Nm For Films Research Articles

Cavitation behavior of poly(4‐methyl‐1‐pentene)/polypropylene/poly(4‐methyl‐1‐pentene) tri‐layer film: Influence of annealing and stretching temperature

AbstractIn this work, poly(4‐methyl‐1‐pentene)/polypropylene/poly(4‐methyl‐1‐pentene) tri‐layer films were prepared. The microstructure of the film was adjusted by annealing in the temperature range of 150–237.5°C. Afterward, the influence of annealing and stretching temperature on the cavitation behavior of the film was investigated by small‐angle x‐ray scattering (SAXS). Results showed that for the “butterfly” scattering in the early stage, the radius of gyration () and maximum dimension () of voids were ca. 75 and 200 nm, which were hardly influenced by annealing. Whereas, the volume fraction of voids was enlarged obviously, suggesting that more voids were formed; for the “streak” scattering in the late stage, the length of voids () grew gradually with stretching, and the ultimate value of was 432.5 nm for un‐annealed film and 176 nm for film annealed at 230°C. Simultaneously, the misorientation of voids was reduced from 0.33 to 0.18. As the stretching temperature was elevated from 30 to 45 and 60°C, and maintained at 75 and 200 nm, and was enlarged to 434 and 432 nm. At the same time, the number of voids was reduced obviously. As the stretching temperature was 90°C, the voids were suppressed.

Optoelectronic properties of BiCuOSe p-type oxychalcogenides

BiCuOSe systems are proposed as candidates to develop transparent p-type semiconductors in the visible region. This work reports the characterization results obtained for the BiCuOSe powders, synthesized by the solid-state reaction (SSR) method through mechanical milling, and nanostructured thin films deposited from the same processed powders using the pulsed laser deposition (PLD) technique. Structural characterization through X-ray diffraction (XRD) showed that the material presents a tetragonal structure with an average crystallite size of 21 nm and a preferential orientation in the (1 0 2) plane. The morphological and particle size evolution of BiCuOSe powders is presented as a function of the milling time. Transmission and scanning electron microscopies confirmed the spherical geometry of the particles in the powders and nanosheets like structure for the films. Particle sizes were also estimated, ranging from 10 to 100 nm for powders and 60 to 70 nm for films. The bandgap values, EG, for BiCuOSe powders were estimated from diffuse reflectance spectra using the Kubelka–Munk method, yielding values close to 0.7 eV. For thin films, EG values were estimated using the Tauc method, obtaining values in the range of 0.8–3.5 eV, depending on the annealing treatment. Additionally, electrical properties were measured in all deposited thin films, confirming the p-type conductivity, a minimal resistivity of 0.0735 Ω cm, hole mobility on the order of 88 cm2/Vs, and carrier concentration of 9.7 × 1018 cm−3.

Ni doping induced property enhancement in laser ablated BaSnO3 films suitable for optoelectronic applications

Pulsed laser deposition is a straightforward approach for preparing films with superconducting to dielectric properties with atomic layer precision. The deep-seated mechanisms involved in the particle transport from target to substrate and subsequent film formation still need to be fully comprehended. This manuscript reports the property enhancement observed in laser ablated perovskite BaSnO3 films with Ni doping. Films' crystallinity improvement is observed, and an intensity enhancement of 1150% is observed on 3 mol% Ni-doping. The optimum Ni-doping concentration in BaSnO3 is found to be 3 mol%. Herein, Ni-doped BaSnO3 films deposited by PLD showed an unusual increase in film thickness (i.e., from 615 nm in the pure film to 1317 nm in the film with 7 mol% Ni-doping as revealed by lateral SEM analysis and spectroscopic ellipsometry). We propose an “Induced Magnetic field-assisted Particle Convergence (IMPC)” effect for this superficial growth enhancement. The film's optical properties are modified with an increased nickel doping level, and the bandgap energy shows renormalization. All the films show excellent transmittance (80–90%) in the Vis.-NIR region. Hall-effect measurement reveals the increased carrier concentration by three orders (2.98 × 1011 to 3.50 × 1014 cm−3). In addition, the enhancement in mobility from 3.13 to 20.93 cm2V−1s−1 and a decrease in electrical resistivity by six orders (i.e., from 4.05 × 109 to 1.13 × 103 Ω cm) are observed on 7 mol% Ni doping. XPS measurements reveals that the Ba, Sn and Ni ions are at 2+, 4+ and 2+ oxidation states. Using spectroscopic ellipsometric method, we estimated the optical constants of the films, the refractive index, dielectric constant, and extinction coefficient show a normal dispersion behavior. The high crystallinity, high transmittance, suitable surface topography, and improved electrical performances of the Ni-doped BaSnO3 films make them excellent candidates for optoelectronic devices and solar cells.

Optical and electric characteristics of CuO nanoparticle-doped ZnO thin films using thermionic vacuum arc deposition system

In this study, the thermionic vacuum arc (TVA) method was employed to fabricate thin films of zinc oxide (ZnO) doped with copper oxide nanoparticles (CuONPs). The primary objective was to investigate the influence of the substrate on the characteristics of the CuONPs-doped ZnO thin films. CuONPs were synthesized using both the solution plasma process and the high-voltage liquid plasma generation method, resulting in particle sizes ranging from 20 to 40 nm. The X-ray diffraction (XRD) pattern confirmed the polycrystalline nature of the CuONPs. The prepared CuONPs in powder form were blended with ZnO powder and utilized as an anode material for TVA discharge and coating. The structural, optical, elemental, and topological properties of the resulting thin films were systematically examined. The findings revealed that the deposited thin films exhibited a polycrystalline structure, with transparent and electrically conductive layers. Similar reflection values were observed for films deposited on both glass and indium tin oxide (ITO)-coated glass substrates. Nanostructures on the film surfaces were elucidated through field emission scanning electron microscopy images. The atomic ratios of Cu/Zn were determined as 1/3 and 1/10 for films deposited on uncoated and ITO-coated glass substrates, respectively. The mean grain size of the nanoparticles on the film surface measured approximately 17 nm for films deposited on uncoated glass substrates and 35 nm for those deposited on ITO-coated glass substrates. The film resistance was measured at 20 kΩ, indicating its suitability as a semiconductor. Analysis of the XRD pattern identified peaks corresponding to CuONPs and ZnO in the deposited films, affirming their polycrystalline nature. In conclusion, the deposited thin films exhibit favorable characteristics for semiconductor applications, and the coating method employed proves to be effective in producing high-quality thin films.

Crystal growth, optical, photoluminescence and magnetic properties of sol-gel GdFeO3 thin film

GdFeO3 (GFO) orthoferrite is a perovskite structured material with rich physical properties. In this work, crystal growth, electronic, optical, photoluminescence (PL) and magnetic properties of sol-gel synthesized GFO thin films onto quartz substrate were investigated. The films were annealed at various temperature 650–900 °C. XRD results showed transformation from an amorphous to nanocrystalline GFO and GdO secondary phase with rise of annealing temperature from 650 to 700 °C. Single phase GFO was observed in films annealed above 700 °C. Crystallite size of the films gradually increased from 10.5 to 89.9 nm for films annealed from 700 to 900 °C, respectively. The surface morphology changed from porous microstructure consisted of tiny particulates in film annealed at 700 °C into enlarged particles and clear polycrystalline structure in films annealed above 700 °C. From XPS spectra analysis, both Fe and Gd ions existed in a 3+ valence state. The films demonstrated optical band gap ranged between 2.8 and 3 eV. The PL spectra obtained using a 300 nm excitation wavelength consisted of four emission peaks. The near band edge emission of the films varied between 449.9 and 455.1 nm. The films showed weak ferromagnetic behavior with magnetization ranging from 24 to 49 emu/cm3.

Asymmetric Fluorene‐Based Fused‐Ring Molecules Acceptors for Fullerene‐Free Organic Solar Cells

Asymmetric fluorene‐based fused‐ring molecules acceptors 2,2′‐((2Z,2′Z)‐(((11,11‐dioctyl‐5,5‐dioxido‐11H‐benzo[b]fluoreno[2,3‐d]thiophene‐3,9‐diyl)bis(3‐octylthiophene‐5,2‐diyl))‐bis(methaneylylidene))bis(3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile [BTOFIC] and 2,2′‐((2Z,2′Z)‐((5,5′‐(11,11‐dioctyl‐11H‐benzo[b]fluoreno[2,3‐d]thiophene‐3,9‐diyl)bis(3‐octylthiophene‐5,2‐diyl))bis(methanylylidene))‐bis(3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diyl‐idene))dimalononitrile [BTFIC] are synthesized. BTOFIC and BTFIC are easily soluble in common organic solvents. The highest occupied molecular orbital energy levels, the lowest unoccupied molecular orbital energy levels, and the bandgaps (Egs) of BTOFIC and BTFIC are −5.91, −3.87, and 2.04 eV and −5.72, −3.81, and 1.91 eV, respectively. BTOFIC and BTFIC show the maximum absorption peak (λmax) at 548 and 648 nm and a strong shoulder peak at 592 and 576 nm in film, and the optical bandgaps of 1.87 and 1.81 eV, respectively. The organic solar cells (OSCs) fabricated with poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)] [PTB7‐Th]:BTOFIC and PTB7‐Th:BTFIC show a power conversion efficiency of 3.31% and 5.35%, respectively. In this research, it is revealed that BTOFIC and BTFIC can be potential asymmetric non‐fullerene acceptors for further development of OSCs.

Nanostructure, optical, electronic, photoluminescence and magnetic properties of Co-doped ZrO2 sol–gel films

ZrO2 is a fascinating metal oxide with rich physical phenomenon and promised applications. In this study, the effects of chemical doping with Co+2 ions on nanostructure, electronic, optical, photoluminescence (PL), and magnetic properties of Zr1-xCoxO2 thin films (x = 0.0, 0.05, 0.1, and 0.15) prepared by sol–gel spin-coating method were investigated. The films exhibited a tetragonal structure with crystallinity improved with Co doping. Pure ZrO2 film showed a smooth surface morphology consisting of small particle size of 22 nm. The Co-doped ZrO2 films exhibited well-ordered holes, and their size and number increased with Co doping up to x = 0.1 and then decreased at x = 0.15. Root-mean-square roughness increased from 1.1 nm for pure ZrO2 to 16.5 nm for film x = 0.15. The Co ions in the films existed in a 2 + valence state. Energy band gap decreased with Co doping and had values of 4.40, 4.396, 4.392, and 4.170 eV for the films with x = 0.0, 0.05, 0.1, and 0.15, respectively. The PL spectra of films x = 0.00 and 0.05 are mainly comprised of two emission peaks; intense peak centred at 370 nm and broad peak centred about 500 nm. As the Co concentration increased, two intense and sharp emission peaks emerged at 335 and 373 nm. The films showed soft hysteresis loop, and their magnetization was enhanced with the increase of Co content.

Effect of annealing onto physical properties of Co:ZnO thin films prepared by spray pyrolysis technique

In this work, the effect of annealing on the physical properties of Co-doped ZnO thin films has been explored. The Co doping level was fixed at 10 weight (wt) % and deposition has been performed using spray pyrolysis techniques. The deposited film was annealed at temperatures of 400, 450, and 500 °C under an air stream of 5 L min−1. The effect of annealing on the physical properties of the deposited film was investigated using x-ray diffraction (XRD), scanning electron microscope(SEM), x-ray dispersive spectroscopy (EDX), x-ray photoelectron spectroscopy (XPS), and optical spectroscopy. XRD results revealed the formation of a single-phase ZnO thin film with no other phases even after annealing. The estimated crystallite size was found to be 34 nm for the un-annealed film which was reduced to 31 nm for film annealed at 400 °C. The SEM images show the formation of large grains which respond differently to the annealing process. Upon annealing the band gap value shows a reduction and the plasma fRequency shows an increase. The performance of all films as UV sensors shows the reduction in the response time for film annealed at 400 °C and the decay time, at the same voltage, for film annealed at 450 °C.

High- and low-temperature resistant and intrinsically flame retardant poly(bisphthalazinone thioether sulfone ketone)s: Synthesis, structures and properties

High-performance polymers that are both high temperature resistant and soluble is significant for the development of high-tech fields. 4,4′-(Thiobis(4,1-phenylene))bis(phthalazin-1(2H)-one) (T-BDHPZ) monomer is synthesized by an efficient two-step method using inexpensive phenyl sulfide and phthalic anhydride as raw materials. A series of novel poly(bisphthalazinone thioether sulfone ketone)s (PBPTSKs) were synthesized via aromatic nucleophilic substitution polycondensation. The structures of PBPTSKs were characterized by NMR and FT-IR. These polymers have glass transition temperatures (Tgs) in the range of 302–328 ℃, and are soluble in N-methyl-2-pyrrolidone (NMP), pyridine (Py) and 1,1,2,2-tetrachloroethane (TECT), and partially soluble in N,N -dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dichloromethane (DCM), trichloromethane (TCM) and pyridine. PBPTSK films were prepared by solution casting, and the average light transmittance from 400 to 800 nm of films are all over 70%. PBPTSK boards prepared by hot press molding have outstanding mechanical properties with the tensile strength and the flexural strength of 91–102 MPa and 123–135 MPa, respectively. PBPTSK boards also exhibit excellent high- and low-temperature resistance properties at 290 and −60c, respectively. Moreover, these polymers with bisphthalazinone thioether moiety have outstanding inherent flame retardancy, which pass the V-0 level of the UL-94 test. This provides opportunities to develop high-performance polymers that are both high temperature resistant and soluble, showing great prospects in frontier applications.

Highly rigid and functional poly(benzimidazole sulfone)s from 5,6‐dimethoxy‐1,3‐dihydro‐2H‐benzo[d]imidazol‐2‐one monomer

AbstractA series of poly(benzimidazole sulfone)s (PBSs) and poly(benzimidazole ketone)s (PBKs) containing 5,6‐dimethoxy‐1,3‐dihydro‐2H‐benzo[d]imidazol‐2‐one (MBIO) have been synthesized by C–N/C–O coupling with different percentages of three other diphenol monomers under similar conditions. The structure of PBS‐MBs and PBK‐MBs was confirmed using 1H NMR and Fourier transform infrared spectroscopies, and X‐ray diffraction data revealed that all the polymers are in an amorphous state. Due to the introduction of methoxy, the polymers were more soluble in common aprotic polar solvents. The intrinsic viscosity of the synthesized polymers was measured with an Ubbelohde viscometer, ranging from 0.38 to 1.35 dL g−1. The MBIO‐based polymers have a remarkably good thermal stability with a high glass transition temperature of up to 305.1 °C. Furthermore, the wavelength of maximum fluorescence emission from homopolymers is around 414 nm with emission of blue light in N‐methyl‐2‐pyrrolidone solution (1 mg L−1) and around 530 nm in films. They also showed low dielectric constants (κ = 2.60–3.10 at 1 MHz) and low water absorption (0.22–0.58%). It was encouraging to discover that these polymers have potential utility for the microelectronics industry, in which good solubility facilitates processing and molding, excellent thermal stability allows devices to be used under harsh conditions, low water absorption prevents device expansion and shrinkage and low dielectric constant is desired to prevent crosstalk between conducting paths. © 2023 Society of Industrial Chemistry.

New Non-Fullerene Acceptor with Extended Conjugation of Cyclopenta [2,1-b:3,4-b'] Dithiophene for Organic Solar Cells.

Herein, we design and characterize 9-heterocyclic ring non-fullerene acceptors (NFAs) with the extended backbone of indacenodithiophene by cyclopenta [2,1-b:3,4-b'] dithiophene (CPDT). The planar conjugated CPDT donor enhances absorption by reducing vibronic transition and charge transport. Developed NFAs with different end groups shows maximum absorption at approximately 790-850 nm in film. Because of the electronegative nature of the end-group, the corresponding acceptors showed deeper LUMO energy levels and red-shifted ultraviolet absorption. We investigate the crystallinity, film morphology, surface energy, and electronic as well as photovoltaic performance. The organic photovoltaic cells using novel NFAs with the halogen end groups fluorine or chlorine demonstrate better charge collection and faster exciton dissociation than photovoltaic cells using NFAs with methyl or lacking a substituent. Photovoltaic devices constructed from m-Me-ITIC with various end groups deliver power conversion efficiencies of 3.6-11.8%.

Design, synthesis and properties of a new near-infrared small molecule acceptor for organic photodetector

Recently, organic photodetectors (OPDs) have occupied a crucial position in the photoelectric industry due to their low cost and convenient production. For its potential applications in near-infrared (NIR) wavelengths, NIR-OPDs with high responsivity and detectivity have attracted a lot of research interest. In this manuscript, we designed and synthesized a new n-type semiconductor, TPBT-OR, by introducing alkoxythiophene into Y5. TPBT-OR exhibits a small optical bandgap of 1.20 eV and red-shifted absorption peaks of 882 nm in film. Using P3HT as a donor and without much additional treatment in device, broad spectra response over 10 11 Jones (cm Hz 1/2 W −1 ) can be achieved in the wavelength of 320 nm–1000 nm with the maximum responsivity of 0.084 A W −1 and detectivity of 7.87 × 10 11 Jones at around 850 nm. Thus, the new TPBT-OR molecule is a promising non-fullerene acceptor in near-ultraviolet to near-infrared detection. • A new ‘A-π-DAD-π-A’ type non-fullerene semiconductor TPBT-OR has been designed and synthesized. • Compared with Y5, it demonstrates a significantly upshifted E HOMO , a slightly downshifted E LUMO , and thus a low optical bandgap of 1.20 eV. • Organic photodetector based on P3HT:TPBT-OR exhibit panchromatic detection between the wavelength of 320 nm and 1000 nm.

Impact of Star Polyacid Branching on Polymer Diffusion within Multilayer Films

A series of linear and star poly(acrylic acids) (LPAA and star PAAs) were synthesized to explore the effect of molecular architecture on the stratification and polymer dynamics of electrostatic layer-by-layer (LbL) films. Studies of LbL deposition of LPAA and star PAAs with poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) at acidic pH showed an ∼30% increase in film dry thickness with increased polymer branching. Consistent with a greater mass of star polymer deposited within the films, in situ ellipsometric measurements of PAA uptake from solution revealed ∼3.5-fold greater diffusion coefficients for 8-arm PAA in comparison to linear PAA. For comparison, the dynamics of the linear PDMAEMA partner was explored via neutron reflectometry (NR) studies of stacked multilayers containing hydrogenated and deuterated polycations, hPDMAEMA and dPDMAEMA. The stacked multilayers deposited from low-ionic-strength solutions were stratified, exhibiting interfacial widths between hydrogenated and deuterated stacks of ∼15 and 10 nm for films constructed with star and linear PAAs, respectively, suggesting relatively low mobility of the polycation in both assemblies. Further exposure of these films to 0.5 M sodium chloride solutions enhanced the mobility of PDMAEMA, revealing an order magnitude faster diffusion of PDMAEMA in films of 8-arm PAA relative to linear PAA. The faster diffusion of polymers within films of star polyacids was correlated not only with the compactness of star polymers but also with an ∼2-fold lower ionization of assembled 8-arm PAA as determined by Fourier transform infrared spectroscopy and thus a lower number of polycation–polyacid ionic contacts in the case of star polymers as compared to their linear counterparts. The significant influence of molecular architecture on the number of polymer–polymer contacts was further confirmed by isothermal titration calorimetry studies of polyelectrolyte complexes in solution.

Surface Morphology and Structure in ZnO films doped with Ga and In impurities

The ZnO:Ga:In nanocrystal (NC) films co-doped with Ga and In donor type impurities have been investigated The films were produced by spray pyrolysis ultrasonic on Si substrates kept at 400°C. The group of samples was grown with permanent In content of 1at% in the films, and with various Ga contents of 0.5 at% up to 2.5 at% Ga. All samples for better crystallization have been further annealed in a nitrogen flow (5 L/min) at 400°C during 4h.The non-monotonous varying the surface morphology has been detected in ZnO:Ga:In NC films. With a small Ga content (≤1.0 at%) and a high Ga content (≥2.0 at%), the grains have the form of small sheets distributed randomly on the surface. The sheet like shape changes to nanorod with hexagonal cross sections of the size 50-100 nm in films with 1.5 at% Ga. With all Ga concentrations the ZnO films studied demonstrated the crystal structures of wurtzite. However, the XRD peak positions and ZnO lattice parameters change non monotonically versus Ga contents. The factors that favor the non-monotonic change of the parameters of the ZnO crystal lattice have been analysed. The Ga/In doping concentrations necessary to obtain ZnO films with low roughness and flat surface morphology have been estimated.

Synergetic Insulation and Induction Effects Selectively Optimize Multiresonance Thermally Activated Delayed Fluorescence.

Multiresonance (MR) emitters featuring narrowband emissions and theoretically 100% exciton harvesting are great potential for organic light-emitting diode (OLED) applications. However, how to functionalize MR molecules without scarifying emission color purity is still a key challenge. Herein, we report a feasible strategy for selective optimization of MR molecules, which is demonstrated by a blue MR emitter tCBNDASPO substituted with a diphenylphosphine oxide (DPPO) group. Compared to its DPPO-free parent molecule, tCBNDASPO preserves narrowband feature with full widths at half maximum (FWHM) values of 28 nm in film and 32 nm in OLEDs and achieves 40% increased photoluminescence (92%) and electroluminescence quantum efficiencies (28%). It is showed that insulation effect of P=O effectively confines the singlet excited state on MR core to keep emission color purity, and its induction effect enhances singlet radiation and triplet-to-singlet conversion. This synergism for selective optimization is based on rational linkage between MR core and functional groups.

Thickness mod ulated structural and photo-luminescence properties of magnetron sputtered nanocrystalline SiC ultrathin films

Ultrathin silicon carbide (SiC) films were grown on p type Si (100) substrate by RF magnetron sputtering at constant substrate temperature of 7000C for investigating thickness dependence of structural and photoluminescence properties. The structural and Photoluminescence properties were measured by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and photospectrometer respectively. X-ray diffraction pattern revealed (102) and dominant (105) reflections which corresponds to 4H-SiC and an enhancement in (105) peak intensity with increasing thickness was also observed. The thickness measured by X-ray reflectometry (XRR) reduces from ~ 46 nm to 12 nm by decreasing deposition time (40-10 minute) which in turn reduces the crystallite size. Photoluminescence spectra show a broad peak extending from ultraviolet to blue region centered at ~ 385 nm for film of thickness ~ 46 nm (deposition time 40 min). A shifting in Photoluminescence peak towards shorter wavelength (blue shift) with decreasing SiC ultrathin film thickness was observed, which could be attributed to quantum confinement effect. The improved Photoluminescence in ultrathin nanocrystalline SiC films could make it a potential candidate in optoelectronic and biomedical applications. Copyright © 2017 VBRI Press.

Morphological and mechanical evolution of nanostructured ZrN thin films under 165 keV argon ions irradiation

Zirconium nitride is a promising candidate ceramic material to be adopted as an inert matrix for transuranic fuel, a new fuel concept having as targets the closing of the nuclear fuel cycle, and reduce the environmental impact of nuclear waste. Nevertheless, the comprehension of radiation tolerance of zirconium nitride still limited. In this paper, we have studied the radiation stability of nanostructured zirconium nitride (ZrN) thin films using 165 keV argon-ions (Ar2+) irradiation at room temperature. After irradiation, the microstructural, morphological and mechanical properties of the irradiated ZrN films were investigated and compared to an un-irradiated reference film. The grazing incidence X-ray diffraction tests (GI-XRD) revealed a (100) ZrN textured films, the atomic force microscope (AFM) and the scanning electron microscope (SEM) images showed that the as-deposited ZrN films were nano-crystalline with spherical grains of about 50 nm in size and rms surface roughness of about 1.175 nm. After irradiation, the estimate grains size was found to increase to 72 and 86 nm for films irradiated to 2.3 and 22.3 (dpa) respectively, indicating grains coalescence. The nano-hardness of the irradiated films compared to the un-irradiated film was decreased for both doses, while the XRD patterns demonstrate a crystalline ZrN even at the higher dose of 22.3 (dpa), suggesting along with AFM and SEM results grain growth without amorphisation.

Annealing Studies of Copper Indium Oxide (Cu2In2O5) Thin Films Prepared by RF Magnetron Sputtering

Copper indium oxide (Cu2In2O5) thin films were deposited by the RF magnetron sputtering technique using a Cu2O:In2O3 target. The films were deposited on glass and quartz substrates at room temperature. The films were subsequently annealed at temperatures ranging from 100 to 900 °C in an O2 atmosphere. The X-ray diffraction (XRD) analysis performed on the samples identified the presence of Cu2In2O5 phases along with CuInO2 or In2O3 for the films annealed above 500 °C. An increase in grain size was identified with the increase in annealing temperatures from the XRD analysis. The grain sizes were calculated to vary between 10 and 27 nm in films annealed between 500 and 900 °C. A morphological study performed using SEM further confirmed the crystallization and the grain growth with increasing annealing temperatures. All films displayed high optical transmission of more than 70% in the wavelength region of 500–800 nm. Optical studies carried out on the films indicated a small bandgap change in the range of 3.4–3.6 eV during annealing.

Simple peripheral modification for color tuning of thermally activated delayed fluorescence emitters in OLEDs

Through simple peripheral tert-butyl or methoxy substitution at 3,6-position of carbazole to increase electron donating property, emission colors of donor-acceptor (D-A) type thermally activated delayed fluorescence (TADF) emitters are rationally tuned. Due to enhanced intramolecular D-A interactions, the intramolecular charge transfer (ICT) transition absorption is bathochromically shifted from 451 to 474 and 490 nm in DCM solution and 458 to 476 and 497 nm in film for 4CzCNPy, 4tCzCNPy and 4oCzCNPy, respectively. And the singlet, triplet as well as HOMO energy levels were also gradually down-shifted from bare 4CzCNPy to 4tCzCNPy and 4oCzCNPy. 4CzCNPy shows green emission in DCM, while 4tCzCNPy and 4oCzCNPy demonstrates yellow and deep red, with peak values from 536 to 561 and 634 nm, respectively. TADF OLEDs based on yellow emitter of 4tCzCNPy exhibit a maximum external quantum efficiency (EQE) of 22.2%, while maximum EQE of 17% and 2.9% is achieved for the green 4CzCNPy and orange-red 4oCzCNPy.

Atomic layer deposition of sodium fluoride thin films

The need for advanced energy conversion and storage devices remains a critical challenge amid the growing worldwide demand for renewable energy. Metal fluoride thin films are of great interest for applications in lithium-ion and emerging rechargeable battery technologies, particularly for enhancing the stability of the electrode-electrolyte interface and thereby extending battery cyclability and lifetime. Reported within, sodium fluoride (NaF) thin films were synthesized via atomic layer deposition. NaF growth experiments were carried out at reactor temperatures between 175 and 250 °C using sodium tert-butoxide and HF-pyridine solution. The optimal deposition temperature range was 175–200 °C, and the resulting NaF films exhibited low roughness (Rq ≈ 1.6 nm for films of ∼8.5 nm), nearly stoichiometric composition (Na:F = 1:1.05) and a growth per cycle value of 0.85 Å/cycle on SiO2 substrates. These results are encouraging for future applications of NaF thin films in the development of improved energy capture and storage technologies.