Vacuum Deposition Techniques Research Articles

Light management in Cu2ZnSnSe4 solar cells with ZnO:Al periodic sub-wavelength architectures

This study used a vacuum deposition technique to manufacture Cu₂ZnSnSe₄ (CZTSe) solar cells, providing a scalable and safe manufacturing approach for low-cost, high-performance photovoltaic technology. Additionally, nanoimprint lithography was successfully employed to fabricate two types of periodic sub-wavelength architectures on the surface of CZTSe solar cells, serving as anti-reflective layers and further enhancing their conversion efficiency. The research demonstrates that when the surface architecture of the CZTSe solar cells is Nano-hill, it exhibits superior gradient refractive index and optimal anti-reflective properties, consistent with simulation results. For CZTSe solar cells with this surface architecture, the average reflectance decreased from the pristine 9.86 %–7.34 %, and at an incident light angle of 60°, the reflectance dropped from 17.99 % to 9.53 %, demonstrating the architecture's omnidirectional anti-reflective capability. The periodic sub-wavelength architectures fabricated in this study enhanced the efficiency of the solar cells from 3.68 % to 6.66 %, not only improving conversion efficiency but also showcasing the potential for comprehensive anti-reflective layers, interface repair, and continuous processing. This research not only contributes to optical design but also holds significant importance for the future development of CZTS(Se) technology.

Fabrication of Anode Functional Layer By Reactive Sputtering for Large Area Thin-Film Solid Oxide Cells

Solid Oxide Cells (SOCs), the electrochemical device that converts chemical to electrical energy, or electrical to chemical energy, have been highlighted for its high efficiency, fuel flexibility, and reversible operation modes between fuel cells and electrolyzers. Recent research has focused on developing intermediate-temperature SOCs (operating between 500 ~ 700°C) to address issues such as thermal durability, and cost. However, reducing the operating temperature presents challenges including decreased rates of charge and ion transport. Consequently, fabricating thin-film SOCs (TF-SOCs) constructed on porous anode supports helps maintain adequate power density even at lower temperatures.Traditional anode supports, however, present limitations in fabricating thin electrolytes due to their rough surface topographies and large pore structures, inherent to powder-based processing methods. To overcome these challenges, vacuum deposition techniques have emerged as alternatives, offering precise control over micro to nanostructures. This precise control enables the smoother layer, referred to as anode functional layers (AFLs), characterized by finer grain sizes. The fabrication of nanostructured AFLs (n-AFLs) enhances the triple-phase boundary (TPB) length, charge transfer, and overall electrochemical kinetics of the cell.Despite these advancements, scalability remains a critical problem that prevents the commercialization of SOCs with optimized AFLs. One of the physical vapor deposition techniques, sputtering, attracts attention due to its scalability, reproducibility, and compatibility with multilayered designs. Reactive sputtering allows the deposition of composite materials by introducing reactive gases during the deposition process.In this study, we fabricated a large-area (12cm x 12cm) n-AFL featuring nano-sized grains via reactive sputtering. A thermal treatment at 1200°C was followed to ensure the structural integrity and stability. By optimizing sputtering power and oxygen partial pressure, we successfully suppress pore and crack formation and Ni agglomeration during the post-annealing, resulting in a durable AFL with enhanced performance characteristics.The optimized AFL, fabricated under 3kW sputtering power and 80% oxygen partial pressure, effectively mitigates structural defects induced by the thermal process. Consequently, TF-SOCs with n-AFL exhibit impressive performance in fuel cell mode, achieving power densities of 1286mW/cm2 at 650°C and 912mW/cm2 at 600°C. In contrast, cells without the n-AFL show low open-circuit voltages (OCV) of below 0.8V. It is speculated that the gas crossover is due to the pores generated from the heat treatment.

Ultrathin Triple Conducting Oxide Interlayer for Protonic Ceramic Electrochemical Cells Fabricated by Chemical Solution Deposition

Protonic ceramic electrochemical cells (PCECs) offer the capability to enhance electrochemical properties across various energy conversion systems, efficiently transforming chemical fuels into electricity and vice versa, operating at temperatures below 600 °C. However, poor contact between the oxygen electrode, which possesses triple conductivity (H+/O2-/e-), and the electrolyte results in elevated ohmic resistance, impeding the electrochemical reactions of PCECs. To improve the adhesion between the oxygen electrode and the electrolyte layer, various vacuum deposition techniques such as pulsed laser deposition and atomic layer deposition have been proposed for thin-film interlayer fabrication. Nonetheless, the high cost, intricate procedures, and scalability challenges associated with vacuum-based processes may render them unsuitable for industrial applications. Herein, we present a straightforward method for depositing an ultrathin triple-conducting oxide interlayer using the chemical solution deposition technique. This thin interlayer was effectively deposited between the electrolyte and the oxygen electrode layer, leading to a decrease in ohmic resistance and showcasing the enhanced performance of PCECs. Our results provide valuable insights into overcoming the current challenges encountered by PCECs and highlight the potential for large-scale system applications.

Physico-Chemical Properties of Copper-Doped Hydroxyapatite Coatings Obtained by Vacuum Deposition Technique.

The hydroxyapatite and copper-doped hydroxyapatite coatings (Ca10-xCux(PO4)6(OH)2; xCu = 0, 0.03; HAp and 3CuHAp) were obtained by the vacuum deposition technique. Then, both coatings were analyzed by the X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and water contact angle techniques. Information regarding the in vitro antibacterial activity and biological evaluation were obtained. The XRD studies confirmed that the obtained thin films consist of a single phase associated with hydroxyapatite (HAp). The obtained 2D and 3D SEM images did not show cracks or other types of surface defects. The FTIR studies' results proved the presence of vibrational bands characteristic of the hydroxyapatite structure in the studied coating. Moreover, information regarding the HAp and 3CuHAp surface wettability was obtained by water contact angle measurements. The biocompatibility of the HAp and 3CuHAp coatings was evaluated using the HeLa and MG63 cell lines. The cytotoxicity evaluation of the coatings was performed by assessing the cell viability through the MTT assay after incubation with the HAp and 3CuHAp coatings for 24, 48, and 72 h. The results proved that the 3CuHAp coatings exhibited good biocompatible activity for all the tested intervals. The ability of Pseudomonas aeruginosa 27853 ATCC (P. aeruginosa) cells to adhere to and develop on the surface of the HAp and 3CuHAp coatings was investigated using AFM studies. The AFM studies revealed that the 3CuHAp coatings inhibited the formation of P. aeruginosa biofilms. The AFM data indicated that P. aeruginosa's attachment and development on the 3CuHAp coatings were significantly inhibited within the first 24 h. Both the 2D and 3D topographies showed a rapid decrease in attached bacterial cells over time, with a significant reduction observed after 72 h of exposure. Our studies suggest that 3CuHAp coatings could be suitable candidates for biomedical uses such as the development of new antimicrobial agents.

Unfolding the Challenges To Prepare Single Crystalline Complex Oxide Membranes by Solution Processing.

The ability to prepare single crystalline complex oxide freestanding membranes has opened a new playground to access new phases and functionalities not available when they are epitaxially bound to the substrates. The water-soluble Sr3Al2O6 (SAO) sacrificial layer approach has proven to be one of the most promising pathways to prepare a wide variety of single crystalline complex oxide membranes, typically by high vacuum deposition techniques. Here, we present solution processing, also named chemical solution deposition (CSD), as a cost-effective alternative deposition technique to prepare freestanding membranes identifying the main processing challenges and how to overcome them. In particular, we compare three different strategies based on interface and cation engineering to prepare CSD (00l)-oriented BiFeO3 (BFO) membranes. First, BFO is deposited directly on SAO but forms a nanocomposite of Sr-Al-O rich nanoparticles embedded in an epitaxial BFO matrix because the Sr-O bonds react with the solvents of the BFO precursor solution. Second, the incorporation of a pulsed laser deposited La0.7Sr0.3MnO3 (LSMO) buffer layer on SAO prior to the BFO deposition prevents the massive interface reaction and subsequent formation of a nanocomposite but migration of cations from the upper layers to SAO occurs, making the sacrificial layer insoluble in water and withholding the membrane release. Finally, in the third scenario, a combination of LSMO with a more robust sacrificial layer composition, SrCa2Al2O6 (SC2AO), offers an ideal building block to obtain (001)-oriented BFO/LSMO bilayer membranes with a high-quality interface that can be successfully transferred to both flexible and rigid host substrates. Ferroelectric fingerprints are identified in the BFO film prior and after membrane release. These results show the feasibility to use CSD as alternative deposition technique to prepare single crystalline complex oxide membranes widening the range of available phases and functionalities for next-generation electronic devices.

Epitaxial Growth of Large-Area Monolayers and van der Waals Heterostructures of Transition-Metal Chalcogenides via Assisted Nucleation.

The transition-metal chalcogenides include some of the most important and ubiquitous families of 2D materials. They host an exceptional variety of electronic and collective states, which can in principle be readily tuned by combining different compounds in van der Waals heterostructures. Achieving this, however, presents a significant materials challenge. The highest quality heterostructures are usually fabricated by stacking layers exfoliated from bulk crystals, which - while producing excellent prototype devices - is time consuming, cannot be easily scaled, and can lead to significant complications for materials stability and contamination. Growth via the ultra-high vacuum deposition technique of molecular-beam epitaxy (MBE) should be a premier route for 2D heterostructure fabrication, but efforts to achieve this are complicated by non-uniform layer coverage, unfavorable growth morphologies, and the presence of significant rotational disorder of the grown epilayer. This work demonstrates a dramatic enhancement in the quality of MBE grown 2D materials by exploiting simultaneous deposition of a sacrificial species from an electron-beam evaporator during the growth. This approach dramatically enhances the nucleation of the desired epi-layer, in turn enabling the synthesis of large-area, uniform monolayers with enhanced quasiparticle lifetimes, and facilitating the growth of epitaxial van der Waals heterostructures.

Fabrication of 208Pb and 193Ir targets on Al-backing using high/ultra-high vacuum deposition technique for low-energy nuclear reaction experiments

Aiming to study the interplay of different nuclear reactions at low incident energies, thin targets of enriched stable isotopes, 208Pb and 193Ir, have been fabricated at the target development laboratory of the Inter-University Accelerator Centre (IUAC), New Delhi. As a means of preparing a large number of thin isotopically pure targets, physical vapour deposition techniques, (a) resistive heating, for fabrication of 208Pb targets of mass thickness 160-340μg/cm2, and (b) electron-gun evaporation technique, for fabrication of 193Ir targets of mass thickness 17-60μg/cm2, have been employed. The fabricated targets were characterized using Rutherford Backscattering Spectrometry (RBS) and Field Emission Scanning Electron Microscopy (FE–SEM). The thickness of targets was estimated based on the evaporation rate and measured by RBS. The RBS was employed to analyse the samples for trace- and heavy impurities, provided the measurements and analysis suggest that the targets prepared in the present work do not contain any impurities. FE-SEM was employed to examine the surface morphology and microstructure in high resolution. This technique enables the detection of any morphological changes induced by the irradiation process, offering insights into the effects of irradiation on the target films. The targets have been successfully deployed to measure complete and incomplete fusion excitation functions, mass distribution of fission fragments, and forward ranges of target-like recoils in 12C + 208Pb, 193Ir reactions from sub- to above barrier energies. Preliminary data analysis suggests the achievement of high-quality 208Pb and 193Ir target foils.

Biocompatibility assessment of organic semiconductor pigments epindolidione and quinacridone

Organic colorants epindolidione (EPI) and quinacridone (QUI) are commercially available hydrogen-bonded semiconductor pigments. Despite their suitable properties for bioelectronic applications, their biocompatibility has not been thoroughly examined yet. In this study, thin EPI and QUI layers were applied on well plates by vacuum deposition technique followed by short and long-term in vitro biocompatibility study. In vitro testing represents a relatively fast and cheap approach, especially suitable for screening testing and prioritization of materials for further research. LIVE/DEAD assay, cell cycle analysis, adhesion and morphology of NIH 3T3 mouse fibroblasts have been investigated up to 7 days using flow cytometry and fluorescent optical microscopy. In summary, no significant differences were observed in viability, cell morphology, or attachment capabilities between control cells and cells grown on the EPI or QUI surfaces or cells cultivated in medium harvested from EPI- or QUI-coated wells. Our results suggest that both pigments are highly biocompatible. The absence of adverse biological effects of EPI and QUI together with their low cost and availability indicate their high application potential in next-generation bioelectronic devices.

Catalyzing hydrogen production: Exploring plasmonic effects in self-assembled CuO/Cu2O thin films via pulsed laser deposition

Plasmonic catalysis triggers the dissociation of H2 or adsorbed O2 (sluggish processes) under continuous wave excitation via plasmon decay. This is coupled to interband or intraband excitation of d-band or sp-band, respectively, to levels above fermi level of metals. Here, we have studied the plasmonic and photocatalytic behavior in an environment friendly medium with AM 1.5 G sunlight of CuO/Cu2O thin films fabricated by pulsed laser deposition technique in vacuum with varying thickness. We have achieved ∼0.59 kmol h−1g−1H2 production in the CuO/Cu2O film with a thickness of ∼27 nm. The role of plasmons with metal–dielectric and semiconductor–semiconductor interfaces is conducted through both experimental and theoretical approaches. The results suggest that the impact of plasmonic catalysis/synthesis is subject to the dimension, composition, and band alignment of two interface materials.

Bi doped LaOCl and LaOF thin films grown by pulsed laser deposition

Thin films of Bi3+ doped LaOCl and LaOF phosphors prepared via the pulsed laser deposition (PLD) technique in vacuum and different argon (Ar) pressures were compared in order to assess their luminescence properties. All peaks of the X-ray diffraction patterns of the films were consistent with the tetragonal structure of the LaOCl and LaOF, but in the case of LaOF the signal was weaker and not all peaks were present, suggesting some preferred orientation. Photoluminescence measurements revealed that the films exhibited emission around 344 nm for LaOCl:Bi and 518 nm for LaOF:Bi under excitations of 266 nm and 263 nm, respectively. The luminescence from the LaOF:Bi sample was less intense compared to the LaOCl:Bi sample prepared under the same conditions, which was also the case for the powder samples. The amount of ablated material present on the substrate was much less for LaOF:Bi compared to LaOCl:Bi, which is attributed to the greater bandgap and hence weaker absorption of the laser pulses for LaOF:Bi. Therefore phosphors based on LaOCl as the host material were found to be preferable over LaOF under the PLD conditions used in this study.

Analogous Design of a Microlayered Silicon Oxide-Based Electrode to the General Electrode Structure for Thin-Film Lithium-Ion Batteries.

Development of miniaturized thin-film lithium-ion batteries (TF-LIBs) using vacuum deposition techniques is crucial for low-scale applications, but addressing low energy density remains a challenge. In this work, structures analogous to SiOx-based thin-film electrodes are designed with close resemblance to traditional LIB slurry formulations including active material, conductive agent, and binder. The thin-film is produced using mid-frequency sputtering with a single hybrid target consisting of SiOx nanoparticles, carbon nanotubes, and polytetrafluoroethylene. The thin-film SiOx/PPFC (plasma-polymerized fluorocarbon) involves a combination of SiOx and conductive carbon within the PPFC matrix. This results in enhanced electronic conductivity and superior elasticity and hardness in comparison to a conventional pure SiOx-based thin-film. The electrochemical performance of the half-cell consisting of thin-film SiOx/PPFC demonstrates remarkable cycling stability, with a capacity retention of 74.8% up to the 1000th cycle at 0.5 C. In addition, a full cell using the LiNi0.6Co0.2Mn0.2O2 thin-film as the cathode material exhibits an exceptional initial capacity of ≈120 mAh g-1 at 0.1 C and cycle performance, marked by a capacity retention of 90.8% from the first cycle to the 500th cycle at a 1 C rate. This work will be a stepping stone for the AM/CB/B composite electrodes in TF-LIBs.

Metal-insulator-semiconductor photoelectrodes for enhanced photoelectrochemical water splitting.

Photoelectrochemical (PEC) water splitting provides a scalable and integrated platform to harness renewable solar energy for green hydrogen production. The practical implementation of PEC systems hinges on addressing three critical challenges: enhancing energy conversion efficiency, ensuring long-term stability, and achieving economic viability. Metal-insulator-semiconductor (MIS) heterojunction photoelectrodes have gained significant attention over the last decade for their ability to efficiently segregate photogenerated carriers and mitigate corrosion-induced semiconductor degradation. This review discusses the structural composition and interfacial intricacies of MIS photoelectrodes tailored for PEC water splitting. The application of MIS heterostructures across various semiconductor light-absorbing layers, including traditional photovoltaic-grade semiconductors, metal oxides, and emerging materials, is presented first. Subsequently, this review elucidates the reaction mechanisms and respective merits of vacuum and non-vacuum deposition techniques in the fabrication of the insulator layers. In the context of the metal layers, this review extends beyond the conventional scope, not only by introducing metal-based cocatalysts, but also by exploring the latest advancements in molecular and single-atom catalysts integrated within MIS photoelectrodes. Furthermore, a systematic summary of carrier transfer mechanisms and interface design principles of MIS photoelectrodes is presented, which are pivotal for optimizing energy band alignment and enhancing solar-to-chemical conversion efficiency within the PEC system. Finally, this review explores innovative derivative configurations of MIS photoelectrodes, including back-illuminated MIS photoelectrodes, inverted MIS photoelectrodes, tandem MIS photoelectrodes, and monolithically integrated wireless MIS photoelectrodes. These novel architectures address the limitations of traditional MIS structures by effectively coupling different functional modules, minimizing optical and ohmic losses, and mitigating recombination losses.

(Invited) Multifunctional Plasma-Enabled Low Dimensional Nanoarchitectures: From Synthesis to Devices

In this presentation, we will give an overview on our last advances in the exploitation of plasma and vacuum deposition methods for the nanoengineering of thin films and supported low-dimensional materials. A key step in the development of such nanoarchitectures is the implementation of a soft-template procedure based on the use of single-crystal small-molecule nanowires grown on processable substrates under mild conditions. We will demonstrate the application of vacuum and plasma-assisted deposition techniques to develop complex nanowires (NWs) and nanotubes (NTs) with a core@multishell morphology where each shell adds functionality or multifunctionality to the system. The steps required for the integration of these nanomaterials as supported or in-device applications will be presented. Two final applications will drive the presentation, namely, the development of multisource energy harvesters (and self-powered sensors) and novel approaches for smart and efficient de-icing by acoustic waves covering the topics of the 3DScavengers and SOUNDofICE EU projects. The universal character of vacuum and plasma methods allows for the deposition of an unprecedented variety of possibilities, including, organic (small-molecules, organic nanocomposites, polymeric layers), inorganic (metal and metal oxides), hybrid (hybrid perovskite) materials acting as conducting, semiconducting, dielectric, photo-absorbent, piezoelectric or plasmonic components in a multilayer or radial configuration. We will share the results accomplished during the last years in the field of energy harvesting (solar cells,[1-4] piezoelectric and triboelectric nanogenerators[5-7]), semi-transparent nanoelectrodes,[8] wetting [9], de-icing and anti-icing.[10-11] References Filippin, A., Sanchez-Valencia, J., Borras, A. et al. (2017) Nanoscale, 9:8133-8141.Barranco, A., Borras, A., Sanchez-Valencia J. R. et al. (2020) Adv. Ener. Mater 10:1901524.Castillo, J., Borras, A., Sanchez-Valencia J.R. et al. (2022) Adv. Mater. 34:2107739.Obrero, J., Borras A., Barranco, A. (2022) Adv. Ener. Mater. 12:2200812.Filippin, A. N., Borras, A. et al. (2019) Nano Energy 58:476-483.García-Casas, X., Borras, A. et al. (2022) Nano Energy 91:106673.García-Casas, X. Borras, A. et al. Patent application Self-powered triboelectric transductor device for drops and liquids. EP23382176.8Castillo-Seoane, J., Borras, A. et al. (2021) Nanoscale 13:13882.Montes, L., Borras, A. et al. (2021) Adv. Mater. Interf. 21:2100767.Lopez-Santos, C., Borras, A. et al. (2019) Langmuir 35:16876.Del Moral, J., Montes, L., Borras, A. et al. (2023) Adv. Funct. Mater. 2023, 2209421

Vacuum Processed Metal Halide Perovskite Light‐Emitting Diodes

AbstractMetal halide perovskite light‐emitting diodes (PeLEDs) are expected to be the next‐generation display technology due to their unique optoelectronic properties. Currently, the external quantum efficiencies of PeLEDs based on solution‐processed fabrication methods already exceed 20%. However, there are still many challenges existing in solution‐based PeLEDs that inhibit their commercialization. Recently, vacuum deposition techniques of perovskites have drawn much attention because of the ability to grow dense and uniform large‐area perovskite films with precisely controlled thickness, which is compatible with state‐of‐the‐art organic LED manufacturing processes. Despite the promising prospects of vacuum‐based PeLEDs, some challenges remain to be addressed to achieve PeLEDs with both high efficiency and high stability that are required for practical applications such as active‐matrix displays. This requires precise control of the film morphology, composition, and interface during the deposition process through fine‐tuning of the substrate temperature, deposition rate, vacuum level, precursor formulation, and post‐treatment conditions. In this review, it focuses on the key requirements for vacuum‐processed PeLEDs, highlights the recent advances in materials and devices of PeLEDs, and emphasize vacuum evaporation methods as well as the corresponding device performance. Possible approaches to improve the efficiency and the long‐term operational stability of vacuum‐processed PeLEDs are discussed.

Thin alumina-coated polyoxometalates on gold-titania half-shell array photoanode for sustainable plasmonic water oxidation

In solar water splitting, the poor chemical and mechanical durability of photoanode materials under oxidative environments has been raised as a crucial issue. Despite promising water oxidation activity, the stable immobilization of polyoxometalates (POMs) onto photoanodes is very challenging. Here we report sustainable photoelectrochemical water oxidation through the deposition of catalytic POMs onto a plasmonic Au/TiO2 photoanode, followed by the atomic layer deposition of a thin Al2O3 layer. Vacuum deposition techniques were used with polystyrene nanospheres as sacrificial templates to fabricate an Au/TiO2 half-shell array as a photoanode with strong plasmonic absorption and excellent stability in aqueous media. The thin Al2O3 layer serves as a protective layer for [Co4(H2O)2(PW9O34)2]10- (Co4POMs) attached to Au/TiO2 half-shells functionalized with cysteamines. The Al2O3 layer increased the photocurrent and delayed current attenuation by preventing the dissociation of Co4POMs from the surface during the water oxidation. A thicker Al2O3 layer exhibited a higher protection effect but reduced the catalytic activity of Co4POMs in the early stage of water oxidation due to the limited exposure of Co4POMs to electrolytes. Furthermore, regardless of the POMs, the Al2O3 layer also passivated the TiO2 surface, improving electron transfer through the POMs/Au half-shell structure. This work suggests that the catalyst/plasmonic photoelectrode with a thin protection layer is a promising alternative to conventional semiconductor-based photoelectrodes for sustainable and efficient water oxidation.

Epoxy Resin-Assisted Cu Catalytic Printing for Flexible Cu Conductors on Smooth and Rough Substrates.

Flexible copper conductors have been extensively utilized in flexible and wearable electronics. They can be fabricated by using a variety of patterning techniques such as vacuum deposition, photolithography, and various printing techniques. However, vacuum deposition and photolithography are costly and result in material wastage. Moreover, traditional printing inks require posttreatment, which can damage flexible substrates, or grafting polymers, which involve complex processes to adhere to flexible substrates. Therefore, this study proposes a facile method of fabricating flexible metal patterns with high electrical conductivities and remarkable bonding forces on a diverse range of flexible substrates. Catalytic ink was prepared by using a mixture of epoxy resin, copper nanopowder, and nanosilica. The ink was applied to a variety of flexible substrates, including a poly(ethylene terephthalate) (PET) film, polyimide film, and filter paper, using screen printing to establish a bridge layer for subsequent electroless deposition (ELD). The catalytic efficiency was significantly improved by treating the cured ink patterns with air plasma. The fabricated flexible metals exhibited excellent adhesion and desirable electrical conductivity. The sheet resistance of the copper layer on the PET substrate decreased to 9.2 mΩ/□ after 150 min of ELD. The resistance of the flexible metal on the PET substrate increased by only 3.125% after 5000 bending cycles. The flexible metals prepared in this study demonstrated good foldability, and the samples with filter paper and PET substrates failed after 40 and 70 folds, respectively. A pressure sensor with a bottom electrode consisting of a copper interdigital electrode on a PET substrate displayed favorable sensing performance.

All-Thermally Evaporated Blue Perovskite Light-Emitting Diodes for Active Matrix Displays.

With the rapid progress of perovskite light-emitting diodes (PeLEDs), the large-scale fabrication of active matrix PeLED displays (AM-PeLEDs) is gaining increasing attention. However, the integration of high-resolution PeLED arrays with thin-film transistor backplanes remains a significant challenge for conventional spin-coating techniques. Here, the demonstration of large-area, blue-emitting AM-PeLEDs are demonstrated using a vacuum deposition technique, which is regarded as the most effective route for organic light-emitting diode displays. By the introduction of an in situ passivation strategy, the defects-related nonradiative recombination is largely suppressed, which leads to an improved photoluminescence quantum yield of vapor-deposited blue-emitting perovskites. The as-prepared blue PeLEDs exhibit a peak external quantum efficiency of 2.47% with pure-blue emission at 475nm, which represents state-of-the-art performance for vapor-deposited pure-blue PeLEDs. Benefiting from the excellent uniformity and compatibility of thermal evaporation, the 6.67-inch blue-emitting AM-PeLED display with a high resolution of 394 pixels per inch is successfully demonstrated. The demonstration of blue-emitting AM-PeLED display represents a crucial step toward full-color perovskite display technology.

Low-temperature conformal vacuum deposition of OLED devices using close-space sublimation

Close-space sublimation (CSS) has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes (OLEDs). CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200 °C. CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media. The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources. The low temperature and conformal nature of CSS, along with its high material utilization and short process time, make it a promising method for fabricating flexible OLED displays.

Mode-Coupling Generation Using ITO Nanodisk Arrays with Au Substrate Enabling Narrow-Band Biosensing.

Plasmonic metal nanostructures have promising applications in biosensing due to their ability to facilitate light-matter interaction. However, the damping of noble metal leads to a wide full width at half maximum (FWHM) spectrum which restricts sensing capabilities. Herein, we present a novel non-full-metal nanostructure sensor, namely indium tin oxide (ITO)-Au nanodisk arrays consisting of periodic arrays of ITO nanodisk arrays and a continuous gold substrate. A narrow-band spectral feature under normal incidence emerges in the visible region, corresponding to the mode-coupling of surface plasmon modes, which are excited by lattice resonance at metal interfaces with magnetic resonance mode. The FWHM of our proposed nanostructure is barely 14 nm, which is one fifth of that of full-metal nanodisk arrays, and effectively improves the sensing performance. Furthermore, the thickness variation of nanodisks hardly affects the sensing performance of this ITO-based nanostructure, ensuring excellent tolerance during preparation. We fabricate the sensor ship using template transfer and vacuum deposition techniques to achieve large-area and low-cost nanostructure preparation. The sensing performance is used to detect immunoglobulin G (IgG) protein molecules, promoting the widespread application of plasmonic nanostructures in label-free biomedical studies and point-of-care diagnostics. The introduction of dielectric materials effectively reduces FWHM, but sacrifices sensitivity. Therefore, utilizing structural configurations or introducing other materials to generate mode-coupling and hybridization is an effective way to provide local field enhancement and effective regulation.

Solution-processed vanadium oxide by low-temperature annealing for silicon solar cells with hole selective contact

Transition metal oxides (TMOs) with high work function (V2O5, MoO3, WO3) are very promising hole selective materials for high-efficiency crystalline silicon solar cells, as they can provide excellent hole transport and electron blocking capabilities simultaneously. However, the TMOs are typically obtained using vacuum deposition techniques (thermal evaporation, atomic layer deposition or sputtering), for which the preparation process is complex and the requirement for the equipments is relatively high. In this work, we prepared vanadium oxide (V2O5-X) films using low-cost solution method as the hole-selective transport layer for silicon heterojunction solar cells. The low temperature post-annealing treatment at 150 °C reduces the surface roughness of film and improves the passivation contact performance with p-Si. Furthermore, annealing in an oxygen-deficient atmosphere (N2/H2 = 95/5) improves the carrier transport due to increased oxygen vacancies and enhances the surface passivation ascribed to the additional role of hydrogen. Combined with the annealing treatments and optimized device processes, the V2O5-X/p-Si heterojunction solar cells have achieved a conversion efficiency of 17.23%, which is the highest reported so far based on solution-processed V2O5-X for crystalline silicon solar cells.