Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC₇₁BM-based organic photovoltaic cells

• Olivia Amargós-Reyes,
• José-Luis Maldonado,
• Omar Martínez-Alvarez,
• María-Elena Nicho,
• José Santos-Cruz,
• Juan Nicasio-Collazo,
• Irving Caballero-Quintana and
• Concepción Arenas-Arrocena

Beilstein J. Nanotechnol. 2019, 10, 2238–2250, doi:10.3762/bjnano.10.216

• ]. According to the analysis carried out by Wadia et al. [3], among 23 semiconducting materials, FeS2 is the best candidate for the development of large-scale solar cells at low cost (<2 × 10−6 ¢/W). Furthermore, FeS2 exhibits excellent optoelectronic properties such as a band gap of 0.8 to 1.38 eV [4][5][6][7

• electrochemical band gap energy, the valence and conduction band energies (EVB and ECB) were calculated using the following Equation 1 and Equation 2: and where E[onset,ox] and E[onset,red] are the onset potentials of the oxidation and the reduction relative to ferrocene/ferrocenium (Fc+/Fc), E[½(Fc)] is the half

• -wave ferrocene potential of 0.20 V, and the additional energy of 4.8 eV represents the difference to the vacuum level potential of the normal hydrogen electrode. Thus, we determine an EVB of −4.99 eV and an ECB of −4.20 eV, resulting in a reasonable band gap energy of 0.79 eV, which is in line with the

Improved adsorption and degradation performance by S-doping of (001)-TiO₂

• Xiao-Yu Sun,
• Xian Zhang,
• Xiao Sun,
• Ni-Xian Qian,
• Min Wang and
• Yong-Qing Ma

Beilstein J. Nanotechnol. 2019, 10, 2116–2127, doi:10.3762/bjnano.10.206

• mainly comprises the O 2p states, with a band gap energy (Eg) of 3.2 eV. Therefore, the photo-excitation of electron–hole pairs requires photon energies hν ≥ 3.2 eV (wavelength λ < 387 nm). This means that the photo-response range of TiO2 lies in the ultraviolet region, and it can only absorb less than 5

• study on C/F-codoped (001)-TiO2 concluded that C/F atoms preferentially replaced O atoms on the (001) face, resulting in a surface conduction layer that could promote the migration of photo-generated carriers [19]. N/P-codoping of (001)-TiO2 resulted in a reduction of the band gap from 3.20 to 2.48 eV

Improvement of the thermoelectric properties of a MoO₃ monolayer through oxygen vacancies

• Wenwen Zheng,
• Wei Cao,
• Ziyu Wang,
• Huixiong Deng,
• Jing Shi and
• Rui Xiong

Beilstein J. Nanotechnol. 2019, 10, 2031–2038, doi:10.3762/bjnano.10.199

• [7] and Li-ion batteries [8][9][10][11]. Like most TMOs, bulk MoO3 has a wide band gap (about 3.0 eV) and low electrical conductivity, which seems inappropriate for thermoelectric devices. However, the electrical properties (including band gap and conductivity) of MoO3 are strongly dependent on the

• –Ernzerhof (PBE) [20] pseudopotentials without spin–orbit interaction. Since the PBE functional fails to capture the electrical and optical properties of bulk MoO3 by a large margin (band gap of less than half of the experimental value), we also employ the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• composite nanomaterials using highly dispersed silicon carbide (SiC). The unique physical and chemical properties of silicon carbide – wide band gap (Eg = 2.4–3.2 eV), high Debye temperature 1400 K, high thermal conductivity of 4.9 W/cm·K, low reactivity to oxygen and water vapor – ensure the stability of

• ]. Taking into account the difference in the band gap (Eg) of 2H-SiC (Eg = 3.3 eV [39]) and 3C-SiC (Eg = 2.36 eV [40]) polytypes, and assuming that the position of the valence band for these polytypes does not vary significantly, we constructed a diagram of the band alignment for ZnO and 3C-SiC phases

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

• Petronela Prepelita,
• Ionel Stavarache,
• Doina Craciun,
• Florin Garoi,
• Catalin Negrila,
• Beatrice Gabriela Sbarcea and
• Valentin Craciun

Beilstein J. Nanotechnol. 2019, 10, 1511–1522, doi:10.3762/bjnano.10.149

• treatment on the ITO chemical composition. Using a Tauc plot, values of the optical band gap ranging from 3.17 to 3.67 eV were estimated. These values depend on the heat treatment and the thickness of the sample. Highly conductive indium tin oxide thin films (ρ = 7.4 × 10−5 Ω cm) were obtained after RTA

BiOCl/TiO₂/diatomite composites with enhanced visible-light photocatalytic activity for the degradation of rhodamine B

• Minlin Ao,
• Kun Liu,
• Xuekun Tang,
• Zishun Li,
• Qian Peng and
• Jing Huang

Beilstein J. Nanotechnol. 2019, 10, 1412–1422, doi:10.3762/bjnano.10.139

• have been studied and successfully applied as the photocatalytic carrier. As a result, well-dispersed, nanometer-sized TiO2 immobilized on diatomite is obtained in the present paper. Even when TiO2 is well-dispersed, the problem of the band gap is yet another impediment to overcome. The value of the

• band gap of TiO2 is determined to be 3.20 eV [20], which means the photocatalytic process can just occur under UV-light irradiation. As we all know, it is more meaningful to make full use of the visible light spectrum in photocatalysis. To solve this problem, many effective methods have been studied

• such as doping [21], sensitization [22], modification [23], coupled and supported semiconductors [24]. As an important bismuth oxyhalide semiconductor material, bismuth oxychloride (BiOCl) has gained extensive attention in photocatalysis [25][26]. BiOCl has a band gap of 3.05–3.55 eV [27], which allows

Construction of a 0D/1D composite based on Au nanoparticles/CuBi₂O₄ microrods for efficient visible-light-driven photocatalytic activity

• Weilong Shi,
• Mingyang Li,
• Hongji Ren,
• Feng Guo,
• Xiliu Huang,
• Yu Shi and
• Yubin Tang

Beilstein J. Nanotechnol. 2019, 10, 1360–1367, doi:10.3762/bjnano.10.134

• 700 nm, and according to the Kubelka–Munk function [29] and the plot of (αhν)2 as a function of hν (Figure S1, Supporting Information File 1), the band gap (Eg) of CBO could be estimated to be 1.76 eV, which is consistent with the value reported in [30]. All of the Au/CBO composites exhibited a better

Fe₃O₄ nanoparticles as a saturable absorber for giant chirped pulse generation

• Ji-Shu Liu,
• Xiao-Hui Li,
• Abdul Qyyum,
• Yi-Xuan Guo,
• Tong Chai,
• Hua Xu and
• Jie Jiang

Beilstein J. Nanotechnol. 2019, 10, 1065–1072, doi:10.3762/bjnano.10.107

• 710119, China Hunan Key Laboratory of Super Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha and 410083, China 10.3762/bjnano.10.107 Abstract Fe3O4 nanoparticles (FONPs) are magnetic materials with a small band gap and have well-demonstrated

• ultrafast recovery time of 18–30 ps [3]. FONPs can be classified as a semiconductor material (with a band gap of ≈0.3 eV), which can be modulated by tuning the nanoparticle diameter [4]. For the magnetite (Fe3O4) material of anti-spinel structure, Fe(II) and Fe(III) of the octahedral position of the crystal

Electronic and magnetic properties of doped black phosphorene with concentration dependence

• Ke Wang,
• Hai Wang,
• Min Zhang,
• Yan Liu and
• Wei Zhao

Beilstein J. Nanotechnol. 2019, 10, 993–1001, doi:10.3762/bjnano.10.100

• and high carrier mobility [7][8]. Unlike zero-band-gap graphene, the layer-dependent bandgap of black phosphorene ranges from 0.31 to 1.9 eV [9]. The hole-dominated mobility of phosphorene is up to 1000 cm2·V−1·s−1 theoretically [10], which is much higher than that of TMDs. These properties render

Structural and optical properties of penicillamine-protected gold nanocluster fractions separated by sequential size-selective fractionation

• Xiupei Yang,
• Zhengli Yang,
• Fenglin Tang,
• Jing Xu,
• Maoxue Zhang and
• Martin M. F. Choi

Beilstein J. Nanotechnol. 2019, 10, 955–966, doi:10.3762/bjnano.10.96

• energies on nanocluster sizes indicates that the optical luminescence of the samples comes from the quantum confinement effect. The band gap of the NCs increases with a decrease in the dimension of the AuNC quantum structure. Conclusion In this research, a highly polydisperse penicillamine-protected AuNC

Synthesis of novel C-doped g-C₃N₄ nanosheets coupled with CdIn₂S₄ for enhanced photocatalytic hydrogen evolution

• Jingshuai Chen,
• Chang-Jie Mao,
• Helin Niu and
• Ji-Ming Song

Beilstein J. Nanotechnol. 2019, 10, 912–921, doi:10.3762/bjnano.10.92

• attention because of the suitable band edge and band gap, as well as tunable optical properties [23][24][25][26][27][28]. For example, CdIn2S4 has been reported in various photoredox catalysis, such as organic photosynthesis, CO2 photoreduction and H2 evolution [29][30][31]. Despite these advances, the

• nanocomposites. It can be clearly observed that the light absorbance decreases in the visible light range upon addition of CdIn2S4 content in CISCCN nanocomposites. The band gap (Eg) of g-C3N4, CCN and CdIn2S4 can be estimated by plotting (αhν)2 as a function of the photon energy (Figure 6b), with α being the

• electrons on the hydrogen scale (about 4.5 eV), X is the electronegativity of the semiconductor, and Eg is the band gap energy of the semiconductor. The edge of the valence band (VB) and conduction band (CB) of g-C3N4, CCN and CdIn2S4 are summarized in Table 1. The separation–recombination rate of photo

Rapid, ultraviolet-induced, reversibly switchable wettability of superhydrophobic/superhydrophilic surfaces

• Yunlu Pan,
• Wenting Kong,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2019, 10, 866–873, doi:10.3762/bjnano.10.87

• heat treatment has been previously reported and was explained by the formation of Ti–O–H bonds under UV light, while heating of the surface results in the decrease in the concentration of Ti–O–H bonds [33][34]. As reported, due to the low band gap energy of TiO2, the photo-induced electron–hole pairs

A carrier velocity model for electrical detection of gas molecules

• Ali Hosseingholi Pourasl,
• Sharifah Hafizah Syed Ariffin,
• Mohammad Taghi Ahmadi,
• Razali Ismail and
• Niayesh Gharaei

Beilstein J. Nanotechnol. 2019, 10, 644–653, doi:10.3762/bjnano.10.64

• variation of GNR energy band gap, and conversion of GNR to a n-type or p-type semiconducting material depending on whether it is an acceptor or donor functional molecule [21]. On the other hand, the variation of the energy band gap could convert the GNR properties from metallic to semiconducting, or vice

• carriers over the density of carriers, and is given by [26]: where is the magnitude of velocity (m is electron mass and Eg is energy band gap), and is the Fermi–Dirac distribution function that indicates the probability of occupation of a state at each energy level [27]. The DOS indicates the number of

• direction is obtained as: For the bare AGNR, the value of the hopping integral parameter is t′ = 0 eV. The value of the DOS near the Fermi level would be equal to 0 (eV)−1 for the bare AGNR and the width of zero DOS area should be equivalent to the energy band gap value of bare AGNR. This is because there

Temperature-dependent Raman spectroscopy and sensor applications of PtSe₂ nanosheets synthesized by wet chemistry

• Mahendra S. Pawar and
• Dattatray J. Late

Beilstein J. Nanotechnol. 2019, 10, 467–474, doi:10.3762/bjnano.10.46

• effect. Apart from this, these TMDCs, for example MoS2 and MoSe2, show an indirect to direct band gap transition [13][14][15][16][17]. A 2D platinum diselenide (PtSe2) material has recently joined the growing class of stable TMDCs due its promising applications. The 2D PtSe2 has not been explored much to

• date due to difficulties in synthesis. It is well known that bulk PtSe2 is a semimetal in nature with a nearly zero band gap [18][19]. With the help of theoretical calculations such as density functional theory (DFT) and local-density approximations (LDAs), it has been observed that bulk PtSe2 shows a

• semimetallic nature and single-layer PtSe2 has a semiconducting nature with a bandgap of 1.2 eV. Bilayer PtSe2 is also a semiconducting material but with a slightly smaller band gap than the monolayer material [19]. This layer-dependent conversion of semimetal-to-semiconductor transition has potential for

Reduced graphene oxide supported C₃N₄ nanoflakes and quantum dots as metal-free catalysts for visible light assisted CO₂ reduction

• Md Rakibuddin and
• Haekyoung Kim

Beilstein J. Nanotechnol. 2019, 10, 448–458, doi:10.3762/bjnano.10.44

• all these interesting properties, pure g-C3N4 only weakly absorbs visible light due to its wide band gap and also has poor electrical conductivity [18]. An efficient way to increase the charge separation and electrical conductivity of g-C3N4 is to modify it with rGO. Besides the structural and

• electron affinity (EEA) and first ionization (Eion) energy; Ee is the energy of free electrons on the hydrogen scale (≈4.5 eV vs NHE); Eg is the band gap of semiconductors. The conduction and valence band potential value for GCN-5 are −1.01 and 1.05 eV, respectively, and is found to be lower than any CN

Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO₂ nanorods

• Julian Kalb,
• Vanessa Knittel and
• Lukas Schmidt-Mende

Beilstein J. Nanotechnol. 2019, 10, 412–418, doi:10.3762/bjnano.10.40

• nanostructures. Keywords: hydrothermal crystal growth; lithography; nanostructures; seed crystals; surface processes; oxides; Introduction Rutile TiO2 is a chemically stable semiconductor with a band gap of 3.1 eV [1]. Dependent on the kind of nanostructure and doping, it has outstanding electronic and

Geometrical optimisation of core–shell nanowire arrays for enhanced absorption in thin crystalline silicon heterojunction solar cells

• Robin Vismara,
• Olindo Isabella,
• Andrea Ingenito,
• Fai Tong Si and
• Miro Zeman

Beilstein J. Nanotechnol. 2019, 10, 322–331, doi:10.3762/bjnano.10.31

• ) of the NW array and thickness of supporting layers, the optimal NW dimensions were determined resulting in . It should be noted that an optimisation of the array periodicity could further improve the optical performance, particularly by choosing a value of Λ closer to the band-gap wavelength of c-Si

Site-specific growth of oriented ZnO nanocrystal arrays

• Rekha Bai,
• Dinesh K. Pandya,
• Sujeet Chaudhary,
• Veer Dhaka,
• Vladislav Khayrudinov,
• Jori Lemettinen,
• Christoffer Kauppinen and
• Harri Lipsanen

Beilstein J. Nanotechnol. 2019, 10, 274–280, doi:10.3762/bjnano.10.26

• nanoscale optoelectronics [1][2][3][4]. ZnO is an important direct band gap (≈3.3 eV), nontoxic, metal oxide semiconductor, which can readily be used for optoelectronic applications. The properties of ZnO can be tailored by changing the morphology of the structures. Thus, fabrication of ZnO having different

Study of silica-based intrinsically emitting nanoparticles produced by an excimer laser

• Imène Reghioua,
• Mattia Fanetti,
• Sylvain Girard,
• Diego Di Francesca,
• Simonpietro Agnello,
• Layla Martin-Samos,
• Marco Cannas,
• Matjaz Valant,
• Melanie Raine,
• Marc Gaillardin,
• Nicolas Richard,
• Philippe Paillet,
• Aziz Boukenter,
• Youcef Ouerdane and
• Antonino Alessi

Beilstein J. Nanotechnol. 2019, 10, 211–221, doi:10.3762/bjnano.10.19

• material such as silica can significantly change the optical absorption spectrum [15][18][19]. Indeed, this can result in additional absorption bands [19] and/or change the band gap [18]. For example, it was suggested that for long-duration laser pulses, point defects can provide “seed” electrons for

• in the glass network and the addition of Ge decreases the silica band gap [18][21][22][23]. The presence of Ge is associated with the appearance of new structures of optically active point defects such as the so-called germanium lone pair center (GLPC) [19][24]. This defect is responsible for an

• , showing that for the used pure silica sample [31] a higher energy is needed. The acquired results confirm the positive role of the Ge doping, which facilitates the material removal by reducing the glass band gap and the presence of the Ge-related defects. By comparing the samples produced with different

Uniform Sb₂S₃ optical coatings by chemical spray method

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Ilona Oja Acik,
• Arvo Mere and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

• sulfide (Sb2S3), an environmentally benign material, has been prepared by various deposition methods for use as a solar absorber due to its direct band gap of ≈1.7 eV and high absorption coefficient in the visible light spectrum (1.8 × 105 cm−1 at 450 nm). Rapid, scalable, economically viable and

• environmentally benign material. As Sb and S are abundant elements in the Earth’s crust, enough raw materials can be supplied to manufacture large quantities of Sb2S3 in the long term. Sb2S3 can be applied as the inorganic absorber in solar cells due to its direct band gap of ≈1.7 eV [1][2]. Sb2S3, prepared by a

• -brown layers. Furthermore, in our previous paper, 250 °C was found to be too high a deposition temperature to obtain sufficient coverage of TiO2 substrate by polycrystalline Sb2S3 thin films, despite the suitable band gap of 1.6 eV and high phase purity [12]. Restricted to deposition temperatures in the

Amorphous Ni_xCo_yP-supported TiO₂ nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

• Yong Li,
• Peng Yang,
• Bin Wang and
• Zhongqing Liu

Beilstein J. Nanotechnol. 2019, 10, 62–70, doi:10.3762/bjnano.10.6

• heterojunction can lower the band gap of the material thus augment the conductivity. The material band gap can be calculated by measuring the optical absorption edge in UV–vis DRS, shown in Figure 5f. It is observed that the absorption edge showed a red shift after electrodeposition of Ni–P and NiCoP. The

• absorption edges are 398, 405, and 488 nm for TNAs, Ni–P/TNAS, and NixCoyP/TNAs, corresponding the band gaps of 3.12, 3.06, and 2.54 eV, respectively. Sample NixCoyP/TNAs had a band gap 0.52 eV lower than that of Ni–P/TNAs. This indicates that the binary-metal phosphides synthesized via electrodeposition

Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics

• Franziska Ringleb,
• Stefan Andree,
• Berit Heidmann,
• Jörn Bonse,
• Katharina Eylers,
• Owen Ernst,
• Torsten Boeck,
• Martina Schmid and
• Jörg Krüger

Beilstein J. Nanotechnol. 2018, 9, 3025–3038, doi:10.3762/bjnano.9.281

• voltage (VOC) for the CISe microcells is more than twice as high as the one reached by the CIGSe absorbers. According to the dependence of band-gap energy on the Ga content, the opposite behavior would be expected. This observation points to the fact that the intermixing of In and Ga in the quaternary

Time-resolved universal temperature measurements using NaYF₄:Er³⁺,Yb³⁺ upconverting nanoparticles in an electrospray jet

• Kristina Shrestha,
• Arwa A. Alaulamie,
• Ali Rafiei Miandashti and
• Hugh H. Richardson

Beilstein J. Nanotechnol. 2018, 9, 2916–2924, doi:10.3762/bjnano.9.270

• depending upon the wavelength of the interrogating light. We have shown that the photoluminescence of erbium ions embedded in a wide-band-gap matrix is temperature-dependent [12] and have used the emission to determine the local temperature of optically excited gold nanostructures at an interface. The

Site-controlled formation of single Si nanocrystals in a buried SiO₂ matrix using ion beam mixing

• Xiaomo Xu,
• Thomas Prüfer,
• Daniel Wolf,
• Hans-Jürgen Engelmann,
• Lothar Bischoff,
• René Hübner,
• Karl-Heinz Heinig,
• Wolfhard Möller,
• Stefan Facsko,
• Johannes von Borany and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2018, 9, 2883–2892, doi:10.3762/bjnano.9.267

• exception of optical applications. The latter is due to its indirect band gap in the bulk state. Benefiting from their reduced size, Si NCs show optical activity [1][2] and quantum confinement behavior [3] and have inspired novel applications in microelectronics [4], optics [1] and photovoltaics [5][6]. In

Two-dimensional semiconductors pave the way towards dopant-based quantum computing

• José Carlos Abadillo-Uriel,
• Belita Koiller and
• María José Calderón

Beilstein J. Nanotechnol. 2018, 9, 2668–2673, doi:10.3762/bjnano.9.249

• describe shallow states in semiconductors, thus the band gap energy of the considered material has to be much larger than the binding energies EB. In order to implement this condition, we consider the generally unknown dielectric constant as a free parameter and estimate its minimum value required for the

• binding energy to fulfill the condition EB < Eg/2 as a function of the band-gap energy Eg and the effective mass on the conduction band, see Figure 3. Based on the known values of ε, an estimate ε ≤ 5 seems reasonable. This corresponds in the rainbow color code in Figure 3 to the yellow–orange–red region

• small ε region is expanded. In general, in this yellow–orange–red region we find the first three materials in Table 1, and possibly silicene and germanene if their band gap energies were suitably enhanced. In order to estimate binding energies and Bohr radii, we assume ε ≈ 5 for the first three