Rear Electrode Research Articles

Boosting Efficiency in Carbon Nanotube-Integrated Perovskite Photovoltaics.

Carbon nanomaterials (graphene, carbon nanotubes, and graphene oxide) have potential applications for optoelectronics, thanks to their superior electronic and optical characteristics. The remarkable stability of carbon-based perovskite solar cells (PSCs) has attracted significant attention. Herein, a fluorine-doped carbon nanotube (F-CNT) is incorporated into the PSCs as a hole-transporting layer (HTL) in between methylammonium lead iodide (MAPbI3) and the rear electrode to develop an effective MAPbI3/HTL interface. The F-CNT bridges both the MAPbI3 film and the Au electrode and promotes photocarrier extraction and transportation between the two layers. The article presents a simulation-driven optimization approach for the development of efficient CNT-based PSCs. Many factors, such as the total defect density of the perovskite, the shallow acceptor density of the F-CNTs film thickness, the perovskite thickness, parasitic resistances, and temperature, have been studied using SCAPS-1D simulations. Utilizing the photovoltaic software SCAPS-1D, we simulated defect states and interfaces to approximate a realistic perovskite device in our analyses. The CNT-based PSC with an architecture of FTO/TiO2/MAPbI3/F-CNTs/Au achieved an outstanding power conversion efficiency (PCE) of 26.91%, with a fill factor (FF) of 84.23%.

20.4% Power conversion efficiency from albedo-collecting organic solar cells under 0.2 albedo.

Highly efficient bifacial organic solar cells (OSCs) have not been reported due to limited thickness of the active layer in conventional configurations, not allowing for efficient harvesting of front sunlight and albedo light. Here, bifacial OSCs are reported with efficiency higher than the monofacial counterparts. The incorporation of pyramid-based asymmetrical optical transmission (AOT) array to a transparent silver electrode suppresses the escaping of front sunlight without sacrificing the harvesting of albedo light. Parasitic absorption induced by the excitation of surface plasmons in an AOT electrode is further reduced by doping organic emitter in electron transport layer and capping high dielectric constant film to silver. The rear electrode achieves a front transmittance of 7% and a rear transmission of 86%. At a conventional albedo of 0.2, the synergistic effect of AOT and minimized optical loss endow the bifacial OSCs with power conversion efficiency of 20.4%. This work paves the way for the utilization of albedo light in OSCs.

PTAA‐infiltrated thin‐walled carbon nanotube electrode with hidden encapsulation for perovskite solar cells

AbstractIn perovskite solar cells (PSCs), expensive gold or silver metal has traditionally been utilized as the rear electrode for highly efficient performance. In this context, carbon nanotube (CNT) electrodes have been considered promising rear electrodes because of their excellent electrical conductivity, mechanical strength, and chemical stability in PSCs. Despite these favorable characteristics, concerns have been raised about the power conversion efficiency (PCE) and stability of PSCs based on CNTs due to the porosity of CNT electrodes. In this study, we employed both poly(triarylamine) (PTAA) infiltration and rear electrode hidden encapsulation approaches to address issues related to the porosity of thin‐walled carbon nanotube (TWCNT) electrodes to achieve high efficiency and stability. The infiltration of low‐molecular‐weight PTAA into the TWCNT electrode reduced electrode porosity while simultaneously improving the interfacial contact of the TWCNT layer with the perovskite layer. Furthermore, a novel encapsulation design was employed to prevent air and water exposure of the TWCNT electrode, which significantly enhanced device stability. PSCs with TWCNT rear electrodes developed on the basis of these strategies have the best PCE of 19.5% and show long‐term stability, retaining 96% and 74% of the initial PCE after 225 h at maximum power point tracking under AM 1.5G illumination and 916 h at 85°C/85% relative humidity, respectively.image

Harnessing SWCNT absorber based efficient CH3NH3PbI3 perovskite solar cells

This paper investigates the effect of incorporating a single-walled carbon nanotubes (SWCNTs) layer into the perovskite solar cell (PSC) structure as an effective technique to boost energy harvesting. The proposed PSC structure utilizes the SWCNTs layer underneath the CH3NH3PbI3 perovskite layer as an absorbing layer forming a novel design of (ITO/SnO2/CH3NH3PbI3/SWCNTs/NiOx/C) half tandem PSC structure. The suggested PSC structure is numerically analyzed using finite element method (FEM). The effects of varying thickness and doping concentration of the added layer and the material of rear electrode are investigated to maximize the power conversion efficiency (PCE) of the suggested PSC. Results of the 3D opto-electrical study and the energy bandgap analysis confirm that utilizing a 680 nm SWCNTs layer with doping concentration of 1.1 × 1020 cm-3 beneath a 150 nm perovskite layer enhances the PCE and short circuit current density (JSC) to 25.6%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$25.6\\%$$\\end{document} and 31.201mA/cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$31.201 mA/{cm}^{2}$$\\end{document}, respectively due to the improving of the PSC absorption by 27.65%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$27.65\\%$$\\end{document}. Higher performance of the proposed PSC has been achieved by using gold (Au) electrode instead of carbon (C) one, causing total enhancement of PCE and JSC of 6.185%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$6.185\\%$$\\end{document} and 9.18mA/cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$9.18\\;mA/cm^{2}$$\\end{document}, respectively over their values for (ITO/SnO2/CH3NH3PbI3/P3HT/NiOx/C) structure reported in previously published literature. The proposed design can be considered as an efficient alternative to the conventional PSC owing to its higher performance and reduced toxicity.

Effect of electron scattering of microchannel plates on the resolution and halo size of UV image intensifier

Abstract Aiming at the problem that the current theoretical model for calculating the resolution of UV(ultraviolet) low-light level image intensifier is not perfect enough to give the optimization conditions directly, the effects of parameters such as the thickness of anti-ion feedback film, MCP(microchannel plate) bevel angle, the depth of the rear electrode and the length-diameter ratio of the channel plate on the photoelectron transport characteristics of UV low-light level image intensifier are analyzed through systematic theoretical research. Experimental results show that optimizing these parameters can significantly improve the performance of the low-light image intensifier. Specifically, when the thickness of the anti-ion feedback film is 4nm, the bevel angle is 8°, the length-diameter ratio is 50, and the back-end electrode is deepened to 10μm, the theoretical image quality of the UV low-light image intensifier reaches a better level. This study has theoretical guidance significance for the development of high-resolution ultraviolet image intensifiers in the field of optoelectronic imaging, and also plays a key role in improving angular resolution in the application of sun blind ultraviolet warning.

Atom layer deposited TiO2 electron transport layer for silicon heterojunction solar cells to achieve high performance

Silicon/compound heterojunction (SCH) solar cells based on p-type and n-type c-Si wafers using atom layer deposition-TiO2 and low work function metal as the electron transport layer and rear electrode are fabricated. Efficiencies of 20.6 % and 21.6 % are achieved on p-type and n-type silicon solar cells, respectively. High Voc exceeding 700 mV have been realized on both kinds of Si wafers. Special attention has been paid to the SCH solar cells based on p-type c-Si wafers in which the TiO2 electron transport layer serves as the emitter. Carrier transport mechanisms and junction characteristics of the SCH solar cells are analyzed based on dark J-V measurement. The formation of a strong inversion layer at the Si surface region is determined, which implies the high Voc potential of the SCH solar cells based on p-type Si. An optical loss analysis is performed along with a possible solution to further improve the Jsc. The feasibility of TiO2 applied as an efficient electron transport layer (emitter) in p-type SCH solar cells with high performance has been showed.

Investigation of structural, electronic, optical, mechanical, and solar cell performance of inorganic novel Ca3AsI3 compound through DFT and SCAPS-1D

This manuscript thoroughly examines the structural, mechanical, electrical, and optical attributes of Ca3AsI3 through first principles-based DFT simulations. The mechanical study confirms its stability and robustness despite its brittleness. The direct bandgap at the Γ-point registers at 1.577 (2.14) eV with PBE (HSE)), providing evidence of its semiconducting nature. Phonon dispersion showed that the compound is dynamically stable. Detailed optical insights were obtained, and the SnS2/Ca3AsI3 heterostructure was explored using SCAPS-1D, optimizing absorber thickness, doping density, and bulk/interface defect density. Adjusting the rear electrode’s work function enhances PV productivity. Under optimal conditions, the Ag/FTO/SnS2/Ca3AsI3/Ni structure yields a VOC of 1.11 V, JSC of 22.06 mA/cm2, FF of 85.06 %, and a PCE of 20.88 %. So, this proposed structure may be used as integrated circuit integration, waveguides, and solar cell in a near future.

Efficiency improvement of CsSnI3 based heterojunction solar cells with P3HT HTL: A numerical simulation approach

Recently, lead free CsSnI3 based solar cells are gaining popularity among researchers due to their outstanding semiconducting characteristics. To improve the efficiency of the recently suggested ITO/ZnMgO/CsSnI3/P3HT/Au solar cell and examine the effects of the five HTL such as (P3HT, PEDOT:PSS, PTAA, MoO3, CFTS) and ZnMgO as ETL via SCAPS-1D on key performance indicators like PCE, FF, JSC and VOC is the main purpose of this works. The effects of thickness variation, carrier density, each layer’s interface defect, bulk defect density, operating temperature, and front and rear electrode placement have been studied. The PCE, VOC, JSC, and FF have shown 7.03 %, 0.32 V, 33.76 mA/cm2, and 62.50 %, respectively with reference structure’s (ITO/ZnMgO/CsSnI3/Au). The highest PCE, VOC, JSC, and FF is improved to 17.04 %, 0.67 V, 35.61 mA/cm2, and 71.39 %, respectively by adding P3HT layer as a HTL with proposed structures (ITO/ZnMgO/CsSnI3/P3HT/Au) then other four HTL (PEDOT:PSS, PTAA, MoO3, CFTS).

Efficient Bifacial Semitransparent Perovskite Solar Cells Using Down‐Conversion 2D Perovskite Nanoplatelets–Poly(Methyl Methacrylate) Composite Film

Semitransparent perovskite solar cells (ST‐PSCs) hold significant appeal for various applications in smart windows, multijunction tandem devices, bifacial and chargeable devices, etc. Unfortunately, to possess high transparency, the perovskite layer in the ST‐PSCs must be kept relatively thin (<400 nm), which in turn causes insufficient light absorption and thus inferior device performance. Herein, a 2D perovskite nanoplatelets (NPLs)/poly(methyl methacrylate) (PMMA) composite thin layer is applied in the ST‐PSCs to solve these problems. Thanks to its dual function of down‐conversion (DC) effect, converting high‐energy UV photons into low‐energy visible photons to enhance the photocurrent, and interfacial passivation, reducing the nonradiative recombination at the interface, the 2D NPLs–PMMA‐based devices with the different average visible transmittance (AVT) values of perovskite film demonstrate significantly improved power‐conversion efficiency (PCE) compared to the pristine devices, and remarkable UV stability, retaining over 77% of initial PCE after aging under continuous UV illumination for 280 h. More importantly, the full bifacial ST‐PSCs using a transparent MoO3/Au/MoO3 rear electrode exhibits a record PCE of 14.26% and 10.65% with a whole device AVT of 19.4% and 26.9%, respectively, which are among the highest performing ST‐PSCs of the kind reported to date.

Simulation and numerical modeling of high performance CH3NH3SnI3 solar cell with cadmium sulfide as electron transport layer by SCAPS-1D

This work includes the numerical modeling (NM) of solar cells consisting of the active layer of CH3NH3SnI3 and electron transport layer of CdS, by employing a software SCAPS-1D. Organic-inorganic lead-based perovskites are superior in terms of power conversion efficiency. However, there are some serious drawbacks associated with them including poor stability, shorter life time and toxicity. Therefore, it is the demand of the hour to explore alternative materials to overcome these shortcomings. In this regard, tin is a competitive alternative to lead because it has similar electronic and chemical properties. Moreover, it is nontoxic, making it environmentally friendly. However, Sn based perovskite devices are reported with inferior power conversion efficacy, to date. In the present work, we have worked on a novel architecture of solar cells containing CH3NH3SnI3 as a light absorber layer and CdS as electron fetching layer. Optimization of the device was performed numerically by varying physical parameters related to the active layer such as thickness, defect density and shallow acceptor concentration. The proposed architecture of solar cells was proved as an efficient system with Jsc of 33.40 mA/cm2, Voc of 0.878 V, FF of 85.25 %, and PCE of 25.02 %. The temperature analysis has revealed that, temperature higher than 300 K increases the reverse saturation current, seriously degrading the structure of the device, hence limiting the power conversion performance of the solar cell. Furthermore, a rear electrode made of the high work function materials like Pt forms an ohmic junction at the HTL/anode interface, enhancing the performance of the device. Results of this study have paved the way for experimentalists to explore opportunities, to rationalize this architecture for real time applications such as inhouse lighting and laptop/smartphone charging.

Utilizing machine learning to enhance performance of thin-film solar cells based on Sb2(S x Se1-x )3: investigating the influence of material properties.

Antimony chalcogenides (Sb2(S x Se1-x )3) have drawn attention as a potential semiconducting substance for heterojunction photovoltaic (PV) devices due to the remarkable optoelectronic properties and wide range of bandgaps spanning from 1.1 to 1.7 eV. In this investigation, SCAPS-1D simulation software is employed to design an earth abundant, non-toxic, and cost-effective antimony sulfide-selenide (Sb2(S,Se)3)-based thin-film solar cell (TFSC), where tungsten disulfide (WS2) and cuprous oxide (Cu2O) are used as an electron transport layer (ETL) and hole transport layer (HTL), respectively. The PV performance parameters such as power conversion efficiency, open-circuit voltage (V oc), short-circuit current (J sc), and fill factor (FF) are assessed through adjustments in material properties including thickness, acceptor concentration, bulk defect density of the absorber, defect state of absorber/ETL and HTL/absorber interfaces, operating temperature, work function of the rear electrode, and cell resistances. This analysis aims to validate their collective impact on the overall efficiency of the designed Ni/Cu2O/Sb2(S,Se)3/WS2/FTO/Al TFSC. The optimized physical parameters for the Sb2(S,Se)3 TFSC lead to impressive PV outputs with an efficiency of 30.18%, V oc of 1.02 V, J sc of 33.65 mA cm-2, and FF of 87.59%. Furthermore, an artificial neural network (ANN) machine learning (ML) algorithm predicts the optimal PCE by considering five semiconductor parameters: absorber layer thickness, bandgap, electron affinity, electron mobility, and hole mobility. This model, which has an approximate correlation coefficient (R 2) of 0.999, is able to predict the data with precision. This numerical analysis provides valuable data for the fabrication of an environmentally friendly, economical, and incredibly non-toxic efficient heterojunction TFSC.

(Poster Award - 1st Place) Emerging Effect of Vertical-Oriented WSe2 Interfacial Layers in the CIGSe Thin Film Solar Cells

Copper indium gallium selenide (CIGSe) thin film solar cells become popular due to their potential as a solution for green energy and space technology recently. These solar cells have a similar electrical performance to traditional silicon solar cells, making them ideal for light, flexible, and high-performance applications. Molybdenum is a popular material for the rear electrode due to its conductivity and low cost. During the selenizing process of the absorber layer, MoSe2 will be formed between Mo and CIGSe layer, which improves adhesion between Mo and CIGSe and facilitates carrier transport from the absorber layer to the rear electrode. Therefore, previous studies show that oxides or nitride-based materials, such as Titanium Nitride and Alumina, are used as the passivation layer at the back contact to address the trade-off of the critical thickness of the MoSe2 layer. That is, designing a nanostructure and creating a contact hole can attract carriers and avoid current blocking. Similarly, Oxide-based material interfacial layers, such as Molybdenum oxide and tungsten oxide, can also play a role in the obstacle of selenium diffusion and modify the band structure. In this work, a few layers of WSe2 interfacial layer were introduced between the CIGSe absorber layer and Mo electrode. First, 20 nm WOx was deposited on Mo by E-beam evaporation. Second, WOx was selenized by a vertical furnace with ICP coils plasma system to form WSe2. By tuning the substrate temperature of plasma-enhanced selenization process, the full vertically lamellar-oriented WSe2 was formed on Mo. The results show that inserting a few layers of WSe2 improved the efficiency of the CIGS solar cell from 12.5 to 14.3%, with a significant increase in short circuit current density up to 38mA/cm2. This improvement was attributed to the improved carrier transportation through the backside interface, facilitated by the specific vertically lamellar-orientated WSe2 and the induced Gallium gradient measured by TEM, SIMS, and XPS. The remarkable enhancement by WSe2 provides the potential for further applications. Figure 1

Boosting efficiency above 30 % of novel inorganic Ba3SbI3 perovskite solar cells with potential ZnS electron transport layer (ETL)

The inorganic Ba3SbI3 perovskite has emerged as a promising, stable absorber material for efficient and cost-effective solar cells, owing to its intriguing compositional, structural, electrical, and optical properties. This study delves into the potential of Iodide-based Ba3SbI3 perovskites, known for their relative stability, as absorbers in conjunction with a ZnS electron transport layer (ETL) to create a high-performance solar cell heterostructure. Using the SCAPS-1D simulator, we first estimate the absorption spectrum and bandgap of the Ba3SbI3 absorber layer through density functional theory (DFT). This obtained spectrum serves as a crucial input for device simulation. We further optimize the work function of the rear electrode to enhance the photovoltaic (PV) performance of the ZnS/Ba3SbI3 heterostructure solar cell. Various parameters including doping density, absorber thickness, and bulk/interface defect density are carefully considered. Additionally, we investigated generation and recombination rates, current density-voltage (J-V) characteristics, and corresponding quantum efficiency (QE). Under optimized conditions, our study achieves a remarkable maximum power conversion efficiency (PCE) of 30.49 %, accompanied by a photocurrent density (JSC) of 54.63 mA/cm2, fill factor (FF) of 83.75 %, and open circuit voltage (VOC) of 0.67 V in the ITO/ZnS/Ba3SbI3/Ni structure. This comprehensive analysis offers valuable insights and methodologies for the experimental design of high-performance and stable photovoltaic devices based on Ba3SbI3 perovskite.

Liquid Metal‐Based Perovskite Solar Cells: In Situ Formed Gallium Oxide Interlayer Improves Stability and Efficiency

AbstractIn this study, eutectic gallium–indium alloy (EGaIn) liquid metal is used as the rear electrode for perovskite solar cells (PSCs), where the interfacial properties of the device, particularly the beneficial roles of the surface oxide of the liquid metal, are explored. The findings demonstrate that the native oxide of the EGaIn electrode significantly affects the stability of photovoltaic performance and impedance characteristics including series and shunt resistances. Based on the results, the following hypothesis is formulated: the oxide interlayer serves two crucial functions of a barrier against metal diffusion and a tunnel for enhancing charge extraction and transfer. The results of elemental mapping and trap density calculation support the former function of the hypothesis that the oxide film can effectively prevent metal penetration into the perovskite layer. Furthermore, measurements involving capacitance−voltage and time‐resolved photoluminescence confirm that the oxide film on the liquid metal eliminates the interfacial Schottky barrier, promoting efficient charge extraction and transfer processes. Finally, the investigation is extended to develop flexible PSCs using the EGaIn electrode, which consistently exhibits stable performance during repeated bending cycles. Notably, the EGaIn rear electrode can be readily removed and collected through a straightforward acid treatment, offering a promising avenue for efficient cell recycling.

Boosting stability of inverted perovskite solar cells with magnetron-sputtered molybdenum rear electrodes

Boosting stability of inverted perovskite solar cells with magnetron-sputtered molybdenum rear electrodes

Evaluating the performance of efficient Cu2NiSnS4 solar cell—A two stage theoretical attempt and comparison to experiments

In this work, copper nickel tin sulfide (Cu2NiSnS4) as an encouraging alternative absorber for thin-film photovoltaic devices is explored. Here, the Cu2NiSnS4 (CNTS) absorber-based heterojunction solar cell is designed through a two-stage theoretical approach using Solar Cell Capacitance Simulator in one-dimension (SCAPS-1D). Initially four different hole transport materials (MoO3, SnS, NiOx, and PEDOT.PSS) are incorporated at the back interface in experimentally configured Au/Cu2NiSnS4/ZnS/ZnO/ITO cell to boost the device outputs. The MoO3 semiconductor is anticipated as a hole transport layer (HTL) in the heterojunction Ni/MoO3/Cu2NiSnS4/ZnS/ZnO/ITO solar configuration. It is revealed that an appropriate band alignment can be formed at MoO3/Cu2NiSnS4 interface with less interfacial defects among other HTLs with CNTS absorber, thus improving the solar cell outputs. Efficiency is increased from 2.71% to 8.79% for the proposed CNTS-based solar cell. Further optimization is accomplished concerning thickness, defect states, and doping density of the various materials utilized in the heterojunction structure. Defect characteristics at the MoO3/Cu2NiSnS4 and Cu2NiSnS4/ZnS interfaces are also evaluated and optimized to boost the conversion efficiency significantly. Moreover, the effects of operating temperature and rear electrode work function on the outputs of the designed solar device are studied. The aforesaid two-stage optimization yields efficiency of 12.46% with VOC of 1.23 V, JSC of 12.66 mA/cm2, and FF of 79.78%. Therefore, these findings will facilitate the scientific communities to further progress an economical and extremely efficient CNTS-based solar device with a promising MoO3 HTL.

Enhanced optoelectronic coupling for perovskite/silicon tandem solar cells.

Monolithic perovskite/silicon tandem solar cells are of great appeal as they promise high power conversion efficiencies (PCEs) at affordable cost. In state-of-the-art tandems, the perovskite top cell is electrically coupled to a silicon heterojunction bottom cell by means of a self-assembled monolayer (SAM), anchored on a transparent conductive oxide (TCO), which enables efficient charge transfer between the subcells1-3. Yet reproducible, high-performance tandem solar cells require energetically homogeneous SAM coverage, which remains challenging, especially on textured silicon bottom cells. Here, we resolve this issue by using ultrathin (5-nm) amorphous indium zinc oxide (IZO) as the interconnecting TCO, exploiting its high surface-potential homogeneity resulting from the absence of crystal grains and higher density of SAM anchoring sites when compared with commonly used crystalline TCOs. Combined with optical enhancements through equally thin IZO rear electrodes and improved front contact stacks, an independently certified PCE of 32.5% was obtained, which ranks among the highest for perovskite/silicon tandems. Our ultrathin transparent contact approach reduces indium consumption by approximately 80%, which is of importance to sustainable photovoltaics manufacturing4.

Design and simulation of a highly efficient CuBi2O4 thin-film solar cell with hole transport layer

The advancement of thin-film photovoltaic technologies is increasing extensively in today’s world owing to their outstanding optical properties, simple fabrication process, and low-cost. In this work, a solar cell capacitance simulator in one-dimension (SCAPS-1D) has been used to evaluate the output parameters of the heterojunction CuBi2O4-based solar cells with various hole transport layers (HTLs). It is revealed that a p-type cuprous oxide (Cu2O) semiconductor as an HTL ensures proper band alignment at Cu2O/CuBi2O4 interface. The recombination due to minority electrons at the rear side of the CuBi2O4 solar structure with Cu2O HTL can be diminished notably than the device with other HTLs, thus improving the overall outputs of the suggested Cu2O/CuBi2O4/CdS/FTO heterostructure. To realize the behaviors of the proposed PV cell, the thickness and carrier concentration of various films, bulk defects, interface defects, cell resistances, and rear electrode work function of the anticipated CuBi2O4 thin-film photovoltaic device have been optimized. The recombination rates at the interfaces in the proposed heterostructure are also calculated. Moreover, to outline the effects of device input parameters of various materials on vital PV output parameters, adaptable machine learning algorithms have been used to train, test, and calculate the output datasets. High accuracy and low error metrics are confirmed for both the train and test datasets. With 1.0 μm absorber thickness, the efficiency of 29.2% with open-circuit voltage (Voc) of 1.02 V, short-circuit current density (Jsc) of 32.49 mA/cm2, and fill factor (FF) of 87.91% is found for the anticipated solar cell. This investigation suggests that the Cu2O can be effectively employed to scheme a highly efficient, stable, and economical CuBi2O4 solar device.

Enhancing poly-Si contact through a highly conductive and ultra-thin TiN layer for high-efficiency passivating contact silicon solar cells

High-performance passivating contacts with excellent electron selective property is a prerequisite for silicon solar cells with high power conversion efficiency. In this work, a highly conductive, ultra-thin electron-selective titanium nitride (TiN) film is prepared by reactive magnetron sputtering for tunnel oxide passivated contact (TOPCon) solar cells. The deposition parameters, crystal structure, and chemical state were systematically investigated. A higher TiN content and stronger TiN (111) diffraction peak resulted in higher conductivity. We demonstrated that the TiN film possessed a conductivity as high as 5000 S/cm and a relatively low work function of 4.26 eV. An ultra-thin TiN film (1–2 nm) was inserted between the n+ poly-Si and rear electrode to reduce the interface contact resistance and interface barrier height and subsequently obtain better electron transport. The cross-sectional morphology and elemental distribution of the n+ poly-Si/TiN/Ag interface were tested using high-resolution transmission electron microscopy. The developed TiN film was a proof of concept, and it demonstrated an impressive cell efficiency of 24.6% (Voc = 707.1 mV, Jsc = 41.62 mA/cm2, FF = 83.7%) on TOPCon solar cells. Our work provides vital insights and a detailed supplement toward the optimization of electron contact for silicon solar cells or perovskite solar cells. The outcomes of the study indicate the potential for use in applications involving high fill factor photovoltaic devices.

Investigation on Thermal Efficiency Enhancement and Sideband Emission Suppression for Magnetron Injection Gun

At low-power operation, an approach with a capture structure is employed to absorb the trapped electrons for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{Ka}$</tex-math> </inline-formula> -band gyro-traveling wave tube (Gyro-TWT). When the power is further increased, the capture structure cannot play a role and the working current fluctuates. In subsequent experiments, the capture structure was found to have severe traces of melting. According to the position characteristics of the capture structure, the main reason for its melting is the phenomenon of sideband emission from the cathode of magnetron injection gun (MIG). In heat transfer systems of the conventional cathode, the rear electrode emits trapped electrons, which are accelerated by an electric field and bombard the capture structure. We adopted the scheme of adjusting the cathode heat transfer system. The enhanced cathode is called the isolated cathode (ISO-cathode). The test experiment proved that sideband emission is suppressed and thermal efficiency is improved. In the experiment, the cathode power decreased from 85 to 42 W when the operating temperature is at 1050 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C. In the end, the absorbed power of the capture structure is less than about 1/10 of the original power by simulation. The life and reliability of MIG are increased by ISO-cathode. The foundation is laid for further improvement on the average power by ISO-cathode.