ITO Layer Research Articles

Magnetron sputtered silicon thin films for solar cell applications

One of the important directions of research in photovoltaics is the development of new thin-film technology, which can replace the currently used, more expensive bulk silicon technology. The article discusses the findings from research focused on optimizing the parameters for the deposition of silicon thin films with P-type electrical conductivity for applications in photovoltaics. The growth rate was determined depending on the change in substrate temperature using reflectometry and the influence of deposition time on optical properties was determined using UV/VIS spectroscopy. Photovoltaic structures were made on substrates with an ITO layer and their electrical parameters were measured. The authors applied the magnetron sputtering method to deposit the layers, selecting it over the commercially used the chemical vapor deposition (CVD) method. This replacement could alleviate the necessity for high temperatures and broaden the potential applications of thin-film solar cells.

Strong Coupling of Resonant Metasurfaces with Epsilon-Near-Zero Guided Modes.

We study, both theoretically and experimentally, strong interaction between a quasi-bound state in the continuum (QBIC) supported by a resonant metasurface with an epsilon-near-zero (ENZ) guided mode excited in an ultrathin ITO layer. We observe and quantify the strong coupling regime of the QBIC-ENZ interaction in the hybrid metasurface manifested through the mode splitting over 200 meV. We also measure experimentally the resonant nonlinear response enhanced near the ENZ frequency and observe the effective nonlinear refractive index up to ∼4 × 10-13 m2/W in the ITO-integrated dielectric nanoresonators, which provides a promising platform for low-power nonlinear photonic devices.

Optically transparent highly conductive contact based on ITO and copper metallization for solar cells

This paper presents the results of obtaining and studying the electrical and optical characteristics of an optically transparent highly conductive Ni/Cu/Ti/ITO contact in order to reduce electrical resistance losses on the front side of the silicon solar cell. The topology of the contact metallization is a square 50 × 50 mm2 with an interdigitated electrode structure. A Ni/Cu/Ti contact metallization formed on ITO layer reduces the surface resistance by more than 60 times. It has been shown that the use of a Ni/Cu/Ti contact with a finger thickness of at least 1.5 μm and a width of 17 μm was formed is a good alternative to traditional contacts for silicon solar cells based on silver paste.

The composited high reflectivity p-type electrodes with patterned ITO for AlGaN-based ultraviolet light emitting diodes

Composited p-type electrodes with high reflectivity have been investigated in AlGaN-based ultraviolet light emitting diodes (UV-LEDs) to improve the light extraction efficiency, which are composed of a patterned ITO layer and an Al reflector. It is verified that the patterned ITO with a thickness of 30 nm can not only well form Ohmic contact with p-GaN capping layer, but also be nearly 90% transparent to ultraviolet light, and thus presenting a reflectivity of 73% at 280 nm when combined with an Al reflector. Further experimental efforts confirm that the performance of the UV-LEDs is dramatically improved with such p-type electrodes. The maximum light output power and wall plug efficiency in the current range of 0–100 mA are severally increased by 49.8% and 54.2% compared to the device with traditional Ni/Au electrodes.

Chemical bath deposition of SnO2 films on PEN/ITO substrates for efficient flexible perovskite solar cells

Flexible perovskite solar cells (f-PSCs) have achieved significant success. However, high-quality tin dioxide (SnO2) electron transport layers (ETLs) fabricated via chemical bath deposition (CBD) have not been achieved on flexible PEN/ITO substrates. This limitation is primarily due to the corrosion of the poor-quality ITO layer by the strongly acidic CBD solution. Here, we analyzed the reasons for the poor corrosion resistance of ITO films on PEN substrate from multiple perspectives, such as element composition, microstructure, and crystallinity. Then, we proposed a modified CBD method for SnO2 films suitable for flexible PEN/ITO substrates. We employed SnCl2·2H2O as the tin source and regulated the pH of the CBD solution by NH3·H2O, which effectively avoided the corrosion of the ITO layer by the CBD solution and achieved high-quality SnO2 films on the ITO layers. Compared to the commercial SnO2 dispersion, the SnO2 films prepared by this method have smaller grains and higher transmittance. As a result, we achieved an unprecedented power conversion efficiency (PCE) of 20.71% for f-PSCs fabricated on PEN/ITO substrates with SnO2 ETLs by CBD method. This breakthrough facilitates the development of high-performance f-PSCs by a low-cost and large-scale chemical bath deposition of high-quality ETLs on flexible substrates.

Surface-Imprinted Polysiloxane with Recognition Ability Based on an ITO Layer for Rapid Detection of Fusarium oxysporum f. sp. cubense by the Naked Eye.

Direct observation by the naked eye of fluorescence-stained microbes adsorbed on surface imprinted polymers (SIPs) is highly challenging and limited by speed, accuracy and the semiquantitative nature of the method. In this study, we tested for the presence of spores of Fusarium oxysporum f. sp. cubense race 4 (Foc4), which cause severe banana Fusarium wilt disease and reduces the area of banana plants. This kind of spore can become dormant in soil, which means that the detection of secreted molecules (molecular imprinting) in soil may be inaccurate; detection methods such as polymerase chain reaction (PCR) and Raman spectroscopy are more accurate but time-consuming and inconvenient. Therefore, a semiquantitative and rapid SIP detection method for Foc4 was proposed. Based on the ITO conductive layer, a reusable and naked-eye-detectable Foc4-PDMS SIP film was prepared with a site density of approximately 9000 mm-2. Adsorption experiments showed that when the Foc4 spore concentration was between 104 to 107 CFU/mL, the number of Foc4 spores adsorbed and the fluorescence intensity were strongly correlated with the concentration and could be fully distinguished by the naked eye after fluorescence staining. Adsorption tests on other microbes showed that the SIP film completely recognized only the Foc series. All the results were highly consistent with the naked-eye observations after fluorescence staining, and the results of the Foc4-infected soil experiment were also close to the ideal situation. Taken together, these results showed that Foc4-PDMS SIPs have the ability to rapidly and semiquantitatively detect the concentration of Foc in soil, which can provide good support for banana cultivation. This method also has potential applications in the detection of other fungal diseases.

Determination of band offsets at the interfaces of NiO, SiO2, Al2O3, and ITO with AlN

The valence and conduction band offsets at the interfaces between NiO/AlN, SiO2/AlN, Al2O3/AlN, and ITO/AlN heterointerfaces were determined via x-ray photoelectron spectroscopy using the standard Kraut technique. These represent systems that potentially would be used for p-n junctions, gate dielectrics, and improved Ohmic contacts to AlN, respectively. The band alignments at NiO/AlN interfaces are nested, type-I heterojunctions with a conduction band offset of −0.38 eV and a valence band offset of −1.89 eV. The SiO2/AlN interfaces are also nested gap, type-I alignment with a conduction band offset of 1.50 eV and a valence band offset of 0.63 eV. The Al2O3/AlN interfaces are type-II (staggered) heterojunctions with a conduction band offset of −0.47 eV and a valence band offset of 0.6 eV. Finally, the ITO/AlN interfaces are type-II (staggered) heterojunctions with conduction band offsets of −2.73 eV and valence band offsets of 0.06 eV. The use of a thin layer of ITO between a metal and the AlN is a potential approach for reducing contact resistance on power electronic devices, while SiO2 is an attractive candidate for surface passivation or gate dielectric formation on AlN. Given the band alignment of the Al2O3, it would only be useful as a passivation layer. Similarly, the use of NiO as a p-type layer to AlN does not have a favorable band alignment for efficient injection of holes into the AlN.

P‐108: High conductivity transparent electrode with In2O3 – ZnO periodic structure and gradient oxygen concentration

Multilayer structures based on the In‐Zn‐O (IZO) system with modulated oxygen doping have been developed as a TCF (transparent conductive film) alternative to ITO or IGZO layers in the LC and OLED displays. The minimum resistivity (3.37 Ohm*cm) and the maximum concentration of free charge carriers correspond to the layers synthesized in an atmosphere of pure argon, while the maximum mobility (39.18 cm2/V*s) corresponds to the layers synthesized in the atmosphere of both argon and oxygen 99.6%/0.4% mixture. Thin‐film periodic structures with gradient modulation of oxygen content in thickness have been fabricated by periodically changing the oxygen concentration in the composition of the working gas during spraying at a substrate temperature of 100 °C. The structures consist of alternating layers with a high concentration of free charge carriers and layers with high mobility. As a result of the single layers' thicknesses optimization the thin‐film periodic structures with a minimum resistivity of 2.89 Ohm*cm have been made. The resistivity is lower than in homogeneous layers of the same composition. The alternation of layers of optimal thickness provides high carrier mobility, it is inherent to layers synthesized in the atmosphere of 99.6/0.4 argon and oxygen mixture at high concentration. The mobility value is close to the value achieved in the layers synthesized in the pure argon atmosphere.This material provides fabrication of high quality, stable and low cost transparent electrodes or TFT layers with performances corresponding to parameters of traditional materials.

Observation of negative capacitance in silicon heterojunction solar cells: role of front contact in carrier depopulation

The origin of the low-frequency inductive loop in the Nyquist plot of the Ag/indium tin oxide (ITO)/p-a-Si:H/intrinsic hydrogenated amorphous silicon (i-a-Si:H)/c-Si/i-a-Si:H/n-a-Si:H/ITO/Al heterojunction (SHJ) solar cells and their effect on the device performance are investigated by adopting impedance spectroscopy under dark and light. The negative capacitance/low-frequency inductive loop originates from the depopulation of injected charge carriers due to a transport barrier at the p-a-Si:H/ITO interface. The p-a-Si:H hole-selective SHJ device with a low-frequency inductive loop also has shown an S-shape and associated performance degradation in the light current density–voltage characteristics due to the opposing field type transport barrier present at the p-a-Si:H/ITO interface, which was overcome after vacuum annealing at ∼200 °C. However, the NiO x -based hole-selective contact Ag/ITO/NiO x /i-a-Si:H/c-Si/i-a-Si:H/n-a-Si:H/ITO/Al SHJ cells have not shown any low-frequency inductive loop or corresponding S-shape and associated performance degradation due to the optimised contact (minimum resistance) between the NiOx and ITO layers.

Performance of nanoparticle-enhanced thin-film solar cell with near-perfect absorption

This study proposes a thin-film solar cell composed of periodic plasmonic titanium nanoparticles (Ti NPs) and indium phosphide (InP) thin films. By adjusting the size and position of plasma Ti NPs and combining with the transparent conductive layer ITO and anti-reflection layer SiO2, the parameters of InP thin film solar cells can be improved. The experimental results show that the average absorption rate reaches 96 % in the wavelength range of 350–850 nm. The absorption rate reached 99.9 % in multiple wavelength ranges. This study has successfully increased the short circuit current to 31.996mA/cm2, power conversion efficiency (PCE) to 29.634 % and open circuit voltage to 1.053 V of InP thin film solar cells.

Technological parameters of thin-film pulsed laser scribing for perovskite photovoltaics

Abstract Over the past decade, the power conversion efficiency of halide perovskite solar cells has shown a rapid increase to 26.1%. The significant efficiency growth and the relative simplification of the technology for obtaining thin-film solar cells due to liquid printing methods determine the high potential for the low-cost perovskite solar cells manufacturing. However, efficient use of cell geometry is comparable to the size of standard crystalline-Si wafers (156:156 mm and more). Therefore, modular geometry similar to amorphous-Si solar cell approaches is used to scale perovskite solar cells. Serial electrical connection of thin-film cells requires precise processing of the conductive layers that form the device p-i-n structure. The subject of research is the development of a full pulsed laser scribing cycle for inverted perovskite solar cells. In this work, we propose a study of a laser-patterning technology In2O3:SnO2 (ITO) conductive layer and a photoactive perovskite layer Cs0,2(CH(NH2)2)0,8PbI3. Process regimes of transparent conducting electrodes based on ITO and halide perovskite layer Cs0,2(CH(NH2)2)0,8PbI3 laser patterning were obtained. The optimal parameters for the multipass mode processing of ITO and perovskite layer were determined. The cell was electrically isolated at a scribe line width of 30 μm.

Bathocuproine, an old dog, new tricks for boosting the performance of perovskite solar cells

Perovskite solar cells (PSCs) have demonstrated extensive prospects for future applications. However, defects remain the crucial factor that impedes their further advancement in performance, and passivation of the interfaces (such as the buried and/or top interfaces) is regarded as one of the most effective approaches. Herein, we aim to address another important interface, namely, the indium tin oxide/electron transport layer (ITO/ETL) interface in n-i-p structured devices. Since electron transport layers are typically fabricated using commercial nanotin dioxide, which often displays insufficient density. To combat this, we employ the most commonly used bathocuproine (BCP) material to treat the ITO/ETL interface. The incorporation of BCP diminishes the direct contact between the perovskite and ITO layers while also passivating the buried interface and adjusting the crystal orientation of perovskites. Furthermore, the substrate layer exhibits improved transparency, consequently elevating the utilization rate of light by perovskite. As a result, the BCP-based PSC exhibits an impressive efficiency greater than 22%, surpassing the control one of 19.91%, and simultaneously demonstrates excellent stability. Notably, the optimization of this interface has universal applicability for the improvement of PSCs performance.

Photonic Crystal Beam Splitter Electrode in Kesterite Tandem Solar Cells: A Numerical Approach

The majority of numerical research on kesterite tandem solar cells has predominantly focused on a two‐terminal (2T) configuration that utilizes an ideal tunnel junction. Herein, the performance of kesterite tandem solar cells by introducing a photonic crystal structure (1DPC) as intermediate layer in both three‐terminal (3T) and four‐terminal (4T) configurations is investigated. The photonic crystal (1DPC) is designed by stacking ITO and SiO2 layers with the terminal layer consisting of NiO. Optical properties of the 1DPC are modeled. This innovative approach offers several advantages. 1) The 1DPC selectively reflects lower wavelengths, effectively enhancing the short‐circuit current density (Jsc) of the top subcell, while the solar irradiance spectrum at higher‐wavelength optimum for the subcell is not affected. 2) The 1DPC serves as an intermediate electrode, needed for the 3T or 4T configuration. 3) Replacing the conventional Mo back contact with a NiO layer significantly boosts the open‐circuit voltage (Voc) of the top subcell. The findings demonstrate that these configurations exhibit higher performance compared to previously reported results. Furthermore, the utilization of 3T and 4T configurations, incorporating the 1DPC as an electrical beam splitter, provides an effective and accurate design compared to the 2T configuration using ideal tunnel junctions.

High-efficiency top-emitting organic light-emitting diodes based on metal/ITO composite electrodes

High-performance top-emitting organic light-emitting diodes (TEOLEDs) integrating the metal/ITO composite anodes were developed. The results revealed that covering the surface of Al anode with ITO layer could effectively improve the charge injection efficiency and balance the hole–electron charge. The effect of the thickness of ITO on the performance of TEOLEDs with Al/ITO anodes was further studied. The TEOLEDs with Al/ITO (5 nm) anode showed optimized performance, with the current efficiency (CE) and external quantum efficiency (EQE) enhanced by 40.0% and 34.5% compared to that of the OELD with pure Al anode, and increased by 93.1% and 33.5% compared to that of bottom-emitting OLEDs. In addition, the full width at half maximum (FWHM) was narrowed to 36 nm due to the micro-cavity effect of the top-emitting structure and the turn-on voltage decreased to as low as 2.3 V owing to the efficient charge injection and well-matched energy level. In addition, TEOLEDs using Ag/ITO as anode exhibited a slow roll-off of CE and EQE and a narrower FWHM of 30 nm, greatly improving the color purity. The strategy is simple and can significantly improve the efficiency of the TEOLEDs, which promotes the applications of OLEDs in the fields of ultra-high-definition displays and micro-displays.

Single-source thermal deposition of (BA)2(MA)3Pb4I13 perovskite for a novel SnO2NRs/comp-TiO2@ irradiated-ITO based 2D/3D perovskite solar cell: Comparative study of irradiated ITO layer and its effect on device performance

Perovskite solar cells have achieved very good efficiency but their stability is still a big issue. To achieve an efficient a stable perovskite solar cell; a new simple single source thermal evaporation approach has been used to deposit 2D/3D (BA)2(MA)3Pb4I13 perovskite active layer, for realization of novel architecture of stable perovskite solar cell. Bi ions irradiated ITO electrode, coated with compact TiO2 and SnO2 nano-rods (NRs) layers, has been used as ETL. A unique approach is adopted to deliberately place SnO2 NRs horizontally on the surface comp-TiO2 coated irradiated ITO. Four, SnO2NRs/comp-TiO2@ irradiated-ITO based 2D/3D perovskite devices, have been fabricated with 1.2 GeV Bi ions irradiated ITO, at four different fluences (1.3 × 1011, 6.5 × 1011, 1.3 × 1012 and 2.6 × 1012 ions/cm2). Nano-hillocks formed by irradiation proved to contribute for the better performance to a certain point. It was found that the choice of using horizontally place SnO2-NRs in ETL contributed for better performance and stability of proposed device. Among four fabricated devices highest efficiency of 13.6 % is obtained for ITO irradiated with 1.3 × 1012 ions/cm2 fluence which is very encouraging for 2D/3D hybrid perovskite based solar cells in addition to improved performance all the devices showed good stability.

Element Diffusion Induced Carrier Transport Enhancement in High-Performance CZTSSe Self-Powered Photodetector.

Cu2ZnSn(S,Se)4 (CZTSSe) has attracted great interest in thin-film solar cells due to its excellent photoelectric performance in past decades, and recently is gradually expanding to the field of photodetectors. Here, the CZTSSe self-powered photodetector is prepared by using traditional photovoltaic device structure. Under zero bias, it exhibits the excellent performance with a maximum responsivity of 0.77 A W-1, a high detectivity of 8.78 × 1012 Jones, and a wide linear dynamic range of 103dB. Very fast response speed with the rise/decay times of 0.576/1.792 µs, and ultra-high switching ratio of 3.54 × 105 are obtained. Comprehensive electrical and microstructure characterizations confirm that element diffusion among ITO, CdS, and CZTSSe layers not only optimizes band alignment of CdS/CZTSSe, but also suppresses the formation of interface defects. Such a suppression of interface defects and spike-like band alignment significantly inhibit carrier nonradiative recombination at interface and promote carrier transport capability. The low trap density in CZTSSe and low back contact barrier of CZTSSe/Mo could be responsible for the very fast response time of photodetector. This work definitely provides guidance for designing a high performance self-powered photodetector with high photoresponse, high switching ratio, fast response speed, and broad linear dynamic range.

Photovoltaic properties of Cu(In,Ga)(Se,Te)2 thin film solar cells with different tellurium amounts and a copper-poor stoichiometry

In this study, the impact of tellurium addition on the microstructure of the copper indium gallium selenide absorber layer with a copper-poor stoichiometry and the photovoltaic properties of SLG/Mo/CIGS/CdS/ZnO/ITO/Ni-Al-Ni solar cells was investigated. Absorber layer, CdS buffer, ZnO and ITO layers, and the Ni-Al-Ni front contact were produced using three-stage co-evaporation, chemical bath deposition, RF magnetron sputtering, and e-beam evaporation techniques, respectively. The thickness and the composition of the absorber layer were controlled in situ. NaF post deposition treatment were applied to the absorber layer. The addition of tellurium improved the crystal quality by increasing the average grain size and decreased the surface roughness. Decreasing surface roughness increased reflection and thus decreased the amount of sunlight absorbed, which in turn reduced current collection. Open-circuit voltage was effected by impurity level and the grain boundry recombination. While moderate tellurium addition reduced grain boundary recombination, excessive tellurium addition created stress, caused crack formation, and increased recombination by reducing crystal quality. The optimum tellurium amount in the copper-poor CIGS structure was found to be 1.1 atomic percent. The control of the microstructure of the absorber and the efficiency improvement of the solar cell were achieved successfully.

Optical loss analysis of Sb2S3 and Sb2Se3 thin film solar cells: A Quantitative Assessment

Optical loss either by light reflection, or light absorption in different layers of a solar cell, can significantly impact short-circuit current density. In this paper, an optical model has been developed to analyze the optical loss in thin film solar cells made of CdS/Sb2S3 or CdS/Sb2Se3 antimony chalcogenide. This model is based on optical loss from absorption in thin layers and reflection at the interfaces of glass/TCO/CdS/(Sb2S3 or Sb2Se3) only by considering the optical properties of layers (refractive index and extinction coefficient). The transmission and reflection rate of Sb2S3 or Sb2Se3 show almost a similar trend. The absorptivity and relative loss in short-circuit current density (Jsc) versus the thickness of Sb2S3 and Sb2Se3 layers was calculated for two different structures: glass/TCO/CdS/Sb2S3 and glass/TCO/CdS/Sb2Se3. The Sb2Se3 solar cell shows a slightly better conversion performance compared to Sb2S3 solar cell due to lower reflection loss. The light reflection was calculated at four interfaces. The transmission rate of light through TCO, ITO, and CdS layers was calculated to obtain an optimal thickness for these layers. TCO showed a higher transmission rate and thus is preferred in antimony solar cell structures. The variations of (Jsc) and loss for Jsc with different thicknesses of ITO (>20%) or TCO (<20%) contact layers, favoring TCO for its lower optical losses and higher Jsc (24 mA cm−2).

Two-terminal tandem solar cell with Sb2S3/Sb2Se3 absorber pair: achieving 14% power conversion efficiency

Embarking on a journey toward high solar efficiency, this study delves into a two-terminal tandem solar cell (TSC) featuring Sb2S3/Sb2Se3 as an absorber layer. The tandem setup consists of different bandgap (Eg) absorbers to selectively target photon energies: the top cell employs a wide bandgap material to efficiently absorb high-energy photons, while the bottom cell utilizes a lower bandgap material to capture refined photons transmitted from the top cell. This strategy mitigates thermalization and transparent energy losses by assigning distinct photon absorption and conversion roles to the top and bottom cells. Realizing peak efficiency in a tandem configuration rests on the apt choice of active materials for the top and bottom cells. In this regard, a comprehensive study is presented, introducing a TSC architecture that pairs an Sb2S3-based top cell (Eg 1.7 eV) with a Sb2Se3-based bottom cell (Eg 1.2 eV). Through meticulous analysis, the performance of these cells in the tandem setup is analyzed, employing methods such as filtered spectrum analysis and current-matching strategies. The Sb2S3/Sb2Se3 tandem design incorporates a critical tunnel recombination junction facilitated by an ITO layer. Noteworthy is the investigation’s uncovering of impressive metrics for the tandem device, encompassing an open-circuit voltage (VOC) of 1.58 V, a current density (JSC) of 15.50 mA.cm−2, and a fill factor (FF) of 56.90%. This collective attainment culminates in an extraordinary power conversion efficiency of 14%. The insights gleaned from this study hold substantial promise for the future development of monolithic TSC. By adroitly harnessing the distinctive strengths of Sb2S3 and Sb2Se3 materials within a tandem configuration, a clear trajectory is charted toward momentous advancement in solar energy conversion technology.

From D-shaped to D-shape optical fiber – A universal solution for sensing and biosensing applications: Drawn D-shape fiber and its sensing applications

We verified experimentally a new method of development of well know D-shape fibers. Instead of mechanical or chemical postprocessing of standard fibers, we have developed a D-shaped preform and further processed it on a fiber drawing tower Inversion of the fabrication process allows to obtain hundreds of meters of uniform sensing fiber with a thermodynamically flattened sensing surface. We have developed fibers with a core of 7 by 8 µm, a 2 µm distance between the core and sensing surface, and its roughness of RMS = 40 nm. As a proof-of-concept, we have developed a lossy-mode resonant sensor with a 320 nm ITO layer and demonstrated its sensitivity of 550 nm/RIE.