Search Results (45)

Silicon nanowires (SiNWs) fabricated by Ag-assisted metal-assisted chemical etching (MACE) exhibit excellent light-trapping performance, yet their fragile high-aspect-ratio morphology severely limits reliable metallization in photovoltaic devices. Conventional electrode deposition methods often fail on dense SiNW arrays due to poor mechanical stability of the nanowire tips, leading to delamination, inhomogeneous coverage, and high contact resistance. In this work, we introduce a maskless laser-based truncation technique that selectively shortens MACE-derived SiNWs to controlled residual heights of 300–500 nm exclusively within the regions intended for electrode formation, while preserving the full nanowire morphology in active areas. A detailed parametric study of laser power, scanning speed, and pulse repetition frequency allowed the identification of an optimal processing window enabling controlled tip melting without damaging the nanowire roots or the crystalline silicon substrate. High-resolution SEM imaging confirms uniform planarization, well-preserved structural integrity, and the absence of subsurface defects in the laser-processed tracks. Optical reflectance measurements further demonstrate that introducing 2% and 5% truncated surface fractions—corresponding to the minimum and maximum metallized front-grid coverage in industrial Si solar cells—results in only a minimal reflectance increase, preserving the advantageous the light-trapping behavior of the SiNW texture. The proposed laser truncation approach provides a clean, scalable, and industrially compatible route toward creating electrode-ready surfaces on nanostructured silicon, enabling reliable metallization while maintaining optical performance. This method offers strong potential for integration into silicon photovoltaics, photodetectors, and nanoscale electronic and sensing devices. Full article

This study proposed a novel perovskite/silicon heterojunction (SHJ) tandem device structure without an interlayer, represented as ITO/NiO/perovskite/SnO₂/MoO_X/i-a-Si:H/n-c-Si/i-a-Si:H/n-a-Si:H/Ag, which was investigated by Silvaco TCAD software. The recombination layer in this structure comprises the carrier transport layers of SnO₂ and MoO_X, where MoO_X serves dual functions, acting as the emitter for the SHJ bottom cell and as part of the recombination layer in the tandem cell. First, the effects of different recombination layers are analyzed, and the SnO₂/MoO_X layer demonstrates the best performance. Then, we systematically investigated the impact of the carrier concentration, interface defect density, thicknesses of the SnO₂/MoO_X layer, different hole transport layers (HTLs) for the top cell, absorption layer thicknesses, and perovskite defect density on device performance. The optimal carrier concentration in the recombination layer should exceed 5 × 10¹⁹ cm⁻³, the interface defect density should be below 1 × 10¹⁶ cm⁻², and the thicknesses of SnO₂/MoO_X should be kept at 20 nm/20 nm. CuSCN has been found to be the optimal HTL for the top cell. When the silicon absorption layer is 200 μm, the perovskite layer thickness is 470 nm, and the defect density of the perovskite layer is 10¹¹ cm⁻³, the planar structure can achieve the best performance of 32.56%. Finally, we studied the effect of surface texturing on the SHJ bottom cell, achieving a power conversion efficiency of 35.31% for the tandem cell. Our simulation results suggest that the simplified perovskite/SHJ tandem solar cell with a dual-functional MoO_X layer has the potential to provide a viable pathway for developing high-efficiency tandem devices. Full article

The integration of perovskite with silicon for constructing tandem solar cells (TSCs) represents a promising route in photovoltaic technology. The hybrid sequential deposition (HSD) method, combining thermal evaporation and spin-coating, is crucial for developing perovskite films in textured perovskite/silicon tandem solar cells. However, the process faces challenges due to incomplete reactions caused by the dense perovskite coverage layer (CPCL) formed from high-crystallinity precursors. The CPCL hinders the diffusion of organic salts into the bottom precursor layer, leading to performance degradation and accelerated device aging. Herein, this study explores several polar solvents as additives to n-butanol (nBA) solvent in order to enhance the permeability of organic salts through the CPCL, and we demonstrate that dimethyl sulfoxide (DMSO) as an additive solvent can effectively assist organic salts in rapidly diffusing through the precursor layer, thereby promoting the complete transformation of uniform perovskite crystals. The resulting perovskite films exhibited complete conversion, uniform crystallization, and improved quality. As a result, the target TSCs achieved an increased maximum power conversion efficiency (PCE) of 29.12%. This study offers a robust pathway for depositing high-quality perovskite films on industrial-grade textured silicon substrates, laying a solid foundation for advancing perovskite/silicon tandem solar cells technology. Full article

This research, which involved a comprehensive methodology, including depositing electroplated copper on a copper seed layer and Al-doped ZnO (AZO) thin films on textured silicon substrates using DC magnetron sputtering with varying substrate heating, has yielded significant findings. The study thoroughly investigated the effects of substrate temperature (Ts) on copper adhesion strength and morphology using the peel force test and electron microscopy. The peel force test was conducted at angles of 90°, 135°, and 180°. The average adhesion strength was about 0.2 N/mm for the samples without substrate heating. For the samples with substrate heating at 100 °C, the average peeling force of the electroplated copper film was about 1 N/mm. The average peeling force increased to 1.5 N/mm as the substrate heating temperature increased to 200 °C. The surface roughness increases as the annealing temperature of the Cu/AZO/Si sample increases. These findings not only provide a reliable and robust method for applying AZO transparent conductive films onto silicon solar cells but also underscore its potential to significantly enhance the efficiency and durability of solar cells significantly, thereby instilling confidence in the field of solar cell technology. Full article

Bifacial photovoltaic (PV) modules can capture both front and rear incident light simultaneously, thereby enhancing their power output. Achieving uniformity in rear incident light is crucial for an efficient and a stable operation. In this study, we present a simple, yet effective textured rear reflector, designed to optimize the performance and stability of bifacial PV modules. The three-dimensional textured surface was created using an ethylene vinyl acetate sheet (EVA) through a hot-press method at 150 °C. Subsequently, the textured EVA surface was coated with solution-processed silver ink, increasing the reflectance of the textured reflector through a low-temperature process. The integration of the developed textured rear reflector into bifacial crystalline silicon (c-Si) PV modules resulted in an additional 6.9% improvement in power conversion efficiency compared to bifacial PV modules without a rear reflector, particularly when the rear reflector is close to the PV module. Furthermore, the textured rear reflector may mitigate current mismatch among cells by randomizing incident light and uniformly redistributing the reflected light to the PV cells. Consequently, the proposed textured reflector contributes to the enhanced performance and stability of bifacial PV modules. Full article

Solar cells play an increasing role in global electricity production, and it is critical to maximize their conversion efficiency to ensure the highest possible production. The number of photons entering the absorbing layer of the solar cell plays an important role in achieving a high conversion efficiency. Metal nanoparticles supporting localized surface plasmon resonances (LSPRs) have for years been suggested for increasing light in-coupling for solar cell applications. However, most studies have focused on materials exhibiting strong LSPRs, which often come with the drawback of considerable light absorption within the solar spectrum, limiting their applications and widespread use. Recently, aluminum (Al) nanoparticles have gained increasing interest due to their tuneable LSPRs in the ultraviolet and visible regions of the spectrum. In this study, we present an ideal configuration for maximizing light in-coupling into a standard textured crystalline silicon (c-Si) solar cell by determining the optimal Al nanoparticle and anti-reflection coating (ARC) parameters. The best-case parameters increase the number of photons absorbed by up to 3.3%. We give a complete description of the dominating light–matter interaction mechanisms leading to the enhancement and reveal that the increase is due to the nanoparticles optically exhibiting both particle- and thin-film characteristics, which has not been demonstrated in earlier works. Full article

This study investigated the use of a pure copper seed layer to improve the adhesion strength and reduce the residual stress of electroplated copper films for heterojunction technology in crystalline solar cells. The experiment involved depositing a copper seed layer and an indium tin oxide (ITO) layer on textured silicon using sputtering. This resulted in the formation of a Cu(s)/ITO/Si structure. Following this step, a 10 µm thick copper layer was electroplated onto the Cu(s)/ITO/Si structure. Various characterization techniques were employed to evaluate the electroplated copper films’ microstructures, residual stress, and adhesion strength. The microstructures of the films were examined using a scanning transmission electron microscope (STEM), revealing a twin structure with a grain size of approximately 1 µm. The residual stresses of the as-deposited and annealed samples were measured using an X-ray diffractometer (XRD), yielding values of 76.4 MPa and 49.1 MPa, respectively. The as-deposited sample exhibited higher tension compared to the annealed sample. To assess the adhesion strength of the electroplated copper films, peel-off tests were conducted at a 90° angle with a constant speed of 30 mm/min. The peel force, measured in units of N/mm, was similar for both the as-deposited and annealed samples. Specifically, the peel force for electroplating copper on the copper seed layer on the ITO was determined to be 2.6 N/mm for the maximum value and 2.25 N/mm for the average value. This study demonstrated that using a pure copper seed layer during electroplating can improve adhesion strength and reduce residual stress in copper films for heterojunction technology in crystalline solar cells. These findings contribute to the development of more reliable and efficient solar-cell-manufacturing processes. Full article

Copper nitride (${\mathrm{Cu}}_3\mathrm{N}$), a metastable poly-crystalline semiconductor material with reasonably high stability at room temperature, is receiving much attention as a very promising next-generation, earth-abundant, thin film solar light absorber. Its non-toxicity, on the other hand, makes it a very attractive eco-friendly (greener from an environmental standpoint) semiconducting material. In the present investigation, ${\mathrm{Cu}}_3\mathrm{N}$ thin films were successfully grown by employing reactive radio-frequency magnetron sputtering at room temperature with an RF-power of 50 W, total working gas pressure of $0.5\mathrm{Pa}$, and partial nitrogen pressures of $0.8$ and $1.0$, respectively, onto glass substrates. We investigated how argon affected the optical properties of the thin films of Cu${}_3$N, with the aim of achieving a low-cost solar light absorber material with the essential characteristics that are needed to replace the more common silicon that is currently in present solar cells. Variable angle spectroscopic ellipsometry measurements were taken at three different angles, ${50}^{\circ }$, ${60}^{\circ }$, and ${70}^{\circ }$, to determine the two ellipsometric parameters psi, $\psi$, and delta, $\Delta$. The bulk planar ${\mathrm{Cu}}_3\mathrm{N}$ layer was characterized by a one-dimensional graded index model together with the combination of a Tauc–Lorentz oscillator, while a Bruggeman effective medium approximation model with a $50\%$ air void was adopted in order to account for the existing surface roughness layer. In addition, the optical properties, such as the energy band gap, refractive index, extinction coefficient, and absorption coefficient, were all accurately found to highlight the true potential of this particular material as a solar light absorber within a photovoltaic device. The direct and indirect band gap energies were precisely computed, and it was found that they fell within the useful energy ranges of $2.14$–$2.25$ eV and $1.45$–$1.71$ eV, respectively. The atomic structure, morphology, and chemical composition of the Cu${}_3$N thin films were analyzed using X-ray diffraction, atomic force microscopy, and energy-dispersive X-ray spectroscopy, respectively. The Cu${}_3$N thin layer thickness, profile texture, and surface topography of the ${\mathrm{Cu}}_3\mathrm{N}$ material were characterized using scanning electron microscopy. Full article

As Si single-junction technology is approaching its Shockley–Queisser theoretical limit, relevant efforts are being expended towards the development of multi-junction modules. In this work, we employ an optical model based on Monte Carlo ray tracing to compare four different multi-junction modules in a voltage-matched two-terminal (VM2T) configuration. In particular, we took into consideration the VM2T coupling of crystalline silicon cells with CuInxGa1-xSe2 (CIGS), CdTe, GaAs and perovskite (PVK) solar cells. We optimized the thicknesses of each layer in the top sub-module and determined the performance of VM2T modules in the Shockley–Queisser theoretical limit. We also considered the possibility of using modules in which the top Si surface is flat to determine the performance drop due to the absence of the texturization on the top Si surface. Moreover, we determined the optimal bandgap energy of PVK in a VM2T PVK/Si module as well as the highest efficiency achievable. Lastly, we show that when using state-of-the-art cells, the highest VM2T efficiency achievable for the considered materials is 34.2% under standard test conditions. Full article

The implementation of a texturing pattern on the surface of a solar cell is well known for reducing reflection, thus increasing the absorption of sunlight by the solar cell. Nanowires (NWs) that are large in their height have been widely used for this purpose. Through rigorous numerical simulations, this work explores the benefits of short but index-matched NWs and how these designs are also affected by surface recombination. Additionally, this work further optimized power conversion efficiency (PCE) by placing two or three NWs of different heights and diameters on top of each other to mimic the performance of two-NW and three-NW ARC designs with PCEs of 16.8% and 17.55%, respectively, when a radial pn junction is considered. These are the highest reported so far for such a thin silicon solar cell. Furthermore, we also show how these designs were impacted by surface recombination velocity and compare these findings to simple NWs of different heights and diameters. Full article

Front surface texturing is a common method used to improve the optical performance of photovoltaic devices. However, traditional texturing techniques may be challenging in some cases, such as when dealing with ultra-thin substrates. Textured polymer films on such devices would be an alternative approach. This paper reports a study of NOA81 thin films with a bionic lotus leaf surface structure on monocrystalline silicon solar cells. Inspired by the surface structure of natural lotus leaves, we successfully prepared a bionic lotus leaf microstructure film on the surface of solar cells based on NOA81 using polydimethylsiloxane (PDMS) polymer and nanoimprinting methods. Scanning electron microscopy (SEM) images showed that the surface structure of the NOA81 thin film was the same as that of natural lotus leaves. A UV-Vis spectrophotometer with an integrating sphere was used to measure the reflectance of the textured NOA81 film on the silicon wafer. Results showed that the textured NOA81 film could effectively reduce the reflectance of the silicon wafer surface. We also used finite-difference time-domain (FDTD) simulation to verify this conclusion further. Finally, the I-V characteristics of the prepared solar cells with the textured NOA81 film were investigated, and the highest photovoltaic efficiency was measured to be about 16.07%, effectively improving the photoelectric conversion efficiency. In addition, the film with textured NOA81 can be used as a protective film for monocrystalline silicon solar cells. Full article

This paper characterizes the surface modification on silicon surfaces with different patterns (circle, pyramid) using a nanosecond fiber laser with different parameters, which enhances its anti-reflection property. The influence of textured and untextured silicon surfaces and their structural properties were evaluated. It has a long absorption path (200–1000 nm) and a rougher surface due to surface modifications, which results in a 40% decrease in incident light reflectance, especially in pyramid-shaped dimples with 70 µm size, helping to trap more light in solar cells where the anti-reflecting surface is a crucial need for devices used in optical and photovoltaic applications to operate more effectively. Scanning electron microscope (SEM) and atomic force microscopy (AFM) are used to examine the surface features to determine the process’s effectiveness and recognize the development of patterns that are deep enough to trap light. XRD and micro-Raman spectroscopy were used to examine the irradiated surface’s crystallographic structure and crystallinity change. Full article

In the current study, we aim to limit the power dissipation in amorphous silicon solar cells by enhancing the cell absorbance at different incident angles. The current improvement is justified by adding the single-period of ternary 1D photonic crystal with texturing on the top surface, which acts as an anti-reflecting coating. The texturing shape gives the photons at least two chances to localize inside the active area of the cell. Therefore, it increases the absorbance of the cell. Moreover, we add binary one-dimensional photonic crystals with the features of a photonic band gap, which acts as a back mirror to return the photons that were transmitted inside the cell’s active region. The considered structure is demonstrated by the well-defined finite element method (FEM) by using COMSOL multiphysics. Full article

Silicon, as the most abundant element in the earth’s crust and the most common material used in electronic and optical equipment, has attracted the attention of many individuals to change the properties of this material, improving its electronic and optical properties. One of these efforts relies on the reduction of surface reflection by making use of different methods. However, among them, the use of lasers in creating surface microstructures has been of special importance because there is no need for masks and other additional materials. In this work, a theoretical method is utilized to analyze these textures with the theorem of diffraction grating on a micrometer scale. The surface reflection of the microstructure created by excimer laser exposure on a silicon surface is simulated. The theoretical Coordinate transformation method (C method) gives out notable results against the experimental records by approximating triangular and trapezoidal microstructures. The model is useful for predicting the reflective response of the modified microstructural morphology. One of the main applications is the texturing of the solar cell front faces to enhance their efficiency, mainly due to photon trapping. Full article

This paper reports on a facile bottom-up method for the direct integration of a silicon (Si)-magnesium silicide (Mg₂Si) heterojunction solar cell (HSC) with a textured rear reflector made of stainless steel (SS). Modified wet chemical etching and post processing of SS substrates resulted in the formation of both a rough surface texture and diffusion barrier layer, consisting of magnetite (Fe₃O₄) with reduced optical reflection. Then, Si, Mg₂Si and CaSi₂ layers were stepwise thermally evaporated onto the textured SS surface. No traces of Fe and Cr silicide phases were detected by Raman spectroscopy, confirming effective suppression of impurity diffusion from the SS to the upper layers at least at temperatures required for Si deposition, as well as Mg₂Si and CaSi₂ formation. The obtained black-SS/Fe₃O₄/Si/Mg₂Si/CaSi₂ sample preserved, to some extent, its underlying textured morphology and demonstrated an averaged reflection of 15% over the spectral range of 200–1800 nm, while its prototype HSC possessed a wideband photoresponse with a photoelectric conversion efficiency of 7.5% under AM1.5 illumination. Moreover, Si layers deposited alone onto a black-SS substrate demonstrated competitive antireflection properties compared with black Si (b-Si) obtained by traditional top-down etching approaches, and hybrid b-Si/textured-SS structures with a glue-bonded interlayer. Full article