showcasing a five-fold enhancement in photoactivity as compared to the unadorned g-C3N4. Based on the results of photoluminescence spectroscopy, electrochemical impedance spectroscopy, and electrochemical reduction, the considerably improved charge transfer and separation, together with the possible catalytic capability of uniformly distributed metal nodes in Cu-TCPP, are believed to be the underlying reason for the observed exceptional photoactivity. After thorough analysis, a potential process for charge transfer and segregation between g-C3N4 and Cu-TCPP has been suggested. [ABSTRACT FROM AUTHOR]

Ti3C2Tx has been extensively used as a promising sensing material for the construction of electrochemical sensors because of its excellent conductivity, surface area and mechanical properties, but the two-dimensional structure and poor catalytic activity of Ti3C2Tx limit the improvement of its analytical behavior. This paper reports a facile method for the synthesis of a Ti3C2Tx@gold nanoparticle-arginine- and serine-functionalized graphene quantum dot aerogel (Ti3C2Tx@Au–AS-GQD). AS-GQD was prepared by heating a mixture of citric acid, arginine and serine. The formed AS-GQD was used to reduce chloroauric acid to produce gold nanoparticles. The gold nanoparticles protonated with hydrochloric acid were dropped into a Ti3C2Tx aqueous solution to form Ti3C2Tx@Au–AS-GQD. The Ti3C2Tx@Au–AS-GQD shows one three-dimensional structure. Small gold nanoparticles were uniformly dispersed on the Ti3C2Tx sheets. The introduction of AS-GQD resulted in the formation of Schottky heterojunction and enhanced the catalytic activity. The electrochemical sensor fabricated with Ti3C2Tx@Au–AS-GQD exhibited high sensitivity, selectivity and repeatability in the electrochemical detection of chloramphenicol. The differential pulse voltammetric current at −0.6 V linearly increased with the increase in chloramphenicol within 0.003–100 μM, exhibiting a detection limit of 0.0012 μM (S/N = 3). The sensitivity of our sensor toward chloramphenicol was better than those of other electrochemical sensors. This study also paves an avenue for the construction of Ti3C2Tx composites with excellent catalytic activity in sensing, catalysis and energy storage and conversion. [ABSTRACT FROM AUTHOR]

SiC/Si and GaN/Si heterojunction technology has been widely used in power semiconductor devices, and SiC/Si VDMOS and GaN/Si VDMOS were proposed in our previous paper. Based on existing research, breakdown point transfer technology (BPT) was used to optimize SiC/Si VDMOS. Simulation results showed that the BV of the SiC/Si heterojunction VDMOS was considerably increased from 259 V to 1144 V, and Ron,sp decreased from 18.2 mΩ·cm2 to 6.03 mΩ·cm2 compared with Si VDMOS. In order to analyze the characteristics of the SiC/Si heterojunction structure deeply, the influence of the interface state characteristics of the SiC/Si heterojunction on the electrical parameters of VDMOS was analyzed, including electric field characteristics, blocking characteristics, output characteristics, and transfer characteristics. In addition, the influence of the interface state of the SiC/Si heterojunction on energy band characteristics was analyzed. The results showed that with an increase in the interfacial charge (acceptor) concentration, the p-type trap layer was introduced into the interface of the SiC/Si heterojunction, energy increased slightly, and the barrier height difference at the heterojunction increased, resulting in an increase in BV. At the same time, since the barrier height became higher, electrons did not flow easily, so Ron,sp increased. On the contrary, when a charge (donor) was introduced at the interface of the SiC/Si heterojunction, the number of electrons in the channel increased, resulting in an increase in the electron current, which is conducive to the flow of electrons, resulting in a decrease in Ron,sp. The energy band and other characteristics of devices with temperature were simulated at different temperatures. Finally, the effects of SiC/Si heterojunction interface states on interface capacitances and switching performances of VDMOS devices were also discussed. [ABSTRACT FROM AUTHOR]

Purpose: In this paper, we consider p–n-junctions, manufactured by diffusion or ion implantation in a heterostructures. We analyzed influence of existing in heterostructure mismatch induced stresses on the current-voltage characteristics of the p–n-junctions. We also introduce an analytical approach for analysis of mass and heat transfer in heterostructures with account changes of their parameters on time, as well as their nonlinearity and mismatch induced stresses. In this paper we introduce an analytical approach for prognosis of the considered processes. Design/methodology/approach: In this paper, we consider p–n-junctions, manufactured by diffusion or ion implantation in a heterostructures. We analyzed influence of existing in heterostructure missmatch induced stresses on the current-voltage characteristics of the p–n-junctions. We also introduce an analytical approach for analysis of mass and heat transfer in heterostructures with account changes of their parameters on time, as well as their nonlinearity and missmatch induced stresses. In this paper we introduce an analytical approach for prognosis of the considered processes. Findings: In this paper, we consider p–n-junctions, manufactured by diffusion or ion implantation in a heterostructures. We analyzed influence of existing in heterostructure missmatch induced stresses on the current-voltage characteristics of the p–n-junctions. We also introduce an analytical approach for analysis of mass and heat transfer in heterostructures with account changes of their parameters on time, as well as their nonlinearity and missmatch induced stresses. In this paper we introduce an analytical approach for prognosis of the considered processes. Originality/value: This paper is original. [ABSTRACT FROM AUTHOR]

Ferroelectric photovoltaic (PV) materials have garnered considerable interest because of their distinctive switchable PV characteristics. Nevertheless, their ability to function within a wide range of ambient temperatures was previously constrained. This paper describes the construction of ferroelectric capacitors featuring an Au/PZT (Pb(Zr 0. 40 Ti 0.60)O 3)/FTO (SnO 2 :F) heterojunction through the utilization of the sol-gel technique. The performance analysis findings indicate that the PZT material, following optimization of annealing temperature, displayed strong ferroelectric properties and notable frequency-dependent dielectric behavior. An increase in temperature (25°C∼300°C) revealed that short-circuit current density J sc exhibited an upward → downward → upward trend and reached 399.6 μA/cm2 at 300°C. Energy band analysis showed the presence of spontaneous polarization and a large work function difference between the bottom electrode FTO and the top electrode Au (∼0.42 eV) created a strong built-in electric field in the PZT films, which was conducive to the photogenerated carriers' separation and greatly improved the PZT film ferroelectric PV. In this paper, transparent ferroelectric materials were demonstrated for the first time to exhibit a photoelectric responsivity of up to 1.77 mA/W at a temperature of 300°C, offering a practical strategy for the implementation of transparent ferroelectric photovoltaic devices in high-temperature environments, particularly those subjected to intense solar energy harvesting and conversion. [ABSTRACT FROM AUTHOR]

The cooling requirement for long-wave infrared detectors still creates significant limitations to their functionality. The phenomenon of minority-carrier exclusion and extraction in narrow-gap semiconductors has been intensively studied for over three decades and used to increase the operating temperatures of devices. Decreasing free carrier concentrations below equilibrium values by a stationary non-equilibrium depletion of the device absorber leads to a suppression of Auger generation. In this paper, we focus on analyzing exclusion and extraction effects separately, based on experimental and theoretical results for a HgCdTe photodiode. To carry out an experiment, the n+-P+-π-N+ heterostructure was grown by metal organic chemical vapor deposition on CdTe-buffered GaAs substrate. In order to separate the extraction and exclusive junctions, three different devices were evaluated: (1) a detector etched through the entire n+-P+-π-N+ heterostructure, (2) a detector made of the P+-π photoconductive junction and (3) a detector made of the π-N+ photodiode junction. For each device, the dark current density–voltage characteristics were measured at a high-temperature range, from 195 K to 300 K. Next, the carrier concentration distribution across the entire heterostructure and individual junctions was calculated using the APSYS simulation program. It was shown that when the n+-P+-π-N+ photodiode is reverse biased, the electron concentration in the π absorber drops below its thermal equilibrium value, due to the exclusion effect at the P+-π junction and the extraction effect at the π-N+ junction. To maintain the charge neutrality, the hole concentration is also reduced below the equilibrium value and reaches the absorber doping level (NA), leading to the Auger generation rate's reduction by a factor of 2ni/NA, where ni is the intrinsic carrier concentration. Our experiment conducted for three separate detectors showed that the exclusion P+-π photoconductive junction has the most significant effect on the Auger suppression—the majority of the hole concentration drops to the doping level not only at the P+-π interface but also deep inside the π absorber. [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean, safe, and efficient energy carrier, is one of the hot energy sources that have attracted much attention. Mo2C, due to the introduction of C atoms, makes the atomic spacing of the Mo lattice decrease and changes the width of the d-band, which makes the electronic properties of Mo2C similar to that of Pt noble metals, exhibiting excellent electrochemical hydrogen precipitation performance. MoS2, due to its special crystal structure and tunable electronic structure, has been widely studied. In this paper, Mo2C nanoparticles were prepared by high-temperature carbonization, and then two-dimensional layered MoS2 were be loaded on Mo2C nanoparticles by the hydrothermal method to synthesize Mo2C/MoS2 composite catalysts. Their electrochemical hydrogen precipitation (HER) performance under acidic conditions was tested. The above catalysts were also characterized by modern material testing methods such as XRD, SEM, TEM, and XPS. The results showed that the composite catalysts exhibited the most excellent electrochemical hydrogen precipitation performance at Mo2C/MoS2-3, with the lowest overpotential at a current density of 10 mA cm−2, Tafel slope, and electrochemical impedance. At the same time, the electrochemically active area was dramatically enhanced, with good stability under prolonged testing. The catalytic activity was significantly improved compared with that of Mo2C and MoS2. The characterization and experimental results indicate that the heterogeneous structure of Mo2C and MoS2 formed a built-in electric field between the two, which accelerated the electron transfer efficiency and provided more active sites. The Mo2C/MoS2 composite catalyst is a low-cost, easy-to-prepare, and high-efficiency electrochemical hydrogen precipitation catalyst, providing a new idea for developing green and clean energy. [ABSTRACT FROM AUTHOR]

To solve the shuttling effect and transformations of LiPSs in lithium–sulfur batteries, heterostructures have been designed to immobilize LiPSs and boost their reversible conversions. In this paper, we have constructed AlN/InN heterojunctions with AlN with a wide band gap and InN with a narrow band gap. The heterojunctions show metallic properties, which are primarily composed of 2s, 2p N atoms and 5s, 5p In atoms. InN has relatively higher adsorptivity for LiPSs than AlN. Reaction profiles show that on the surface of AlN, there is a lower rate-limiting step than on that of InN, from S8 to Li2S6, and a higher rate-limiting step from Li2S4 to Li2S2, which is more favorable for InN during the reduction from Li2S4 to Li2S2. The heterojunction can realize the synergistic reaction of trapping–diffusion–conversion for LiPSs, in which AlN traps large Li2S8 and Li2S6, the heterojunction causes the diffusion of Li2S4, and InN completes the conversion of Li2S4 to Li2S. [ABSTRACT FROM AUTHOR]

In this paper, a SiGe/Si heterojunction inductive line tunneling tunnel field-effect transistor with source Schottky contact (SC HJLT-iTFET) is proposed and investigated by the Sentaurus Technology Computer Aided Design (TCAD) simulator. By utilizing an appropriate source Schottky metal, the need for multiple ion implantation and annealing steps required for traditional P–I–N TFETs can be avoided, and the problems of self-alignment and random dopant fluctuations (RDF) during ion implantation can be solved. A high ON-state current (I ON) is obtained as fully overlapping the source and gate by line tunneling mechanism dominated, the appropriate Si1− x Ge x mole fraction material in the source region and high-k gate dielectric employed can further improve I ON. The incorporation of the block layer effectively decreases the lateral electric field at the drain end to reduce the OFF-state current (I OFF). Furthermore, the proposed charge enhancement layer (CEL) on the SiGe channel can suppress the Fermi level pinning effect (FLP) and enhance the charge of the source region. Based on the feasibility of the practical fabrication process, and the rigorous simulations indicate that the device has an SSavg of 19.8 mV/dec and SSmin of 6.8 mV/dec at V D = 0.2 V, I ON of 2.27 × 10−6 A μ m−1, and an I ON/ I OFF ratio of 1.02 × 1010, with extremely fast switching speed. These features make the device suitable for future ultra-low power applications on the internet of things, artificial intelligence, and related fields. [ABSTRACT FROM AUTHOR]

In this paper, a novel asymmetric trench SiC MOSFET with a Poly-Si/SiC heterojunction diode (HJD-ATMOS) is designed to improve its reverse conduction characteristics and switching performance. This structure features an integrated heterojunction diode, which improves body diode characteristics without affecting device static characteristics. The heterojunction diode acts as a freewheeling diode during reverse conduction, reducing the cut-in voltage (Vcut-in) to a lower level than conventional asymmetric trench SiC MOSFET (C-ATMOS), while maintaining a similar breakdown voltage. Meanwhile, the split gate structure reduces gate-to-drain charge (Qgd). Through TCAD simulation, the HJD-ATMOS decreases Vcut-in by 53.04% compared to the C-ATMOS. Both Qgd and switching loss are reduced, with a decrease of 31.91% in Qgd and 40.29% in switching loss. [ABSTRACT FROM AUTHOR]

During the past decade, Gallium Oxide (Ga2O3) has attracted intensive research interest as an ultra-wide-bandgap (UWBG) semiconductor due to its unique characteristics, such as a large bandgap of 4.5–4.9 eV, a high critical electric field of ~8 MV/cm, and a high Baliga's figure of merit (BFOM). Unipolar β-Ga2O3 devices such as Schottky barrier diodes (SBDs) and field-effect transistors (FETs) have been demonstrated. Recently, there has been growing attention toward developing β-Ga2O3-based heterostructures and heterojunctions, which is mainly driven by the lack of p-type doping and the exploration of multidimensional device architectures to enhance power electronics' performance. This paper will review the most recent advances in β-Ga2O3 heterostructures and heterojunctions for power electronics, including NiOx/β-Ga2O3, β-(AlxGa1−x)2O3/β-Ga2O3, and β-Ga2O3 heterojunctions/heterostructures with other wide- and ultra-wide-bandgap materials and the integration of two-dimensional (2D) materials with β-Ga2O3. Discussions of the deposition, fabrication, and operating principles of these heterostructures and heterojunctions and the associated device performance will be provided. This comprehensive review will serve as a critical reference for researchers engaged in materials science, wide- and ultra-wide-bandgap semiconductors, and power electronics and benefits the future study and development of β-Ga2O3-based heterostructures and heterojunctions and associated power electronics. [ABSTRACT FROM AUTHOR]

In this paper, an analytical model has been developed to observe the recombination losses involved in a tunnel oxide passivated contact solar cell with a carrier-selective layer constituting polycrystalline silicon (poly-Si). The main focus of this paper is to observe the contribution of each component of recombination current density and its effect on open-circuit voltage, Voc. The effect of emitter saturation current density (Joe), surface recombination velocity, substrate thickness, and doping density of carrier-selective layer on Voc has been presented. The analysis indicates that Voc = 766 mV can be achieved for Joe = 2 fA/cm2, and a doping density of poly-Si > 1021cm−3 in a c-Si/SiO2/poly-Si contact for a 50- $\mu \text{m}$ -thick substrate in case of ideal surface passivation. For identical conditions, Voc attains a lower value of 750mV for a 180- $\mu \text{m}$ -thick substrate. The dependence of Voc on bandgap of tunnel layers has also been observed by considering other materials like Si3N4 and SiC. These results from the analyticalmodel have been compared with results froma simulation using automat FOR simulation of HETerostructures v2.5 and have been found to be in good agreement with each other. [ABSTRACT FROM AUTHOR]

In this paper, ultra-thin nanofiber PDI was obtained by self-assembly dispersion of commercial PDINH. A novel Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material was constructed by a simple solvothermal method. XRD, SEM, TEM, FT-IR and other characterization techniques proved the successful preparation of the Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material. By degrading chlortetracycline hydrochloride, it was found that the photocatalytic activity of Co/Ni-MOF-74@PDI was much higher than that of pure Co/Ni-MOF-74 and PDI. Subsequently, Co/Ni-MOF-74@PDI was used to activate H2O2 to further improve the degradation efficiency of chlortetracycline hydrochloride. It was found that the photocatalytic performance was greatly improved after the addition of 19.6 mM H2O2 to the system, and the degradation rate of chlortetracycline hydrochloride was 87% within 90 min. The electron transfer pathway and H2O2 activation mechanism of the Co/Ni-MOF-74@PDI composite photocatalyst were proved by free radical quenching experiments, electron paramagnetic resonance analysis and X-ray electron spectroscopy. Finally, the easy exfoliation point and degradation pathway of chlortetracycline hydrochloride were studied using density functional theory, UPLC-MS and toxicity evaluation software. It was found that the main active substances were h+, ˙O2, 1O2 and ˙OH, and the toxicity of chlortetracycline hydrochloride and its intermediates was evaluated. [ABSTRACT FROM AUTHOR]

In this paper, highly dispersed hierarchical coral spheres of CeO2/ZnO have been constructed through a facile template-free hydrothermal strategy, followed by an annealing treatment. The resulting coral spheres exhibit enhanced activity for acetone sensing compared with CeO2 or ZnO as well as excellent cyclability and long-term stability. At the optimum working temperature of 245 °C, by controlling the ratio of Ce/Zn, the highest response of the coral spheres towards 100 ppm acetone is up to 145, which is about 5.5 times that of ZnO coral spheres. The significantly improved gas sensing activity may be ascribed to the well-dispersed and assembled CeO2 nanoparticles on the surface of ZnO coral spheres and the heterojunctions between CeO2 and ZnO, which produced abundant oxygen vacancies in the CeO2/ZnO coral spheres. [ABSTRACT FROM AUTHOR]

Understanding the properties and structure of reactant water molecules at the electrolyte solution/electrode interface is relevant to know the mechanisms of hydrogen evolution reaction (HER). However, this approach has rarely been implemented due to the elusive local microenvironment in the vicinity of the catalyst. Taking the Ni−CeO2 heterostructure immobilized onto carbon paper (Ni−CeO2/CP) as a model, the dynamic behavior of adsorbed intermediates during the reaction was measured by in situ surface‐enhanced infrared absorption spectroscopy with attenuated total reflection configuration (ATR‐SEIRAS). Theoretical calculations are used in combination to comprehend the potential causes of increased HER activity. The results show that the O−H bond of adsorbed water at the electrolyte solution/electrode interface becomes longer for promoting the dissociation of water and accelerating the kinetically slow Volmer step. In addition, forming the Ni−CeO2 heterostructure interface optimizes the hydrogen adsorption Gibbs free energy, thus increasing HER activity. Therefore, the Ni−CeO2/CP electrode exhibits remarkably low HER overpotentials of 37 and 119 mV at 10 and 100 mA cm−2, which are close to commercial Pt/C (16 and 102.6 mV, respectively). [ABSTRACT FROM AUTHOR]

The activation capacity of molecular oxygen is an important indicator to evaluate the photocatalytic efficiency of photocatalysts. In this paper, WS2 nanosheet was deposited on hyper-crosslinked CTF-1-G (obtained by molecular expansion from covalent triazine framework CTF-1) to form a C-GW heterojunction, which promoted the photodegradation of pollutants and the activation of molecular oxygen. This novel C-GW heterojunction exhibited excellent degradation property for organic pollutants (tetracycline (TC), rhodamine B (RhB)) and activating molecular oxygen under visible light irradiation. Among them, C-GW15 could degrade 98% of 20 ppm TC in 60 min and 99% of 30 ppm RhB in 30 min, and it had the highest hydrogen generation rate and hydrogen production amount in 4 hours, which were 8.74 mmol h−1 g−1 and 34.94 mmol g−1, respectively. Meanwhile, C-GW15 had the strongest 3,3′,5,5′-tetramethylbenzidine oxidation capacity and could generate 1.83 μmol of ˙O2− in 60 min and the production of H2O2 was 20.8 μmol L−1 in 40 min. The results of this study clearly indicated that the combination of WS2 and CTF-1-G can enhance the visible light absorption capacity and photogenerated carrier separation efficiency, thus promoting the photocatalytic performance. Finally, a Z-type photocatalytic mechanism was proposed based on radical capture, molecular oxygen activation experiments and electron spin resonance analysis. These findings will extend the fundamental understanding of the Z-type photocatalytic mechanism and provide new opportunities for the rational design of CTF heterojunctions for the treatment of environmental pollution and clean energy conversion. [ABSTRACT FROM AUTHOR]

In this paper, the geometric structures and electron-optical properties of AlAs/GaS heterojunctions and Se-doped AlAs/GaS heterojunctions are calculated based on first-principles of density functional theory (DFT). At the same time, the influence of the AlAs layer's 5° rotation stacking method on the AlAs/GaS heterojunction is discussed. The results show that the AlAs/GaS heterojunction is a type-II van der Waals heterojunction (vdWH) with a direct bandgap of 0.974 eV, and the Z-scheme electron transfer mechanism is more conducive to the separation of photogenerated electrons and holes. Both semiconductor-to-metal transitions can be achieved by applying an external electric field and strain. Under the action of an external electric field and uniaxial strain, AlAs/GaS maintains the type-II energy band alignment throughout the process. When biaxial strain is applied, the heterojunction is accompanied by a direct–indirect bandgap transition. It is worth mentioning that the optical absorption of the AlAs/GaS heterojunction is significantly higher than that of the two monolayers, and the absorption range is wider. The above characteristics indicate that the AlAs/GaS heterojunction has wider applications in fields such as photodetectors. [ABSTRACT FROM AUTHOR]

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Accurate theoretical prediction of the band offsets at interfaces of semiconductor heterostructures can often be quite challenging. Although density functional theory has been reasonably successful to carry out such calculations, efficient, accurate semilocal functionals are desirable to reduce the computational cost. In general, the semilocal functionals based on the generalized gradient approximation (GGA) significantly underestimate the bulk bandgaps. This, in turn, results in inaccurate estimates of the band offsets at the heterointerfaces. In this paper, we investigate the performance of several advanced meta-GGA functionals in the computational prediction of band offsets at semiconductor heterojunctions. In particular, we investigate the performance of r2SCAN (two times revised strongly constrained and appropriately normed functional), rMGGAC (revised semilocal functional based on cuspless hydrogen model and Pauli kinetic energy density functional), mTASK (modified Aschebrock and Kümmel meta-GGA functional), and local modified Becke–Johnson exchange-correlation functionals. Our results strongly suggest that these meta-GGA functionals for supercell calculations perform quite well, especially, when compared to computationally more demanding GW calculations. We also present band offsets calculated using ionization potentials and electron affinities, as well as band alignment via the branch point energies. Overall, our study shows that the aforementioned meta-GGA functionals can be used within the density functional theory framework to estimate the band offsets in semiconductor heterostructures with predictive accuracy. [ABSTRACT FROM AUTHOR]