Nanostructured SnO₂–ZnO composite gas sensors for selective detection of carbon monoxide

• Paul Chesler,
• Cristian Hornoiu,
• Susana Mihaiu,
• Cristina Vladut,
• Jose Maria Calderon Moreno,
• Mihai Anastasescu,
• Carmen Moldovan,
• Bogdan Firtat,
• Costin Brasoveanu,
• George Muscalu,
• Ion Stan and
• Mariuca Gartner

Beilstein J. Nanotechnol. 2016, 7, 2045–2056, doi:10.3762/bjnano.7.195

• , 060021 Bucharest, Romania National Institute for Research and Development in Micro-technologies, 077190 Bucharest, Romania, Romelgen SRL, Bucharest, Romania 10.3762/bjnano.7.195 Abstract A series of SnO2–ZnO composite nanostructured (thin) films with different amounts of SnO2 (from 0 to 50 wt %) was

• . It was found that the sensing performance was influenced by the amount of oxide components present in the composite material. Improved sensing performance was achieved for the ZnO (98 wt %)–SnO2 (2 wt %) composite as compared to the sensors containing only the pristine oxides. The sensor response

• , cross-response and recovery characteristics of the analyzed materials are reported. The high sensitivity (RS = 1.21) to low amounts of CO (5 ppm) was reported for the sensor containing a composite sensitive film with ZnO (98 wt %)–SnO2 (2 wt %). This sensor response to CO was five times higher as

The difference in the thermal conductivity of nanofluids measured by different methods and its rationalization

• Aparna Zagabathuni,
• Sudipto Ghosh and
• Shyamal Kumar Pabi

Beilstein J. Nanotechnol. 2016, 7, 2037–2044, doi:10.3762/bjnano.7.194

• Al2O3 nanoparticle loading and particle size. Lee et al. [25] have investigated the thermal conductivity of Al2O3, SiC, Ni, ZnO and multiwalled carbon nanotubes (MWCNTs) in liquid gallium using LFM. They reported that the thermal conductivity measured by LFM was not accurate because of the uncertainty

Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

• Marwa Akkari,
• Pilar Aranda,
• Abdessalem Ben Haj Amara and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1971–1982, doi:10.3762/bjnano.7.188

• Bizerte, University of Carthage, 7021 Zarzouna, Tunisia 10.3762/bjnano.7.188 Abstract In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the

• first step, intermediate silica–organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP) dispersed in 2-propanol were incorporated under

• ultrasound irradiation to the silica–organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP) homogeneously assembled to the clay–SiO2 framework. In the case of montmorillonite the

Effect of nanostructured carbon coatings on the electrochemical performance of Li_1.4Ni_0.5Mn_0.5O_2+x-based cathode materials

• Konstantin A. Kurilenko,
• Oleg A. Shlyakhtin,
• Oleg A. Brylev,
• Dmitry I. Petukhov and
• Alexey V. Garshev

Beilstein J. Nanotechnol. 2016, 7, 1960–1970, doi:10.3762/bjnano.7.187

• modification, namely other cathode materials (LiMnPO4 [11], LiMn2O4 [12], LiCoO2 [13], LiNiO2 [14]) or simple binary compounds such as CaF2 [15], TiO2 [16], ZnO [17] and Al2O3 [18]. During the assembly of the lithium-ion cells, the cathode materials are always mechanically mixed with carbon black in order to

Ferromagnetic behaviour of ZnO: the role of grain boundaries

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2016, 7, 1936–1947, doi:10.3762/bjnano.7.185

• Materials Science, Russian Academy of Sciences, Leninsky prospect 49, 117991 Moscow, Russia 10.3762/bjnano.7.185 Abstract The possibility to attain ferromagnetic properties in transparent semiconductor oxides such as ZnO is very promising for future spintronic applications. We demonstrate in this review

• that ferromagnetism is not an intrinsic property of the ZnO crystalline lattice but is that of ZnO/ZnO grain boundaries. If a ZnO polycrystal contains enough grain boundaries, it can transform into the ferromagnetic state even without doping with “magnetic atoms” such as Mn, Co, Fe or Ni. However, such

• doping facilitates the appearance of ferromagnetism in ZnO. It increases the saturation magnetisation and decreases the critical amount of grain boundaries needed for FM. A drastic increase of the total solubility of dopants in ZnO with decreasing grain size has been also observed. It is explained by the

A new approach to grain boundary engineering for nanocrystalline materials

• Shigeaki Kobayashi,
• Sadahiro Tsurekawa and
• Tadao Watanabe

Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176

• revealed that the electrical resistivity of individual grain boundaries strongly depends on the grain boundary character and structure from fundamental studies with orientation-controlled bicrystalline or coarse-grained metallic (Al) [123][124], semiconductor (Si) [125][126], and ceramic materials (ZnO

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

• Suneel Kumar,
• Rahul Sharma,
• Vipul Sharma,
• Gurunarayanan Harith,
• Vaidyanathan Sivakumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2016, 7, 1684–1697, doi:10.3762/bjnano.7.161

• the photocatalysts. In this work, we have investigated the role of reduced graphene oxide (RGO) support and the irradiation source on mixed metal chalcogenide semiconductor (CdS–ZnO) nanostructures. The photocatalyst material was synthesized using a facile hydrothermal method and thoroughly

• characterized using different spectroscopic and microscopic techniques. The photocatalytic activity was evaluated by studying the degradation of a model dye (methyl orange, MO) under visible light (only) irradiation and under natural sunlight. The results reveal that the RGO-supported CdS–ZnO photocatalyst

• performs considerably better than the unsupported CdS–ZnO nanostructures. In addition, both the catalysts perform significantly better under natural sunlight than under visible light (only) irradiation. In essence, this work paves way for tailoring the photocatalytic activity of semiconductor

Sb₂S₃ grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

• Erki Kärber,
• Atanas Katerski,
• Ilona Oja Acik,
• Arvo Mere,
• Valdek Mikli and
• Malle Krunks

Beilstein J. Nanotechnol. 2016, 7, 1662–1673, doi:10.3762/bjnano.7.158

• mesoporous TiO2 as the electron conductor, or when compared to a planar cell based on ALD-grown Sb2S3 [5]. The latter corroborates the benefit of a conformal coating and controlled thickness that is characteristic for ALD. As we have previously shown, the use of ZnO nanorods as the structured substrate and

• previous section. To further boost the current density, one is likely to benefit from the use of a stuctured electron-conducting substrate such as a layer of ZnO nanorods. Conclusion We focused on the optimization of the properties of Sb2S3 grown by chemical spray pyrolysis (CSP) of an ultrasonically

• to grow the Sb2S3 layer onto a structured substrate such as a ZnO nanorod layer. Experimental Technology of layers and solar cells We used a commercial 300 nm indium tin oxide (ITO) coated 1.1 mm glass with a sheet resistance of 10 Ω·sq.−1 from Zentrum für Sonnenenergie- und Wasserstoff-Forschung

Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

• Ionel Stavarache,
• Valentin Adrian Maraloiu,
• Petronela Prepelita and
• Gheorghe Iordache

Beilstein J. Nanotechnol. 2016, 7, 1492–1500, doi:10.3762/bjnano.7.142

• dark current and dark current density, respectively. The detectivity (D*) value is estimated in the range of 1015 Jones at about 1040 nm, which is comparable with that of ZnO nanoparticles-based photodetectors (D* ≈ 3.4 × 1015 Jones at 360 nm) [47]. The broad wavelength range (from about 450 to 1300 nm

• ≈ 42 µs) [49] or Ge–graphene–ZnO heterostructure infrared photodetectors (tr ≈ 40 µs and tf ≈ 90 µs) [50]. More importantly, these are the best results reported so far for photodetectors based on Ge-nps. We attribute this relatively fast response to the extremely high carrier mobility resulting from

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

• Vardan Galstyan,
• Elisabetta Comini,
• Iskandar Kholmanov,
• Andrea Ponzoni,
• Veronica Sberveglieri,
• Nicola Poli,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2016, 7, 1421–1427, doi:10.3762/bjnano.7.133

• , Via Valotti 9, 25133 Brescia, Italy Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA 10.3762/bjnano.7.133 Abstract A hybrid nanostructure based on reduced graphene oxide and ZnO has been obtained for the detection of volatile organic compounds. The

• sensing properties of the hybrid structure have been studied for different concentrations of ethanol and acetone. The response of the hybrid material is significantly higher compared to pristine ZnO nanostructures. The obtained results have shown that the nanohybrid is a promising structure for the

• monitoring of environmental pollutants and for the application of breath tests in assessment of exposure to volatile organic compounds. Keywords: chemical sensors; reduced graphene oxide (RGO); volatile organic compounds; zinc oxide (ZnO); Introduction Hazard analysis of critical control point (HACCP

High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis

• Bilel Chouchene,
• Tahar Ben Chaabane,
• Lavinia Balan,
• Emilien Girot,
• Kevin Mozet,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2016, 7, 1338–1349, doi:10.3762/bjnano.7.125

• , BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex, France 10.3762/bjnano.7.125 Abstract Ce-doped ZnO (ZnO:Ce) nanorods have been prepared through a solvothermal method and the effects of Ce-doping on the structural, optical and electronic properties of ZnO rods were studied. ZnO:Ce rods were characterized

• by XRD, SEM, TEM, XPS, BET, DRS and Raman spectroscopy. 5% Ce-doped ZnO rods with an average length of 130 nm and a diameter of 23 nm exhibit the highest photocatalytic activity for the degradation of the Orange II dye under solar light irradiation. The high photocatalytic activity is ascribed to the

• no marked detrimental effect on the photocatalytic activity was observed. Finally, recyclability experiments demonstrate that ZnO:Ce rods are a stable solar-light photocatalyst. Keywords: Ce doping; photocatalysis; solvothermal synthesis; ZnO rods; Introduction Due to the increasing pollution of

Viability and proliferation of endothelial cells upon exposure to GaN nanoparticles

• Tudor Braniste,
• Ion Tiginyanu,
• Tibor Horvath,
• Simion Raevschi,
• Serghei Cebotari,
• Marco Lux,
• Axel Haverich and
• Andres Hilfiker

Beilstein J. Nanotechnol. 2016, 7, 1330–1337, doi:10.3762/bjnano.7.124

• nanoparticles were synthesized on a sacrificial layer of zinc oxide (ZnO) nanoparticles using hydride vapor phase epitaxy. The uptake of GaN nanoparticles by porcine endothelial cells was strongly dependent upon whether they were fixed to the substrate surface or free floating in the medium. The endothelial

• cultivation process [19]. There is, however, limited knowledge about the biocompatibility of nanostructured GaN and the impact of GaN nanoparticles on living cells. Results GaN nanoparticles with diameters ranging from 50 to 100 nm were synthesized on a sacrificial layer of ZnO nanoparticles, as depicted in

• Figure 1. According to energy dispersive X-ray (EDX) measurements, approximately 2% of ZnO remained on the GaN nanoparticles after thermal treatment in hydrogen flow (Supporting Information File 1, Figure S1). The further removal of ZnO was not possible despite higher temperatures and longer incubation

Ammonia gas sensors based on In₂O₃/PANI hetero-nanofibers operating at room temperature

• Qingxin Nie,
• Zengyuan Pang,
• Hangyi Lu,
• Yibing Cai and
• Qufu Wei

Beilstein J. Nanotechnol. 2016, 7, 1312–1321, doi:10.3762/bjnano.7.122

• even death [5][6][7]. So, there is an urgent need to develop a kind of gas sensor with high sensitivity and selectivity to detect NH3 at room temperature. Metal oxide semiconductors can be applied as sensing materials for monitoring NH3. Ammonia sensors based on In2O3 [8], TiO2 [9], SnO2 [10], ZnO [11

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• conduction via the CNT. To date, numerous studies have been reported on the decoration of CNTs with metal oxides including TiO2 [7][8] and ZnO [9] for solar cell applications and SnO2 for gas sensors. Reports on the fabrication of an all carbon nanocomposite combining CNTs, graphene and carbon quantum dots

• including Hf and O vacancies [21]. The motivation of the present work is different from other well-studied luminescent nanocomposites containing TiO2 and ZnO that are investigated around band gap excitation. Here, contrary to the previous two semiconductors, novel optical properties and photocurrent

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• fabrication of titanium oxide nanowire (NW) gas sensors [25][26]. NO gas sensing at low concentrations is beneficial for human health [1][2] and environmental monitoring [3]. Various types of metal oxide nanomaterials have been utilized for NO or NO2 gas sensing, e.g., SnO2 [12][15][16][17], ZnO [13][14][17

Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers

• Kai Rückriem,
• Sarah Grotheer,
• Henning Vieker,
• Paul Penner,
• André Beyer,
• Armin Gölzhäuser and
• Petra Swiderek

Beilstein J. Nanotechnol. 2016, 7, 852–861, doi:10.3762/bjnano.7.77

• chemisorbed species, two possibilities arise. The first is a dissociative adsorption of CO2 on the copper nanoparticles that are formed under electron exposure. This process is important for the chemical understanding of the industrial methanol synthesis with Cu–ZnO–Al2O3 catalysts [48] and has been observed

Selective photocatalytic reduction of CO₂ to methanol in CuO-loaded NaTaO₃ nanocubes in isopropanol

• Tianyu Xiang,
• Feng Xin,
• Jingshuai Chen,
• Yuwen Wang,
• Xiaohong Yin and
• Xiao Shao

Beilstein J. Nanotechnol. 2016, 7, 776–783, doi:10.3762/bjnano.7.69

• can be solved simultaneously [3][4][5][6][7]. For this purpose, the photocatalytic conversion of CO2 to fuel is particularly emphasized. In 1979, Inoue et al. [8] first reported the photocatalytic reduction of CO2 in aqueous solution using several semiconductor materials (WO3, TiO2, ZnO, CdS, GaP and

Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

• Jacek Wojnarowicz,
• Roman Mukhovskyi,
• Elzbieta Pietrzykowska,
• Sylwia Kusnieruk,
• Jan Mizeracki and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2016, 7, 721–732, doi:10.3762/bjnano.7.64

• , morphology. The average particle size of Zn1−xMnxO was determined using Scherrer’s formula, the Nanopowder XRD Processor Demo web application and by converting the specific surface area results. X-ray diffraction of synthesized samples shows a single-phase wurtzite crystal structure of ZnO without any

• -doped zinc oxide nanoparticles; microwave solvothermal synthesis (MSS); characterization techniques of nanomaterials; physical properties of Mn2+-doped ZnO nanoparticles; Introduction Nanotechnology has triggered a new global industrial revolution of the 21st century [1]. At present it is the leading

• oxides semiconductors. Zinc oxide (ZnO) is a II–VI semiconductor characterised by a wide band gap of 3.3 eV and a high exciton binding energy of circa 60 meV [4]. ZnO is used in optoelectronic devices, solar cells, data carriers, light emitting diodes (LEDs), gas sensors, thermoelectric devices

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• - Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India, Research Services, University of Alberta, Edmonton, AB, Canada T6G2E1 10.3762/bjnano.7.44 Abstract Zinc oxide (ZnO) and bacteriorhodopsin (bR) hybrid nanostructures were fabricated by immobilizing bR on ZnO thin films and ZnO nanorods

• . The morphological and spectroscopic analysis of the hybrid structures confirmed the ZnO thin film/nanorod growth and functional properties of bR. The photoactivity results of the bR protein further corroborated the sustainability of its charge transport property and biological activity. When exposed

• to ethanol vapour (reducing gas) at low temperature (70 °C), the fabricated sensing elements showed a significant increase in resistivity, as opposed to the conventional n-type behaviour of bare ZnO nanostructures. This work opens up avenues towards the fabrication of low temperature, photoactivated

Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

Chemical bath deposition of textured and compact zinc oxide thin films on vinyl-terminated polystyrene brushes

• Nina J. Blumenstein,
• Caroline G. Hofmeister,
• Peter Lindemann,
• Cheng Huang,
• Johannes Baier,
• Andreas Leineweber,
• Stefan Walheim,
• Christof Wöll,
• Thomas Schimmel and
• Joachim Bill

Beilstein J. Nanotechnol. 2016, 7, 102–110, doi:10.3762/bjnano.7.12

• polystyrene brush on the deposition of ZnO thin films under moderate conditions. On a non-modified SiOx surface, island growth is observed, whereas the polymer brush induces homogeneous film growth. A chemical modification of the polystyrene brushes during the mineralization process occurs, which enables

• stronger interaction between the then polar template and polar ZnO crystallites in solution. This may lead to oriented attachment of the crystallites so that the observed (002) texture arises. Characterization of the templates and the resulting ZnO films were performed with ζ-potential and contact angle

• ; thin film growth; zinc oxide; Introduction Due to its promising properties like photoemission in the UV range and its high piezoelectric coefficient, zinc oxide (ZnO; space group P63mc) is interesting for a wide range of applications. Several research groups investigate its application in light

Dependence of lattice strain relaxation, absorbance, and sheet resistance on thickness in textured ZnO@B transparent conductive oxide for thin-film solar cell applications

• Kuang-Yang Kou,
• Yu-En Huang,
• Chien-Hsun Chen and
• Shih-Wei Feng

Beilstein J. Nanotechnol. 2016, 7, 75–80, doi:10.3762/bjnano.7.9

• Research Labs, Industrial Technology Research Institute, Hsinchu, Taiwan 10.3762/bjnano.7.9 Abstract The interplay of surface texture, strain relaxation, absorbance, grain size, and sheet resistance in textured, boron-doped ZnO (ZnO@B), transparent conductive oxide (TCO) materials of different thicknesses

• used for thin film, solar cell applications is investigated. The residual strain induced by the lattice mismatch and the difference in the thermal expansion coefficient for thicker ZnO@B is relaxed, leading to an increased surface texture, stronger absorbance, larger grain size, and lower sheet

• oxide; textured ZnO; Introduction Thin-film solar cells require a transparent conductive oxide (TCO) to allow light to reach the absorber layers and create the electrical current. Due to its superior characteristics, including a wide band gap, high dielectric constant, high exciton binding energy (60

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• stabilized gold nanoparticles (Au NPs) directly on the surface of nanostructured ZnO powders, previously synthesized through a sol–gel process. The effect of thermal annealing temperatures (300 and 550 °C) on chemical, morphological, and structural properties of pristine and Au-doped ZnO nancomposites (Au

• @ZnO) was investigated. Transmission and scanning electron microscopy (TEM and SEM), as well as X-ray photoelectron spectroscopy (XPS), revealed the successful deposition of nanoscale gold on the surface of spherical and rod-like ZnO nanostructures, obtained after annealing at 300 and 550 °C

• , respectively. The pristine ZnO and Au@ZnO nanocomposites are proposed as active layer in chemiresistive gas sensors for low-cost processing. Gas-sensing measurements towards NO2 were collected at 300 °C, evaluating not only the Au-doping effect, but also the influence of the different ZnO nanostructures on the

Sonochemical co-deposition of antibacterial nanoparticles and dyes on textiles

• Ilana Perelshtein,
• Anat Lipovsky,
• Nina Perkas,
• Tzanko Tzanov and
• Aharon Gedanken

Beilstein J. Nanotechnol. 2016, 7, 1–8, doi:10.3762/bjnano.7.1

• antibacterial CuO or ZnO nanoparticles (NPs) from an aqueous solution. The solution contains both the dye and the corresponding M(CH3COO)2 (M = Zn or Cu) precursor, which undergoes hydrolysis under alkaline conditions (ammonia) to form ZnO or CuO. The cotton was colored with the dye and showed good

• saline. The plates were allowed to grow overnight at 37 °C and the viable bacteria were counted thereafter. Results and Discussions Optimization of the co-deposition The deposition of the two compounds, the antibacterial ZnO or CuO, and the RO16 or RB5 dyes were carried out by dissolving the

• textile surface where they remain strongly embedded. Indeed, the XRD patterns of the fabric at the end of the reaction revealed the formation of MO NPs on the surface (Figure 1). The XRD pattern of the sonochemically prepared ZnO NPs correspond to hexagonal phase of zincite (Figure 1a). The peaks at 2θ

Blue and white light emission from zinc oxide nanoforests

• Nafisa Noor,
• Luca Lucera,
• Thomas Capuano,
• Venkata Manthina,
• Alexander G. Agrios,
• Helena Silva and
• Ali Gokirmak

Beilstein J. Nanotechnol. 2015, 6, 2463–2469, doi:10.3762/bjnano.6.255

• , University of Connecticut, Storrs, Connecticut 06269, USA 10.3762/bjnano.6.255 Abstract Blue and white light emission is observed when high voltage stress is applied using micrometer-separated tungsten probes across a nanoforest formed of ZnO nanorods. The optical spectrum of the emitted light consistently

• electrical contact with the ZnO structures melt during the excitation, indicating that the local temperature can exceed 3422 °C, which is the melting temperature of tungsten. The distinct and narrow peaks in the optical spectra and the abrupt increase in current at high electric fields suggest that a plasma

• also arise from the recombination through multiple defect levels in ZnO or due to the optical excitation from solid ZnO. The electrical measurements performed at different ambient pressures result in light emission with distinguishable differences in the emission properties and I–V curves, which also