Photocatalytic degradation of methylene blue under visible light by cobalt ferrite nanoparticles/graphene quantum dots

• Vo Chau Ngoc Anh,
• Le Thi Thanh Nhi,
• Le Thi Kim Dung,
• Dang Thi Ngoc Hoa,
• Nguyen Truong Son,
• Nguyen Thi Thao Uyen,
• Nguyen Ngoc Uyen Thu,
• Le Van Thanh Son,
• Le Trung Hieu,
• Tran Ngoc Tuyen and
• Dinh Quang Khieu

Beilstein J. Nanotechnol. 2024, 15, 475–489, doi:10.3762/bjnano.15.43

• heterojunctions limit the recombination of photo-induced electron–hole pairs and, thus, enhance catalytic decolourisation. Therefore, the CF/GQDs-200 sample was selected for further studies. The point of zero charge (pzc) of CF/GQDs-200 obtained by the pH drift method is 6.6 (see the inset of Figure 7b

• excellent heterojunctions between CoFe2O4 and GQDs. The former is favourable for more MB molecules to adsorb on the active sites of the photocatalysts, and the latter can facilitate the GQDs layers acting as electron acceptors, which are beneficial for suppressing the recombination of photogenerated

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• to their reduced form, and a small change in the stoichiometric ratio is sufficient for a significant change in the material’s work function [42]. Next, a series of NS-WOx/p-Si heterojunctions was constructed to investigate how the above variation in physicochemical properties influences the current

• thickness [51]. Evidently, more symmetric I–V characteristics are observed with increasing film thickness, which can be quantitatively verified from the calculated rectification ratio (RR) values of the NS-WOx/p-Si heterojunctions, as summarised in Table 1. The RR values are calculated employing Equation 3

• for the as-deposited and annealed NS-WOx/p-Si heterojunctions at three different applied voltages (V), viz. ±0.5, ±0.7, and ±1 V, where a higher value of RR indicates a stronger rectifying nature of a junction. As can be seen from Table 1, an increase in the film thickness minimizes the RR value of

CdSe/ZnS quantum dots as a booster in the active layer of distributed ternary organic photovoltaics

• Gabriela Lewińska,
• Piotr Jeleń,
• Zofia Kucia,
• Maciej Sitarz,
• Łukasz Walczak,
• Bartłomiej Szafraniak,
• Jerzy Sanetra and
• Konstanty W. Marszalek

Beilstein J. Nanotechnol. 2024, 15, 144–156, doi:10.3762/bjnano.15.14

• level. The energy gap was obtained from the Tauc diagram [57]. The levels correspond to a mixture of the levels obtained for pure CdSe and ZnS [58]. To evaluate the potential applicability of ternary mixtures, the volume heterojunctions of ITO/PEDOT:PSS/active layer/aluminum and ITO/active layer

• solar cells. Current–voltage characteristics for (a) ITO/active layer/Al and (b) ITO/PEDOT:PSS/P3HT:PCBM:QD/aluminium bulk heterojunctions cells. Designations of the nanodots used in the system. Refractive indices and extinction coefficient parameters for investigated quantum dots thin films. Roughness

Density functional theory study of Au-fcc/Ge and Au-hcp/Ge interfaces

• Olga Sikora,
• Małgorzata Sternik,
• Benedykt R. Jany,
• Franciszek Krok,
• Przemysław Piekarz and
• Andrzej M. Oleś

Beilstein J. Nanotechnol. 2023, 14, 1093–1105, doi:10.3762/bjnano.14.90

• provides helpful insight into the configuration of the interface and energy cost of point defects present in studied heterostructures. The calculations for the Au-fcc(011)/Ge(001) interface reveal the lowest interfacial energies for variants C and D of heterojunctions, consistent with available microscopic

Dual-heterodyne Kelvin probe force microscopy

• Benjamin Grévin,
• Fatima Husainy,
• Dmitry Aldakov and
• Cyril Aumaître

Beilstein J. Nanotechnol. 2023, 14, 1068–1084, doi:10.3762/bjnano.14.88

• blend. As in our previous works, we used the PTB7:PC71BM tandem. We refer the reader to our former reports [4][11] and review articles for a detailed introduction to KPFM on organic heterojunctions [20], and to the specificities of the PTB7:PC71BM blend. We limit ourselves here to recall that in these

• consistent with a well-known fact for fullerene derivative-based heterojunctions: PC71BM aggregates act as charge trapping centres. The trap release processes become the limiting factor determining the SPV decay dynamics. It is also important to note that although both sets of data (amplitude/phase) show

A visible-light photodetector based on heterojunctions between CuO nanoparticles and ZnO nanorods

• Doan Nhat Giang,
• Nhat Minh Nguyen,
• Duc Anh Ngo,
• Thanh Trang Tran,
• Le Thai Duy,
• Cong Khanh Tran,
• Thi Thanh Van Tran,
• Phan Phuong Ha La and
• Vinh Quang Dang

Beilstein J. Nanotechnol. 2023, 14, 1018–1027, doi:10.3762/bjnano.14.84

• , these methods still face problems, including the requirements of controlling defects, scale-up for mass production, or troubles relating to decoration uniformity [31][32]. Another method is to form heterojunctions of ZnO and other narrow-bandgap semiconductors (NiO [33], PbS [34], CdS [35], and MoS2[36

• dark current can be explained by the formation of a depletion region near the surface of the ZnO NRs resulting from oxygen absorption [43] and at p-type CuO NPs/n-type ZnO NRs heterojunctions under dark conditions. In addition, the recovery current obtained 1 min after turning off the visible light is

• 1.28, 1.03, 0.88, 0.61, and 0.42 mW·cm−2, respectively, owing to the fast charge separation at the p-type/n-type heterojunctions of CuO/ZnO. The separation of electron–hole pairs prolongs the lifetime of free electrons, leading to an enhanced photocurrent [45]. When the applied voltage is fixed at 2 V

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• GaInAsP:Zn transition layer (20 nm), the space charges at the two neighbouring heterojunctions overlap in this layer, leading to an asymmetric U-shape of the VCPD profile. The asymmetric U-shape is also present in the experimental profile in Figure 2c (dark blue and light blue parts emphasizing the decrease

Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35

• . Nanoarchitectonics of graphene nanoribbon heterojunctions has the potential to be a major technological breakthrough because of the rational design and by virtue of the extraordinary structural and electronic properties of such heterojunctions. However, graphene nanoribbon heterojunction structures made by bottom-up

• synthesis are usually difficult to incorporate into functional nanodevices because of the random arrangement of the heterojunctions. Bronner, Fischer, Crommie, and co-workers have developed a single hierarchical fabrication strategy via on-surface synthesis of graphene nanoribbons with a single

• heterojunction interface (Figure 10) [126]. This synthesis strategy is based on the difference in dissociation energies of C–Br and C–I bonds. The growth order of the block copolymers of graphene nanoribbons can be controlled. Such heterojunctions provide a viable platform that can be used directly for

Bismuth-based nanostructured photocatalysts for the remediation of antibiotics and organic dyes

• Akeem Adeyemi Oladipo and
• Faisal Suleiman Mustafa

Beilstein J. Nanotechnol. 2023, 14, 291–321, doi:10.3762/bjnano.14.26

• covered. The creation of Z-schemes, Schottky junctions, and heterojunctions, as well as morphological modifications, doping, and other processes are highlighted regarding the fabrication of bismuth-based photocatalysts with improved photocatalytic capabilities. A discussion of general photocatalytic

• techniques, metal/non-metal doping, introducing heterojunctions, and combining them with other materials. Synthesis approaches and performance enhancement The majority of the reported photocatalysts have been used in laboratory settings. Several fundamental requirements must be met to produce an efficient

• , element substitutions, intercalation compounds, plasmon sensitization, heterojunctions, and composites [72][110][118][119]. Several synthesis techniques have been used as summarised in Figure 4. Several synthesis procedures for bismuth-based photocatalysts have already been published [25][88][119][120

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• O–H bonds, which are caused by air humidity. To confirm the ability of the heterojunctions to enhance absorption in the visible-light region, the DRS spectra and Tauc plots were recorded and are presented in Figure 4. It can be easily observed in Figure 4a that the TNAs show a strong absorption edge

• carrier concentration in MoS2/TNAs sample such in Figure 4. The mechanism for the enhanced activity of the heterojunctions can be explained by the Mott–Schottky results in Figure 5b,c. Generally, all samples show positive slopes, which proves that they are n-type semiconductors [53]. Equation 2 shows the

• results previously published in [58]. Figure 7 presents the energy band diagram structure of the MoS2/TNAs and g-C3N4/TNAs heterojunctions based on the DRS and Mott–Schottky analysis results, which are summarized in Table 1. It is easily observed from Figure 7 that the heterostructures formed upon

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• variation in the structural morphology results in development of multiple active sites that ensure adsorption and effective charge transfer [10]. On the other hand, HBN has been utilised as a support material in the formation of heterojunctions owing to its large surface area and separation of charge

Recent trends in Bi-based nanomaterials: challenges, fabrication, enhancement techniques, and environmental applications

• Vishal Dutta,
• Ankush Chauhan,
• Ritesh Verma,
• C. Gopalkrishnan and
• Van-Huy Nguyen

Beilstein J. Nanotechnol. 2022, 13, 1316–1336, doi:10.3762/bjnano.13.109

• of heterojunctions, crystal plane management, and defect development, to enhance the photocatalytic efficacy of pristine Bi-based photocatalysts [1][30]. The photocatalytic processes of Bi-based photocatalytic applications have received little attention in environmental remediation and energy

• , the catalyst should have a high CB position and a low VB position, resulting in a large bandgap. These two prerequisites are not compatible. As a direct consequence of this, heterojunctions are produced. To create heterojunction photocatalysts, two semiconductor photocatalysts are combined [44][45

• . Constructing semi-conductor heterojunctions may be an effective technique for addressing the difficulties of individual Bi-based photocatalysts. This may be due to the changeable band structure and effective photoinduced electron–hole separation, which bestows them with higher capabilities [93]. It is possible

Rapid fabrication of MgO@g-C₃N₄ heterojunctions for photocatalytic nitric oxide removal

• Minh-Thuan Pham,
• Duyen P. H. Tran,
• Xuan-Thanh Bui and
• Sheng-Jie You

Beilstein J. Nanotechnol. 2022, 13, 1141–1154, doi:10.3762/bjnano.13.96

• heterojunction photocatalysts were synthesized by one-step pyrolysis of MgO and urea at 550 °C for two hours. The photocatalytic NO removal efficiency of the MgO@g-C3N4 heterojunctions was significantly improved and reached a maximum value of 75.4% under visible light irradiation. Differential reflectance

• visible light region, including nonmetal and noble-metal doping, metal deposition, and formation of heterojunctions [21][22]. The construction of heterojunction structures has shown its effectiveness in improving photocatalytic performance by enhancing the separation of charge carriers and optimizing the

• efficiency for NOx, NO, and NO2 [12]. However, these studies only focused on the synthesis of MgO from Mg(NO3)2·6H2O, increasing time and cost of the synthesis process. Commercial MgO as a precursor material for MgO@g-C3N4 heterojunctions has not been studied. Furthermore, there are no relevant reports on

Spindle-like MIL101(Fe) decorated with Bi₂O₃ nanoparticles for enhanced degradation of chlortetracycline under visible-light irradiation

• Chen-chen Hao,
• Fang-yan Chen,
• Kun Bian,
• Yu-bin Tang and
• Wei-long Shi

Beilstein J. Nanotechnol. 2022, 13, 1038–1050, doi:10.3762/bjnano.13.91

• photogenerated charges and resultant photocatalytic activity [26]. Up to date, a few semiconductors such as ZnO [39], TiO2 [19] and g-C3N4 [40] have been employed to construct heterojunctions with MIL101(Fe). The abovementioned MIL101-based heterojunctions are all traditional heterojunctions which promote the

• be improved by combining it with other suitable semiconductor materials to construct Z-scheme heterojunctions. Bismuth trioxide (Bi2O3), a metal oxide semiconductor with a bandgap of 2.8 eV, can be excited by visible light [43][44]. However, pure Bi2O3 exhibits poor photocatalytic activity due to the

• construct Bi2O3-based heterojunctions has attracted extensive interest. A large number of Bi2O3-based heterojunctions, such as Bi2O3/g-C3N4 [46], WO3/g-C3N4/Bi2O3 [47], Bi2O3/BiOCl [48], Bi2O3/ZnO [49], and Bi2O3/BiVO4 [50] have been synthesized. However, to the best of our knowledge, there is no report

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

• Viet Van Pham,
• Hong-Huy Tran,
• Thao Kim Truong and
• Thi Minh Cao

Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7

• the defects actively trapping electrons and the charge transfer described in the S-scheme model. These factors increase the lifetime of electron–hole pairs and free radicals. The finding of this work enables the generation of a new and innovative structures with S-scheme heterojunctions for

• ), Copyright 2018 Springer Nature. This content is not subject to CC BY 4.0. Proposed mechanisms for photocatalytic NO oxidation via interfacial charge migration over BiOBr/SnO2 p–n heterojunctions. Figure 8 was reprinted with permission from [70], Copyright 2020 American Chemical Society. This content is not

• generation architectural structure of heterojunctions toward visible-light-driven NO degradation”, article no. 117510, Copyright (2021), with permission from Elsevier. This content is not subject to CC BY 4.0. (a) Surface photovoltage spectroscopy, (b) transient photocurrent responses, (c) EIS Nyquist plots

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• diffractograms of Si NWs and Si/WO3 NWs. Figure 17g–j demonstrates the dynamic response of composite and pure Si NWs to NO2 at different concentrations at room temperature, and the response of the composite to different gases. The composite sensor with p–n heterojunctions successfully transferred charge carriers

• temperature, in comparison to pure BiVO4 (1.2) and other compositions of BiVO4 and rGO at different temperatures (80–200 °C). The outstanding enhancement in the response of the hybrid material with quick response and recovery times was attributed to the formation of p–n heterojunctions between rGO nanosheets

Nanoporous and nonporous conjugated donor–acceptor polymer semiconductors for photocatalytic hydrogen production

• Zhao-Qi Sheng,
• Yu-Qin Xing,
• Yan Chen,
• Guang Zhang,
• Shi-Yong Liu and
• Long Chen

Beilstein J. Nanotechnol. 2021, 12, 607–623, doi:10.3762/bjnano.12.50

• generate hydrogen under visible-light irradiation, for the first time. After that, g-C3N4 triggered substantial research interest [12][13][14]. Various strategies have been developed to improve the PHP activity of g-C3N4, such as introducing heterojunctions [15][16][17], copolymerization [18][19][20

• -substituted, benzene–1,3,6,8-tetrephenylpyrene-based 2D polymers (P73 and P74). P74 rendered a higher HER of 106 μmol·h−1 (50 mg) than P73 (68 μmol·h−1, 50 mg) due to the strongly electron-withdrawing 3-ethylrhodanine fragments in the periphery [89]. CP-based heterojunctions for PHP applications Besides D–A

• polymers, heterojunctions between CPs and other semiconductors have also been developed to facilitate the intermolecular charge transfer and transport. The interactions between the CPs and various semiconductors in the heterojunctions could involve strong covalent bonds, ionic bonds, or hydrogen bonds [90

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• according to the Anderson’s rule for heterojunctions: ΔEc = XAZO − XGaAs, ΔEv = Eg(AZO) – Eg(GaAs) + ΔEc. Measurements of the external quantum efficiency The EQE characteristics of the examined samples were presented in Figure 8a (A series) and Figure 8b (B series). The difference between SA10-passivated

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• , formation of heterojunctions, or size reduction [18][19]. Doping of WO3 with nickel improves the humidity sensing compared to neat WO3. Attributed to a greater number of electrons donated by Ni atoms, higher surface area, and smaller bandgap energy, Ni-doped WO3 has a faster response, higher sensitivity

• -type MOS and an n-type MOS (p–n heterojunctions) [6][18]. The p-type MOS NiO is not a very popular gas sensing material, because p-type MOS have, in general, a lower gas response than n-type MOS, such as WO3, ZnO, or SnO2 [22][23]. But p-type MOS are ideal doping agents [24]. NiO combined with WO3

• sensitivity towards NO2 [36]. In the combination of WO3 and rGO, p–n heterojunctions are formed. This leads to an increased NO2 response at room temperature [37]. Overall, MOS@rGO gas sensors are more selective and sensitive with a faster response and recovery rate even at room temperature [8]. The sensing

Mapping of integrated PIN diodes with a 3D architecture by scanning microwave impedance microscopy and dynamic spectroscopy

• Rosine Coq Germanicus,
• Peter De Wolf,
• Florent Lallemand,
• Catherine Bunel,
• Serge Bardy,
• Hugues Murray and
• Ulrike Lüders

Beilstein J. Nanotechnol. 2020, 11, 1764–1775, doi:10.3762/bjnano.11.159

• types and reveals both homo- and heterojunctions in FEOL layers. However, the very low signal recorded at the location of the quasi-intrinsic layer (I layer) does not enable one to distinguish this lightly doped layer since the recorded signal is close to zero, at the same level of the signal recorded

A self-powered, flexible ultra-thin Si/ZnO nanowire photodetector as full-spectrum optical sensor and pyroelectric nanogenerator

• Liang Chen,
• Jianqi Dong,
• Miao He and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1623–1630, doi:10.3762/bjnano.11.145

• can greatly improve the portability and durability of the flexible PDs. In this work, a new type of self-powered high-performance full-spectrum flexible PDs consisting of ultra-thin p-Si/n-ZnO nanowires (NWs) is fabricated. The working mechanism of PDs based on p-Si/n-ZnO heterojunctions for PENGs is

• external power source. Working mechanism of a PENG based on p-Si/n-ZnO NWs heterojunctions To illustrate the working mechanism of self-powered PDs, schematic diagrams for the different conditions are presented in Figure 2. In the dark, a depletion layer is formed at the heterojunction interface due to

High-responsivity hybrid α-Ag₂S/Si photodetector prepared by pulsed laser ablation in liquid

• Raid A. Ismail,
• Hanan A. Rawdhan and
• Duha S. Ahmed

Beilstein J. Nanotechnol. 2020, 11, 1596–1607, doi:10.3762/bjnano.11.142

• forward current as a function of the voltage (inset of Figure 11) using Equation 3: where Is is the saturation current of the heterojunction. The value of n for the heterojunctions prepared in Tu and Tu with CTAB was 4 and 2.7, respectively. The value reduction of n after adding CTAB indicated a

• remarkable improvement in junction characteristics. The value of turn-on voltage of the heterojunctions was estimated and found to be 2.2 and 1.8 V for heterojunctions prepared in pure Tu and with CTAB surfactant, respectively. Decreasing the turn-on voltage after adding the CTAB can be ascribed to a

• decrease in the electrical resistivity of Ag2S. Figure 12 illustrates the I–V characteristics under illumination of the heterojunctions at reverse bias. The photocurrent of the heterojunction increased from 460 to 1500 μA at 7.5 V after CTAB was added to the Tu solution. This result can be ascribed to the

Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS₂ field-effect transistors

• Jakub Jadwiszczak,
• Pierce Maguire,
• Conor P. Cullen,
• Georg S. Duesberg and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2020, 11, 1329–1335, doi:10.3762/bjnano.11.117

• repeatedly by adjacent line scans, increasing the effective delivered dose and shifting that region to a more acceptor-rich area. This leads to the observed ambipolar gate response for large IR values. The formation of these back-to-back heterojunctions may result in unconventional charge transport phenomena

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• -doped silicon nanowires (SiNWs). A rational strategy to obtain radial homo- and heterojunctions is to overcoat the as-grown nanowires within the same reaction chamber by implementing a conventional CVD process (e.g., thermal SiH4-CVD) yielding core–shell nanowires [14]. Although ideal epitaxial growth

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

• Vadim Morari,
• Aida Pantazi,
• Nicolai Curmei,
• Vitalie Postolache,
• Emil V. Rusu,
• Marius Enachescu,
• Ion M. Tiginyanu and
• Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

• contact on the p-type Si substrate. Figure 9 and Figure 10 compare the current–voltage characteristics of p-Si/n-Zn1−xMgxO heterojunctions for two films deposited by spin coating with x values of 0.10 (Figure 9) and 0.40 (Figure 10). One can see from Figure 9b and Figure 10b that in both cases the current

• , the investigated heterojunctions work as photodetectors at forward bias, while a classical p–n junction should function as a photodetector at reverse bias. Since the current–voltage characteristics are fit to straight lines in the log–log coordinates, it means that they correspond to a power function

• heterojunction with a Zn0.6Mg0.4O film, the current–voltage characteristics fit to the MG law both in the dark and under illumination (see Figure 10c). These observations suggest that the investigated heterojunctions work at forward bias as injection photodiodes [53][54]. A more detailed investigation of