Tin Oxide Buffer Research Articles

Mitigating Delamination in Perovskite/Silicon Tandem Solar Modules

As perovskite/silicon tandem solar cells head toward industrialization, one emerging challenge relates to the mechanical reliability of these organic–inorganic multilayer devices. Herein, the fracture toughness and interfacial strength of monolithic p–i–n perovskite/silicon tandems are assessed in the context of module integration. While the weakest layer in the tandem stack investigated is found to be C60, used here as electron‐transport layer (interfacial tensile strength of 0.64 MPa), more concerningly, the fracture energy of the C60/tin‐oxide interface is found to be only 1.2 J m−2. The low fracture toughness of perovskite/silicon tandems can encourage crack propagation and large‐scale delamination during processes used for their integration into modules such as cell cutting, interconnection, and vacuum lamination. By improving the tin oxide buffer layer properties and reducing sputtering‐induced internal stress (associated with the transparent top electrode deposition onto the tin the oxide buffer layer), the fracture energy is improved to over 160 J m−2. A second strategy to mitigate delamination due to the low fracture toughness of the cells is tailoring encapsulation and cell processing techniques specifically toward the perovskite/silicon tandem technology. In this work, a critical reliability issue, relevant for any perovskite‐based optoelectronic technology requiring device packaging, is addressed.

Enhancing the Scattering Induced by Gold Periodic Arrays Over Optical Waveguides Through Indium Tin Oxide Buffer Layers

Enhancing the Scattering Induced by Gold Periodic Arrays Over Optical Waveguides Through Indium Tin Oxide Buffer Layers

Importance of the Buffer Layer Properties for the Performance of Perovskite/Silicon Tandem Solar Cells

The power conversion efficiency of two-terminal perovskite/silicon tandem solar cells recently surpassed 30%, demonstrating the great potential of this technology. The most common electron-selective contact is a stack of a buckminsterfullerene film, a tin oxide buffer layer, and a transparent conductive oxide. While research is conducted on improving the fullerene/perovskite interface and on removing the buffer layer, less focus is put on tuning the buffer layer properties. In this work, the interplay of the doping densities in the fullerene film and the tin oxide layer as well as the impact of the tin oxide electron affinity on the device performance is investigated using electrical numerical simulations (technology computer-aided design). The simulated power conversion efficiency increases with higher doping densities in the fullerene film and the tin oxide layer, while an increasing conduction band offset between the two materials leads to a decreasing device performance. The results of this work imply that the properties of the buffer layer directly influence the performance of the tandem solar cell. In addition, the importance of measuring various material and interface characteristics in order to derive an improved device understanding is stressed.

Improved analog switching characteristics of Ta2O5-based memristor using indium tin oxide buffer layer for neuromorphic computing

A memristor is defined as a non-volatile memory switching two-terminal resistor, and a memristor with digital switching characteristics is widely studied as a next-generation non-volatile memory because of its simple structure, high integration density, and low power consumption. Recently, analog memristors with gradual resistance switching (RS) characteristics have garnered great attention because of their potential to implement artificial synapses that can emulate the brain functions. Transition metal oxides are thought to be strong candidate materials for the RS. In particular, tantalum oxide (TaO x )-based memristive devices provide stable and durable switching characteristics. TaO x -based memristors utilize analog switching characteristics and have excellent durability and reliability, so they can be applied as artificial synaptic device. In this study, the characteristics of analog RS using Ta2O5-based memristive devices were investigated. The current level of the Pt/Ta2O5/Pt memristors was improved by adjusting the thickness of Ta2O5. In particular, when an indium-tin-oxide (ITO) buffer layer was added to Ta2O5 forming a Pt/ITO/Ta2O5/Pt heterostructured double-layer device, it showed more symmetrical potentiation and depression characteristics under both polarities than a single-layer device without ITO layer. The symmetrical and linear potentiation and depression characteristics are essential for the development of efficient memristor-based neuromorphic systems. Insertion of the ITO buffer layer improves linearity, symmetry, and stability of the analog RS properties of Ta2O5-based memristors to artificial synapses.

Mechanical Reliability of Fullerene/Tin Oxide Interfaces in Monolithic Perovskite/Silicon Tandem Cells

High-efficiency perovskite-based solar cells comprise sophisticated stacks of materials which, however, often feature different thermal expansion coefficients and are only weakly bonded at their interfaces. This may raise concerns over delamination in such devices, jeopardizing their long-term stability and commercial viability. Here, we investigate the root causes of catastrophic top-contact delamination we observed in state-of-the-art p-i-n perovskite/silicon tandem solar cells. By combining macroscopic and microscopic analyses, we identify the interface between the fullerene electron transport layer and the tin oxide buffer layer at the origin of such delamination. Specifically, we find that the perovskite morphology and its roughness play a significant role in the microscopic adhesion of the top layers, as well as the film processing conditions, particularly the deposition temperature and the sputtering power. Our findings mandate the search for new interfacial linking strategies to enable mechanically strong perovskite-based solar cells, as required for commercialization.

Toward Durably Flexible Nickel Oxide Electrochromic Film by Covering an 18 nm Zinc Tin Oxide Buffer Layer

Toward Durably Flexible Nickel Oxide Electrochromic Film by Covering an 18 nm Zinc Tin Oxide Buffer Layer

Manipulating the morphology of CdS/Sb2S3 heterojunction using a Mg-doped tin oxide buffer layer for highly efficient solar cells

Antimony sulfide (Sb2S3) is an appealing semiconductor as light absorber for solar cells due to its high absorption coefficient, appropriate band gap (~1.7 eV) and abundance of constituent elements. However, power conversion efficiency (PCE) of Sb2S3-based solar cells still lags much behind the theoretically predicted due to the imperfect energy level alignment at the charge transporting layer/Sb2S3 interfaces and hence severe charge recombination. Herein, we insert a high-temperature sintered magnesium (Mg)-doped tin oxide (SnO2) layer between cadmium sulfide (CdS) and fluorine doped tin oxide to form a cascaded energy level alignment and thus mitigate interfacial charge recombination. Simultaneously, the inserted Mg-doped SnO2 buffer layer facilitates the growth of the neibouring CdS film with orientation followed by Sb2S3 film with larger grains and fewer pinholes. Consequently, the resultant Sb2S3 solar cells with Mg-doped SnO2 deliver a champion PCE of 6.31%, 22.8% higher than those without a buffer layer. Our work demonstrates that deliberate absorber growth as well as efficient hole blocking upon an appropriate buffer layer is viable in obtaining solution-processed Sb2S3 solar cells with high performance.

Function and Electronic Structure of the SnO2 Buffer Layer between the α-Fe2O3 Water Oxidation Photoelectrode and the Transparent Conducting Oxide Current Collector

The tin oxide buffer layer between the transparent conducting oxide current collector and the hematite photoelectrode causes considerable water oxidation enhancement of that electrode. The water ox...

Improving carrier extraction in a PbSe quantum dot solar cell by introducing a solution-processed antimony-doped SnO2 buffer layer

The antimony-doped tin oxide buffer layer greatly improve the extraction of carriers in a PbSe QD solar cell.

23.6%-efficient monolithic perovskite/silicon tandem solar cells with improved stability

As the record single-junction efficiencies of perovskite solar cells now rival those of copper indium gallium selenide, cadmium telluride and multicrystalline silicon, they are becoming increasingly attractive for use in tandem solar cells due to their wide, tunable bandgap and solution processability. Previously, perovskite/silicon tandems were limited by significant parasitic absorption and poor environmental stability. Here, we improve the efficiency of monolithic, two-terminal, 1-cm2 perovskite/silicon tandems to 23.6% by combining an infrared-tuned silicon heterojunction bottom cell with the recently developed caesium formamidinium lead halide perovskite. This more-stable perovskite tolerates deposition of a tin oxide buffer layer via atomic layer deposition that prevents shunts, has negligible parasitic absorption, and allows for the sputter deposition of a transparent top electrode. Furthermore, the window layer doubles as a diffusion barrier, increasing the thermal and environmental stability to enable perovskite devices that withstand a 1,000-hour damp heat test at 85 ∘C and 85% relative humidity. Perovskite solar cells can complement silicon photovoltaics in multijunction devices. Here, the authors optimize light harvesting in monolithic perovskite-on-silicon devices and fabricate a certified 23.6% efficient, 1 cm2 tandem solar cell with a perovskite device that withstands damp heat tests.

Deposition temperature induced conduction band changes in zinc tin oxide buffer layers for Cu(In,Ga)Se2 solar cells

Thin film Cu(In,Ga)Se2 solar cells with ALD-deposited Zn1–xSnxOy buffer layers are fabricated and the solar cell properties are investigated for varying ALD deposition temperatures in the range from 90°C up to 180°C. It is found that a process window exists between 105°C and 135°C, where high solar cell efficiency can be achieved. At lower ALD deposition temperatures the solar cell performance is mainly limited by low fill factor and at higher temperatures by low open circuit voltage. Numerical simulations and electrical characterization are used to relate the changes in solar cell performance as a function of ALD deposition temperature to changes in the conduction band energy level of the Zn1–xSnxOy buffer layer. The Zn1–xSnxOy films contain small ZnO or ZnO(Sn) crystallites (<10nm), which may lead to quantum confinement effects influencing the optical band gap of the buffer layer. The ALD deposition temperature affects the size of these crystallites and it is concluded that most of the changes in the ZTO band gap occur in the conduction band level.

The effect of a tin oxide buffer layer for the high yield synthesis of carbon nanocoils

In this paper, we show that the efficiency in the growth of carbon nanocoils is significantly improved by introducing a SnO2 buffer layer. Carbon nanocoils were synthesized by chemical vapor deposition using an Fe–Mg–Co or Fe–Mg–Co–Sn catalyst supported on an Al2O3 substrate coated with a 30nm SnO2 buffer layer. The carbon nanocoil growth rate improved by more than 200% compared with the non-coated substrate when using Fe–Mg–Co–Sn or Fe–Mg–Co catalyst layers 600 or 300nm thick, respectively. The byproduct layer was also reduced significantly, which results in more than 50% gain in the consumption of carbon source gas during the synthetic process. The role for an external Sn supply from the buffer layer is discussed based on the experimental results.

Ultraviolet-illuminated fluoropolymer indium–tin-oxide buffer layers for improved power conversion in organic photovoltaics

We demonstrate that the charge carrier extraction in double heterojunction organic photovoltaic(OPV) devices can be enhanced by inserting an UV-illuminated fluoropolymer polytetrafluoroethylene(PTFE) layer between indium–tin-oxide and the thermal evaporated copper–phthalocyanine(CuPc)/buckyball(C 60) organic active layers. In this work, we show that the anode work function influences the photocarrier collection characteristics, where the short-circuit current and open-circuit voltage increase from 1.6 to 4.8 mA/cm 2 and 0.41 to 0.48 V, respectively after the buffer layer insertion associated primary with the barrier decrease in the ITO/CuPc interface. This result shows the potential of UV-illuminated PTFE as a low-cost stable buffer layer for OPV devices.

Synthesis and Application of Electronic Oxides for Solar Energy

AbstractPlasma-enhanced chemical vapor deposition (PECVD) is being developed as a flexible coating technology for a variety of oxides. In this paper we discuss the synthesis of transparent conducting oxides (TCOs), insulating oxides and electrochromic oxides. Tin oxide was synthesized using mixtures of SnCl4 and O2. By proper control of processing conditions the resistivity of this material may be varied from 10-3 &lt; ρ &lt; 105 Ω-cm. Films of varying resistivity were employed as buffer layers in CdS/CdTe solar cells. Preliminary device results have demonstrated that integration of a tin oxide buffer layer was very beneficial for cell performance. In addition, we demonstrate the PECVD synthesis of WO3 from WF6/O2/H2/Ar mixtures. The plasma process space that yielded adherent, transparent tungsten oxide was established. The deposited films were both amorphous and reversibly electrochromic. High temperature annealing above 400°C converted the films into a polycrystalline state.