Deposition Of SnO2 Research Articles

Conformal SnO2 and NiOx charge transport layers for pragmatic air-processed perovskite solar cells

The industrialization of perovskite (PVK) solar cells (PSCs) necessitates simple manufacturing, cheapness, nontoxicity, high efficiency, and stability. We report an air-processed lead halide PSCs with cheap, nontoxic, stable NiOx and SnO2 as the hole and electron transport layers separately, to meet all the above commercial requests. By preparing the NiOx (water-dispersible) and SnO2 (oil-dispersible) quantum dots (QDs) with good conductivity and energy band matched well with that of PVK, we fabricate inverted PSCs (ITO/NiOx/PVK/SnO2/Ag) with efficiency up to 20.1/14.6% for active areas of 0.0707/1 cm2, under 1 sun simulated illumination with enhanced UV light ratio. The UV-light resistant PSCs reported here will impel their application in the high altitude areas with strong UV light. Importantly, the monodisperse size and dominant (110) plane of SnO2 QDs achieved by controlling the solvothermal parameters, realize the conformal deposition and defect prevention of SnO2, respectively, thus improving the PSC efficiency and stability.

Atomic layer deposition of SnO2 enables fast-dynamics in electrochromic vanadium oxide/polyaniline films

Heterostructure materials hold great promise for electrochromism, but the complexity in coupling the optical and electronic properties of multiple materials remains a challenge. Herein, SnO2 film with excellent transparency and electronic properties is deposited on electro-deposited inorganic-organic vanadium oxide-polyaniline composite films by atomic layer deopisiton (ALD). As a result, the heterostructure strategy stimulated the reaction dynamics, significantly reducing the response time (from 30 s to 5 s). In addition, the thickness of the SnO2 films is found to have a crucial influecne on the electrochromic performance of heterostructure electrodes. Our work highlights the potential of semiconductor films in improving the electrochoromic materials.

Sequential Deposition of Diluted Aqueous SnO2 Dispersion for Perovskite Solar Cells

The widespread use of tin dioxide (SnO2) thin films as electron transport layer (ETL) of perovskite solar cells (PSCs) has been facilitated by commercial SnO2 nanocolloid dispersion. Nevertheless, challenges such as nanoparticle agglomeration have emerged, impacting film quality and interface properties critical for PSC performance. Herein, the efficacy of sequential, multistep spin‐coating of repeatedly diluted SnO2 aqueous suspension as a simple and effective approach to enhance ETL properties is explored. Through systematic experiments using dynamic light scattering, cyclic voltammetry, optical spectroscopy, and photoconductivity, it is demonstrated that the sequential deposition significantly improves the flatness and coverage of SnO2, leading to improved electron transport and transfer from a perovskite layer. Such a synergetic effect enables to fabricate lead iodide PSC (FAPbI3, FA: formamidinium) with a power conversion efficiency of 22.99% compared to 20.48% for the conventional 1‐step SnO2 layer. The findings underscore the potential of sequential SnO2 deposition as a promising technique for robust SnO2 films of photoelectric conversion devices.

Post‐Treated Polycrystalline SnO2 in Perovskite Solar Cells for High Efficiency and Quasi‐Steady‐State‐IV Stability

AbstractThe prominent chemical bath deposition (CBD) method leverages tin dioxide (SnO2) as an electron transport layer (ETL) in perovskite solar cells (PSCs), achieving exceptional efficiency. The deposition of SnO2, however, can lead to the formation of oxygen vacancies and surface defects, which subsequently contribute to performance challenges such as hysteresis and instability under light‐soaking conditions. To alleviate these issues, it is crucial to address heterointerface defects and ensure the uniform coverage of SnO2 on fluorine‐doped tin oxide substrates. Herein, the efficacy of tin(IV) chloride (SnCl4) post‐treatment in enhancing the properties of the SnO2‐ETL and the performances of PSCs are presented. The treatment with SnCl4 not only removes undesired agglomerated SnO2 nanoparticles from the surface of CBD SnO2 but also improves its crystallinity through a recrystallization process. This leads to an optimized interface between the SnO2‐ETL and perovskite, effectively minimizing defects while promoting efficient electron transport. The resultant PSCs demonstrate improved performance, achieving an efficiency of 25.56% (certified with 24.92%), while retaining 95.84% of the initial PCE under ambient storage conditions. Additionally, PSCs treated with SnCl4 endure prolonged light‐soaking tests, particularly when subjected to quasi‐steady‐state‐IV measurements. This highlights the potential of SnCl4 treatment as a promising strategy for advancing PSC technology.

Temperature effects on Cadmium Selenide semiconductor-sensitized solar cells with SnO2 deposition as electron transport layer

Temperature effects on Cadmium Selenide semiconductor-sensitized solar cells with SnO2 deposition as electron transport layer

Drop–Dry Deposition of SnO2 Using Na2SnO3 and Fabrication of SnO2/NiO Transparent Solar Cells

In this work, SnO2 thin films are deposited by drop–dry deposition (DDD), which is a simple, low-cost chemical technique for thin film deposition. The deposition solution contains Na2SnO3 as the Sn source, and is highly stable without spontaneous reactions in the solution. The solution is dropped on a substrate heated to 60°C on a heater plate. According to Auger electron spectroscopy, the deposit will be stoichiometric SnO2. The film is n-type and transparent in the visible range. The pn heterostructure is fabricated by depositing SnO2 on p-type NiO. The NiO film is also fabricated by DDD. Ni(OH)2 is deposited using a solution containing Ni(NO3)2 and NaOH, and then is converted to NiO by annealing at 400°C. The SnO2/NiO structure is transparent in the visible range and shows clear rectification properties and photovoltaic effects. Thus, a transparent solar cell is successfully fabricated by DDD.

Room–temperature hydrogen sensitive Pt–SnO2 composite nanoceramics: Dormancy and a practicable regeneration method

Dormancy has been suggested to be used for metal oxide gas sensors to specifically refer to their response decrease or disappearance after long periods of inactivity at room temperature. In this paper, 1 wt% Pt–SnO2 composite nanoceramics with especially strong responses to hydrogen–containing atmospheres at room temperature, e.g. a response of 11170 to 1 % H2–20 % O2–N2, were successfully prepared through pressing and sintering. A clear dormancy has been observed for them as their responses decreased seriously with time when they were stored in ambient air at room temperature. Commercial ceramic heating plates (Metal Ceramics Heater, MCH) of 10 mm × 10 mm were attached to bars of 1 wt% Pt–SnO2 composite nanoceramics. Dormant bars after 12 months of storage were completely regenerated through a heat–treatment of 200 °C for 10 min by attached MCH ceramic heating plates. According to X-ray photoelectron spectroscopy analyses, the formation of hydroxyl groups on SnO2 in Pt–SnO2 composite nanoceramics and deposition of impurity gases like H2S were proposed responsible for the dormancy, and their removal through mild heat–treatments result in the regeneration. It is suggested that heaters like commercial MCH ceramic heating plates should be included in future room–temperature gas sensors to provide a practicable regeneration from dormancy when needed.

Liquid-phase controlled synthesis of Sb-derived heterostructures

Antimony (Sb) based compounds such as Sb2O3 and Sb2S3 have shown promises in electronics, catalysis and sensing devices. Their functional performances can be further improved by integration with other materials to from composites or heterostructures, which however, usually require tedious procedures with poor morphology control. Herein, we realized direct hydrothermal synthesis of Sb2O3/SnO2 heterostructures and Sb2S3/SnS2 heterostructures by using liquid-phase exfoliated two-dimensional (2D) Sb nanoflakes as precursors. Compared to directly using SbCl3 salt as the reactant, using the Sb nanoflakes enabled the slow release of Sb3+ ions which benefited the better controlled nucleation and growth of Sb2O3 (or Sb2S3) acting as growth templates for the further deposition of SnO2 (or SnS2). As a demonstration, the as-prepared Sb2S3/SnS2 heterostructures were employed for photocatalytic methylene blue (MB) degradation, which exhibited a faster degradation rate compared to Sb2S3 or SnS2 alone. Our work offers an alternative strategy with elemental 2D materials as precursors for the preparation of heterostructured functional materials.

Electrochemical preparation and characterization of a new configuration SnO2 anode and its application for treating petroleum refinery wastewater

In the present work, the feasibility of removing chemical oxygen demand (COD) from petroleum refiner wastewater (PRW) was examined through an anodic oxidation process using a SnO2-copper substrate anode in a prototype tubular batch electrochemical reactor. The SnO2 anode was prepared by cathodic deposition from a nitrate solution and characterized by techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). Effects of current density, [Sn2+]/[HNO3] molar ratio, and time on the properties of the prepared anode were investigated. The XRD results showed that main peaks corresponded to deposition of tetragonal SnO2. Besides, broad peeks were observed indicating that the deposits have a lower degree of crystallinity. The results confirmed that increasing current density higher than 10 mA/cm2 results in formation of a mixture of SnO2 and Sn deposits. Additionally, the results proved that [Sn2+]/[HNO3] molar ratio has the main effect on the electrodeposition process, where keeping this ratio lower than 0.33 is recommended to ensure pure SnO2 film deposition. The best conditions for electrodeposition of SnO2 as a compact film on a copper substrate were a current density of 10 mA/cm2, [Sn2+] of 25 mM, [HNO3] of 125 mM to make a molar ratio of 0.2, and 30 min to confirm the formation of deposits without cracks and having an atomic percent (Sn/O) of 20.6/65. The application of the prepared anode for removing of COD from PRW confirmed a good performance with a removal efficiency of 79 % at current density of 12 mA/cm2, pH of 7.8, and operating time of 150 min in which an energy consumption of 9.93 kWh/kg COD was required. The degradation of COD using the SnO2 electrode was found to obey a pseudo first-order kinetic. The application of anodic oxidation using the new configuration of the SnO2 anode can be considered an eco-friendly process for treating wastewater, featuring easy scale-up to an industrial scale at high removal efficiency and lower cost.

Interface defect formation for atomic layer deposition of SnO2 on metal halide perovskites

With the rapidly advancing perovskite solar cell (PSC) technology, dedicated interface engineering is critical for improving device stability. Atomic layer deposition (ALD) grown metal oxide films have drawn immense attention for the fabrication of stable PSC. Despite the advantages of ALD, the deposition of metal oxides directly on bare perovskite has so far not been achieved without damaging the perovskite layer underneath. In addition, the changes to the physicochemical and electronic properties at the perovskite interface upon exposure to the ALD precursors can alter the material and hence device functionality. Herein, we report on a synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES) investigation of the interface between metal halide perovskite (MHP) absorber and ALD-SnO2 electron transport layer. We find clear evidence for the formation of new chemical species (nitrogen compound, lead dihalides) and an upward band bending in the MHP and downward band bending in the SnO2 towards the MHP/ALD-SnO2 interface. The upward bending at the interface forms an electron barrier layer of ∼400 meV, which is detrimental to the PSC performance. In addition, we assess the effectiveness of introducing a thin interlayer of the organic electron transport material Phenyl-C61-butyric acid methyl ester (PCBM) between MHP and ALD-SnO2 to mitigate the effects of ALD deposition.

Atomically Precise Design of PtSn Catalyst for the Understanding of the Role of Sn in Propane Dehydrogenation.

Propane dehydrogenation (PDH), an atom-economic reaction to produce high-value-added propylene and hydrogen with high efficiency, has recently attracted extensive attention. The severe deactivation of Pt-based catalysts through sintering and coking remains a major challenge in this high-temperature reaction. The introduction of Sn as a promoter has been widely applied to improve the stability and selectivity of the catalysts. However, the selectivity and stability of PtSn catalysts have been found to vary considerably with synthesis methods, and the role of Sn is still far from fully understanding. To gain in-depth insights into this issue, we synthesized a series of PtSn/SiO2 and SnPt/SiO2 catalysts by varying the deposition sequence and Pt:Sn ratios using atomic layer deposition with precise control. We found that PtSn/SiO2 catalysts fabricated by the deposition of SnO x first and then Pt, exhibited much better propylene selectivity and stability than the SnPt/SiO2 catalysts synthesized the other way around. We demonstrate that the presence of Sn species at the Pt-SiO2 interface is of essential importance for not only the stabilization of PtSn clusters against sintering under reaction conditions but also the promotion of charge transfers to Pt for high selectivity. Besides the above, the precise regulation of the Sn content is also pivotal for high performance, and the excess amount of Sn might generate additional acidic sites, which could decrease the propylene selectivity and lead to heavy coke formation. These findings provide deep insight into the design of highly selective and stable PDH catalysts.

Passivation of MXene via atomic layer deposition of SnO2 to achieve improved NO2 sensing

MXene is a promising candidate for low power electronic devices, such as gas sensor at room temperature. However, achieving rapid response and complete recovery and simultaneously addressing the issue of baseline drift due to the oxidation of MXene are challenging for MXene sensors. Herein, we demonstrate a general strategy by using atomic layer deposition (ALD) to passivate Ti3C2Tx MXene. The abundant hydroxyl groups on MXene, which could lead to the oxidation of MXene, facilitate efficient deposition of SnO2. Gas sensor tests reveal that the passivated MXene@SnO2 exhibits a response of 35.2% to 20 ppm NO2, which is approximately three times higher than that of pure MXene. Importantly, the response time to NO2 was as fast as 18 s, with full and complete recovery to baseline within 27 s. Our strategy highlights the prospects of utilizing ALD technique for the development of MXene-based gas sensors.

Low Damage Scalable Pulsed Laser Deposition of SnO2 for p–i–n Perovskite Solar Cells

Pulsed laser deposition (PLD) has already been adopted as a low damage deposition technique of transparent conducting oxides on top of sensitive organic charge transport layers in optoelectronic devices. Herein, SnO2 deposition is demonstrated as buffer layer in p–i–n perovskite solar cells (PSCs) via wafer‐scale (4 inch) PLD at room temperature. The PLD SnO2 properties, its interface with perovskite/C60, and device performance are compared to atomic layer deposited (ALD) SnO2, i.e., state‐of‐the‐art buffer layer in perovskite‐based single junction and tandem photovoltaics. The PLD SnO2‐based solar cells exhibit on par efficiencies (17.8%) with that of SnO2 fabricated using ALD. The solvent‐free room temperature processing and wafer‐scale approach of PLD open up possibilities for buffer layer formation with increased deposition rates while mitigating potential thermal or physical damage to the top organic layers. This is a promising outlook for fully physical vapor‐processed halide PSCs and optoelectronic devices requiring low thermal budget.

SYNTHESIS OF ORTHORHOMBIC TIN DIOXIDE NANOWIRES IN TRACK TEMPLATES

In this work, the synthesis of orthorhombic SnO2 nanowires (NWs) was carried out by electrochemical deposition into prepared SiO2/Si-p ion-track template. Track formations in the SiO2/Si structure were created by irradiation on a DC-60 cyclotron with swift heavy Xe ions with an energy of 200 MeV (Ф = 108 cm−2). A 4% aqueous solution of hydrofluoric acid (HF) was used to form nanoporous templates. Electrochemical deposition (ECD) of SnO2 into the track template was carried out at room temperature, the voltage at the electrodes was 1.75 V. During the ECD process, an electrolyte with the following chemical composition was used: 6 g/l SnCl2 (Sigma-Aldrich) – 25 ml H2O – 2 ml HCl (“reagent grade”; 35%; ρ = 1.1740 g/cm3). The surface morphology of the samples, after the ECD process, was studied on a Zeiss Crossbeam 540 two-beam scanning microscope. The phase composition and crystallographic structure of nanoheterostructures (SnO2-NP/SiO2/Si) with nanopores filled with tin dioxide were studied using X-ray diffraction (XRD) on a multifunctional X-ray diffractometer Rigaku SmartLab. Photoluminescence was measured in the optical range of 320–600 nm using a CM2203 spectrofluorimeter (Solar). The electrical characteristics of the synthesized tin dioxide nanowires were studied using a VersaStat 3 potentiostat from Ametek.As a result, a SnO2-NWs/SiO2/Si nanoheterostructure with orthorhombic crystal structure of SnO2 nanowires was obtained. Photoluminescence excited by light with a wavelength of 240 nm has a low intensity, arising mainly due to defects such as oxygen vacancies and interstitial tin or tin with damaged bonds. Measurement of the current-voltage characteristic showed that the SnO2-NP/SiO2/Si nanoheterostructure obtained in this way contains arrays of p-n junctions.

Atomic layer deposition of SnO2 on In2O3 enables ultrasensitive NO2 detection at room temperature and DFT mechanism research

The unique electronic and chemical properties of metal oxide heterostructures are critical to the development of room temperature (RT) sensors. In this work, we report the design of In2O3/SnO2 heterostructures based on atomic layer deposition (ALD), which regulates the energy band structure of the material and promotes the electron transfer, thus enhancing the adsorption of target gases. The sensor based on In2O3/SnO2 demonstrates outstanding sensing performance at RT with an extreme response of 2900 to 10 ppm NO2, which to our knowledge outperforms the reported metal oxide sensors, as well as a detection limit of 61 ppb. Density functional theory (DFT) calculations show that the charge transfer (0.494 e) and interaction energy (2.19 eV) between In2O3/SnO2 and NO2 are significantly enhanced. This work highlights the critical function of heterostructured materials in enhancing the sensing capabilities of semiconductors, providing some hints for the design of ultrasensitive NO2 sensors.

Drop-Dry Deposition of SnO2 Using a Complexing Agent and Fabrication of Heterojunctions with Co3O4.

The drop-dry deposition (DDD) is a simple chemical technique of thin film deposition, which can be applied to metal oxides. The deposition solution is an aqueous solution including a metal salt and an alkali. However, some metal ions react spontaneously with water and precipitate. This work is the first attempt to use complexing agents in DDD to suppress the precipitation. SnO2 thin films are fabricated using DDD with Na2S2O3 as a complexing agent and via annealing in air. The results of the Auger electron spectroscopy measurement show that the O/Sn composition ratio of the annealed films approached two, indicating that the annealed films are SnO2. The photoelectrochemical measurement results show that the annealed films are n-type. Co3O4/SnO2 heterojunction is fabricated using p-type Co3O4 films which are also deposited via DDD. The heterojunction has rectification and photovoltaic properties. Thus, for the first time, a metal oxide thin film was successfully prepared via DDD using a complexing agent, and oxide thin film solar cells are successfully prepared using only DDD.

Reducing damage of sputtering and improving conductivity of transparent electrodes for efficient semi-transparent perovskite solar cells

Sputtered indium tin oxide (ITO) is widely used as an electrode in semi-transparent and tandem perovskite solar cells. However, damage from sputtering to under layers and the limited conductivity of ITO are still the two main obstacles that hinder further performance improvement of the devices. In this work, the effects and mechanism of sputtering damage and poor conductivity of ITO are investigated based on a traditional perovskite solar cell with bathocuproine (BCP) buffer layer. In order to suppress the sputtering damage, tin oxide (SnO2) is deposited on C60 to replace the BCP buffer layer. However, it is found that the deposition of SnO2 on the non-reactive C60 by atomic layer deposition will result in island growth of SnO2 film, which is the key reason for large dark current in solar cells. Fortunately, the phenomenon is inhibited by decorating C60 surface with WO3 thin film. In order to improve the conductivity of the transparent electrode, an ITO/Au/ITO multilayer architecture is designed. The fill factor (FF) and power conversion efficiency (PCE) of the semi-transparent solar cells (ST-PSCs) with the modified buffer layer and electrodes reached 76.4% and 17.62%, respectively, showing an improvement of FF and PCE when compared to the device with BCP buffer layer and ITO electrode. It is revealed that the optimization also increases the short circuit current of the solar cells. These results provide new strategies for damage reduction of sputtering and performance improvement of ST-PSCs.

SnO2-Based NO2 Gas Sensor with Outstanding Sensing Performance at Room Temperature.

The controlled and efficient formation of oxygen vacancies on the surface of metal oxide semiconductors is required for their use in gas sensors. This work addresses the gas-sensing behaviour of tin oxide (SnO2) nanoparticles for nitrogen oxide (NO2), NH3, CO, and H2S detection at various temperatures. Synthesis of SnO2 powder and deposition of SnO2 film is conducted using sol-gel and spin-coating methods, respectively, as these methods are cost-effective and easy to handle. The structural, morphological, and optoelectrical properties of nanocrystalline SnO2 films were studied using XRD, SEM, and UV-visible characterizations. The gas sensitivity of the film was tested by a two-probe resistivity measurement device, showing a better response for the NO2 and outstanding low-concentration detection capacity (down to 0.5 ppm). The anomalous relationship between specific surface area and gas-sensing performance indicates the SnO2 surface's higher oxygen vacancies. The sensor depicts a high sensitivity at 2 ppm for NO2 with response and recovery times of 184 s and 432 s, respectively, at room temperature. The result demonstrates that oxygen vacancies can significantly improve the gas-sensing capability of metal oxide semiconductors.

Area selective atomic layer deposition of SnO2 as an etch resist in fluorine based processes

Here, we propose SnO2 as a reactive ion etching (RIE) mask in fluorine-based etching processes. Tin forms nonvolatile compounds with fluorine at the process temperatures enabling tin to function as an etch mask. We investigate atomic layer deposition (ALD) of SnO2 on silicon thermal oxide, silicon native oxide, H-terminated Si(001), and polystyrene surfaces using tetrakis(dimethylamino) tin(IV) and H2O at 170 °C to understand film nucleation patterns. Pinhole free films of approximately 1 nm thick SnO2 form on silicon thermal oxide and silicon native oxide and resist etching with SF6 under conditions that etch 0.3 μm into silicon. Nucleation delays were observed on H-terminated Si(001) producing continuous films with pinhole defects. Etch proof-of-concept is studied by UV crosslinking polystyrene, dissolving away non-crosslinked polystyrene to expose native oxide, and depositing 20–100 ALD cycles of SnO2. Well-defined grid patterns are transferred 1.2 μm into Si(001) with SF6 RIE when 50 ALD cycles of SnO2 are grown, which is approximately 4 nm thick.

Enabling a rapid SnO2 chemical bath deposition process for perovskite solar cells

Ultrasonication during the chemical bath deposition of SnO2 produces films with better homogeneity for electron-transport layers in perovskite solar cells.