Single Crystal Silicon Solar Cells Research Articles

Mechanically programmable substrate enable highly stretchable solar cell arrays for self-powered electronic skin

Development of stretchable solar cells to accommodate large strain without sacrificing the power conversion efficiency is challenging. This study presents a novel approach to manufacture highly stretchable solar cell arrays, which can be integrated into wearable medical devices to operate under challenging environments. Overcoming the limitations of rigid metal wires, liquid metal wires are employed to connect single crystal silicon solar cells, ensuring both high conversion efficiency and exceptional stretchability (up to 100%). The manufacturing process introduces embedding electrospinning films into elastic silicone substrates to create a tight bond between rigid solar cells and stretchable substrates with programmable strain capabilities. Notably, a stretchable interconnect wire is efficiently fabricated using the semi-liquid metal template printing technique and demonstrates remarkable conductivity (up to 6 × 106 S/m). Individual structural unit of solar cell presents an impressive tensile rate of 200%, and endures up to 5000 cycles of tensile testing. The overall solar cell array exhibits outstanding adaptability to extensive bending and twisting, with a mere 0.1% short-circuit current reduction in its maximum stretched state. The stretchable photovoltaic device is successfully employed in creating self-powered electronic skin for continuous real-time monitoring of parameters, showcasing its valuable potential in wearable medical electronic devices and comprehensive sports health monitoring.

Effect of nickel doping on the spectral sensitivity of silicon solar cells

In the modern industrial production of solar cells (SC), there is a growing trend to utilize “solar silicon” as the base material due to its cost-effectiveness. However, solar silicon possesses a drawback - it has a shorter lifetime of minority charge carriers (MCC), making it challenging to achieve high efficiency in solar cells. To address this limitation and improve the efficiency of solar cells based on “solar silicon,” two key objectives need to be met. Firstly, it is essential to increase the lifetime of photogenerated charge carriers. Secondly, there is a need to minimize both optical and electrical energy losses. To achieve an increase in the lifetime of minority charge carriers in SCs, a process called gettering can be employed. This process involves utilizing clusters of nickel atoms to trap uncontrolled impurity atoms. The paper presents the results of a study on the additional doping of silicon solar cells with nickel atoms, for factors affecting the long-wave and short-wave efficiency. Nickel doping has been shown to increase the efficiency of solar cells. It is determined that in the visible region of the spectrum the spectral sensitivity of a silicon solar cell doped with nickel is higher up to 25÷35% due to a decrease in surface recombination. Technological recommendations for nickel doping of single-crystal silicon solar cells are proposed to be combined without significant changes with the standard technological process for manufacturing solar cells.

Down-shifting and antireflective effects of ZnO/PMMA thin films and their influence on silicon solar cells performance

The down-shifting effect of nanostructured II-VI semiconductors like zinc oxide (ZnO) is an attractive feature that can be exploited for the performance enhancement of silicon solar cells. The UV-region of the solar spectrum can be harvested more efficiently by the silicon solar cell after being absorbed by ZnO quantum dots (QDs) and re-emitted in the visible range (centered ⁓510 nm). Additionally, the polymeric matrix (PMMA) used for the fabrication of the ZnO/PMMA thin films can serve as an antireflective layer, enabling a better overall solar radiation absorption. The present study discusses the synthesis and characterization of photoluminescent ZnO QDs and their effect on the performance of in-house-fabricated single crystal silicon solar cells. The down-shifting effect of the colloidal quantum dots was characterized by collecting and analyzing their absorption and photoluminescence spectra. The structural characterization of the obtained ZnO QDs was performed employing X-ray diffraction (XRD) and transmission electronic microscopy (TEM). Before the deployment of the ZnO QDs thin film layers, the optimal thickness of the PMMA matrix was evaluated by ellipsometry seeking the optimal antireflective effect. The performance characteristics of the solar cells before and after the application of the ZnO/PMMA layers were determined from the J-V curves generated in a solar simulator and their spectral response was evaluated by external quantum efficiency (EQE) measurements achieving a maximum relative PCE increase above 19%.

Efficient and Stable Perovskite Solar Cells Based on Inorganic Hole Transport Materials.

Although power conversion efficiencies of organic-inorganic lead halide perovskite solar cells (PSCs) are approaching those of single-crystal silicon solar cells, the working device stability due to internal and external factors, such as light, temperature, and moisture, is still a key issue to address. The current world-record efficiency of PSCs is based on organic hole transport materials, which are usually susceptible to degradation from heat and diffusion of dopants. A simple solution would be to replace the generally used organic hole transport layers (HTLs) with a more stable inorganic material. This review article summarizes recent contributions of inorganic hole transport materials to PSC development, focusing on aspects of device performance and long-term stability. Future research directions of inorganic HTLs in the progress of PSC research and challenges still remaining will also be discussed.

Measurement and Analysis of Optical Properties of Polymer Films with Triangular Pyramid Optical Functional Texture

A poly (vinyl chloride) film with triangular pyramid array structure was designed and fabricated. In this paper, a plane to plane hot embossing technique is used to fabricate a triangular pyramid antireflection film on the surface of single crystal silicon solar cells. By testing the optical properties of optical functional textured films, it is found that the reflectivity of triangular pyramid textured films obtained by hot embossing is significantly lower than that of smooth flat films; The absorption and antireflection of high light on the film surface are obvious; The photoelectric conversion efficiency of the solar cell is further improved. Triangular pyramid optical functional structure has great potential in improving the performance of silicon solar cells, which can be applied to different types of solar cells. These improvements are of great significance to the commercialization of silicon solar cell devices.

Three Generations of Solar Cells

In photovoltaic system the major challenge is the cost reduction of the solar cell module to compete with those of conventional energy sources. Evolution of solar photovoltaic comprises of several generations through the last sixty years. The first generation solar cells were based on single crystal silicon and bulk polycrystalline Si wafers. The single crystal silicon solar cell has high material cost and the fabrication also requires very high energy. The second generation solar cells were based on thin film fabrication technology. Due to low temperature manufacturing process and less material requirement, remarkable cost reduction was achieved in these solar cells. Among all the thin film technologies amorphous silicon thin film solar cell is in most advanced stage of development and is commercially available. However, an inherent problem of light induced degradation in amorphous silicon hinders the higher efficiency in this kind of cell. The third generation silicon solar cells are based on nano-crystalline and nano-porous materials. Hydrogenated nanocrystalline silicon (nc-Si:H) is becoming a promising material as an absorber layer of solar cell due to its high stability with high Voc. It is also suggested that the cause of high stability and less degradation of certain nc-Si:H films may be due to the improvement of medium range order (MRO) of the films. During the last ten years, organic, polymer, dye sensitized and perovskites materials are also attract much attention of the photovoltaic researchers as the low budget next generation PV material worldwide. Although most important challenge for those organic solar cells in practical applications is the stability issue. In this work nc-Si:H films are successfully deposited at a high deposition rate using a high pressure and a high power by Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RF PECVD) technique. The transmission electron microscopy (TEM) studies show the formations of distinct nano-sized grains in the amorphous tissue with sharp crystalline orientations. Light induced degradation of photoconductivity of nc-Si:H materials have been studied. Single junction solar cells and solar module were successfully fabricated using nanocrystalline silicon as absorber layer. The optimum cell is 7.1 % efficient initially. Improvement in efficiency can be achieved by optimizing the doped layer/interface and using Ag back contact.

Strategies for High-Performance Large-Area Perovskite Solar Cells toward Commercialization

Perovskite solar cells (PSCs) have received a great deal of attention in the science and technology field due to their outstanding power conversion efficiency (PCE), which increased rapidly from 3.9% to 25.5% in less than a decade, comparable to single crystal silicon solar cells. In the past ten years, much progress has been made, e.g. impressive ideas and advanced technologies have been proposed to enlarge PSC efficiency and stability. However, this outstanding progress has always been referred to as small-area (<0.1 cm2) PSCs. Little attention has been paid to the preparation processes and their micro-mechanisms for large-area (>1 cm2) PSCs. Meanwhile, scaling up is an inevitable way for large-scale application of PSCs. Therefore, we firstly summarize the current achievements for high efficiency and stability large-area perovskite solar cells, including precursor composition, deposition, growth control, interface engineering, packaging technology, etc. Then we include a brief discussion and outlook for the future development of large-area PSCs in commercialization.

Effects of 5-Ammonium Valeric Acid Iodide as Additive on Methyl Ammonium Lead Iodide Perovskite Solar Cells.

During the past decade, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has risen rapidly, and it now approaches the record for single crystal silicon solar cells. However, these devices still suffer from a problem of stability. To improve PSC stability, two approaches have been notably developed: the use of additives and/or post-treatments that can strengthen perovskite structures and the use of a nontypical architecture where three mesoporous layers, including a porous carbon backcontact without hole transporting layer, are employed. This paper focuses on 5-ammonium valeric acid iodide (5-AVAI or AVA) as an additive in methylammonium lead iodide (MAPI). By combining scanning electron microscopy (SEM), X-ray diffraction (XRD), time-resolved photoluminescence (TRPL), current–voltage measurements, ideality factor determination, and in-depth electrical impedance spectroscopy (EIS) investigations on various layers stacks structures, we discriminated the effects of a mesoscopic scaffold and an AVA additive. The AVA additive was found to decrease the bulk defects in perovskite (PVK) and boost the PVK resistance to moisture. The triple mesoporous structure was detrimental for the defects, but it improved the stability against humidity. On standard architecture, the PCE is 16.9% with the AVA additive instead of 18.1% for the control. A high stability of TiO2/ZrO2/carbon/perovskite cells was found due to both AVA and the protection by the all-inorganic scaffold. These cells achieved a PCE of 14.4% in the present work.

Design of double‐layer SiN x :H film and its application in c‐Si PERC solar cells

The existing solar cell anti-reflection film technology still cannot adequately meet the light trapping needs of solar cells. In this Letter, double-layered SiN x :H films were prepared for c-Si solar cells by plasma enhanced chemical vapor deposition (PECVD). Herein, the authors introduce a simple, convenient method to lower the reflectance in silicon solar cells by applying double-layered SiN x :H film to increase the refractive index of such film. Compared to the single layer film devices, the reflectance of the double-layered SiN x :H film can be significantly reduced by >30% through enhanced absorption of light in solar cells. This method has achieved an average of 0.08% conversion efficiency, with the highest being 0.18%. In addition, the double-layer film solar cells also showed a better passivation performance than that of the single-layer film, so that the minority carrier lifetime was up to 137 µs. Therefore, the improvement of solar cell efficiency mainly come from the decrease of reflectivity and the improvement in film passivation performance. The work of this Letter demonstrated the light trapping advantages and passivation enhancement performance of double-layer films applied to single crystal silicon solar cells.

Halide Perovskite Epitaxial Heterostructures

ConspectusThe past decade has witnessed the great success and rapid development of halide perovskite materials in photovoltaics and light-emitting devices, which is due to the inherently high photoluminescence quantum yield, long carrier diffusion length, high light absorption coefficient, great defect tolerance, and remarkable tunability. For example, the record efficiency of perovskite solar cells has ramped up to 25.5%, comparable to single-crystal silicon solar cells. In combination with the facile solution processing, perovskite solar cells have gained tremendous attention and interest from both academia and the photovoltaic market. Moreover, as a newly emerging class of semiconductors with excellent properties and low manufacturing cost, it is also promising and meaningful to explore new applications beyond optoelectronic devices, such as transistors, lasers, and memory devices. To this end, the integration of different halide perovskites into epitaxial heterostructures provides an ideal option. On the other hand, from the perspective of fundamental studies, halide perovskite heterostructures also provide a platform to directly visualize ion migration and to study the charge transfer behavior and anomalous exciton phenomena, etc.The aim of our Account is to summarize the synthetic strategies to achieve halide perovskite epitaxial heterostructures and to highlight the effective routes to stabilize halide perovskites and heterostructures. We focus this Account on two-dimensional (2D) halide perovskites and emphasize the important roles the organic ligands play. Specifically, we discuss our recent findings on the incorporation of conjugated organic ligands into 2D halide perovskites leading to enhanced thermal and environmental stability and suppressed halide interdiffusion in the corresponding heterostructures. Molecular dynamics simulation and low-dose aberration corrected transmission electron microscopy were used as powerful tools to unveil and elucidate the working mechanism of stabilization and anion interdiffusion suppression. Following this strategy, diverse halide perovskite heterostructures between different halides, metals, or organic cations and more complex heterostructures and superlattices can be realized. Due to the reduced ion motion and improved stability, the interface of the heterostructures can be kept quite sharp. In the outlook of this Account, we discuss the challenges and a few promising directions with a special focus on the vertical van der Waals (vdW) heterostructures, which are expected to offer more flexibility in heterostructure integration and more opportunities in studying the charge transfer and carrier interaction along the out-of-plane direction. Moreover, the existence of semiconducting organic ligands provides new insights to tune the carrier and exciton behaviors along both in-plane and out-of-plane directions.

Improved Mechanical Durability of High‐Performance OPVs Using Semi‐Interpenetrating Networks

AbstractOrganic photovoltaic (OPV) devices offer a number of unique advantages over conventional single crystal silicon solar cells, such as simple and low‐cost fabrication, significantly reduced weight, high flexibility, and semitransparency. However, OPV devices exhibit poor durability to mechanical deformations. Here, the use of an elastic semi‐interpenetrating network is studied to improve the mechanical durability of the active layer of OPV devices based on the high‐performance poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione)]:2,2′‐[[6,6,12,12‐tetrakis(4‐hexylphenyl)‐6,12‐dihydrodithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐2,8‐diyl]bis[methylidyne(3‐oxo‐1H‐indene‐2,1(3H)‐diylidene)]]bis[propanedinitrile] donor:acceptor blend (PBDBT‐2F:ITIC). The elastic interpenetrating network is synthesized in situ through the UV photoinitiated crosslinking of thiol–ene additives in the active layer. The effects of strain as a function of bending on the network‐stabilized active layer structure are systematically investigated. The elastic interpenetrating network suppresses crack formation and improves durability to high‐curvature and repeated bending deformations. Performance measurements show that network‐stabilized devices outperform pristine devices above a critical bending strain and number of bending deformations. The photovoltaic performance in general decreases with the increase in the network content, and the best performing devices are obtained using network forming reagents that are most compatible with the donor:acceptor system. This work describes an effective route to flexible devices using semi‐interpenetrating polymer networks and provides insight into the design of the networks to maximize photovoltaic performance.

Optical properties of lead-free perovskite Cs2InAg(BrxCl1−x)6 for solar cell applications: A DFT study

Organic-inorganic metal halide perovskites have emerged as promising materials for low-cost, high-efficiency solar cells. Chemical compositional tuning along with different device structures for fabrication and interfacial engineering made the record PCE of perovskite solar-cells reaching 25.2%, which is close to that of single crystal silicon solar cells. We investigated the structural, electronic and optical properties of bromine (Br) doped Cs2InAgCl6 in the cubic phase for various doping percentages. The lattice constants were optimized using Birch Murnaghan fit and band gap were found to be increasing as the doping percentage of Br is increased. The theoretical calculations were performed using generalized gradient approximation exchange correlation for all calculations. The optical properties are studied by comparing the absorption coefficients. Contour plots of charge density shows that the nature of chemical bonding is ionic. Band structure plot along high symmetry points revealed a direct band.

Characterization of Perovskite Solar Cell with Fe3+ Doped TiO₂ Layer.

Recently, single-crystal silicon solar cells have achieved efficiencies of 25%. However, their production is energy-demanding and relatively expensive. Therefore, photovoltaic cells based on organic- inorganic hybrid perovskites have attracted considerable attention owing to their high conversion efficiencies, simple preparation, and potentially low production costs. In this study, we investigated the effect of Fe3+ doped into a compact and mesoporous layer of TiO₂ on the efficiency of the resultant perovskite solar cell (PSC). The efficiencies achieved for PSCs with Fe3+/TiO₂ were higher than those for cells with pure TiO₂ nanoparticles. The samples were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, and current-voltage measurements. The photoelectrode PSC exhibited a high light-to-electric-energy conversion efficiency under a simulated solar light irradiation of 100 mW/cm² (AM 1.5). Our results suggest that Fe3+ nanoparticles in the TiO₂ layer may contribute to the performance improvement of the PSC.

Performance of Single-Crystal Silicon Solar Cells With Mist-Deposited Nanocrystalline Quantum Dot Downshifting Films

The paper is concerned with an investigation of the effect of the mist-deposited downshifting nanocrystalline quantum dots (NQD) films both continuous and patterned on the performance of single-crystal commercial silicon solar cells. Different thicknesses of the NQD films are explored in an attempt to improve cell's efficiency in the ultraviolet (UV) range (below 400 nm) of the solar spectrum. The results obtained indicate that the maximum UV absorption is observed with a 50-nm-thick NQD film as reflected by on the average 45% increase in UV external quantum efficiency as compared with the solar cell without the NQD film. The patterned NQD films are showing improved performance in the visible range as compared with unpatterned NQD films without compromising the performance of the cell in the UV range of the solar spectrum. Also, an increase in power conversion efficiency by 12.5% is observed. Overall, an improvement of silicon solar cells performance using mist deposition of downshifting NQD films instead of spin-on coating as previously explored in other studies is demonstrated.

A new silicon PV record [News

There's a new king of silicon solar cells. Researchers at Kaneka Corp., a resin and plastics manufacturer based in Osaka, have come up with a single-crystal heterojunction silicon solar cell that achieves a record-breaking 26.3 percent efficiency-a 0.7 percent increase over the previous record. That may not seem like a lot, but it's really a big step when you consider that the theoretical maximum efficiency for such cells-which make up about one-quarter of annual global production by gigawatts-is just over 29 percent.

Solar cell efficiency improvement employing down-shifting silicon quantum dots

We report the synthesis and characterization of silicon quantum dots (Si-QDs) that exhibit down-shifting, photo-luminescent characteristics, and the dependence of luminescent characteristics on sodium l-ascorbate, APTES and the reaction time. The synthesized silicon nanostructures were observed to absorb UV photons and subsequently reemit in a broad visible region extending from 450 to 650 nm. The incorporation of these nanostructures as a photon down-shifting layer on solar cells triggered improvements in the performance of the fabricated photovoltaic devices, especially in the open circuit voltage (Voc) and short circuit current density (Jsc). Specifically, the experimental results showed increments in the Voc from 532.6 to 536.2 mV and in the Jsc from 33.4 to 38.3 mA/cm2. The combined effect of those improved Voc and Jsc values led to an increment in the power conversion efficiency (PCE) from 11.9 to 13.4%. This increment represents an improvement of the order of 12.4% on the power conversion efficiency on the silicon solar cells employed. The observed results could be conducive to promoting the proliferation of photovoltaic structures. Additionally, we discuss the fabrication and characterization of the single crystal Silicon (c-Si) Solar cells employed in this exercise.

Enhancement of GdVO 4 :Eu3+ red fluorescence through plasmonic effect of silver nanoprisms on Si solar cell surface

Abstract A comprehensive study on deposition and conjugation of red emitting phosphor (GdVO 4 :Eu 3+ ) and silver nanoprisms (Ag NP) on commercial single crystal silicon solar cell surface has been done to establish the optimum dielectric separating layer (PVA) sequence between consecutive species through confocal fluorescence mapping and spectroscopy. Results show that up to 310% fluorescence enhancement could be achieved in optimal arrangement of emitter, PVA and Ag NP layers on Si cell surface. The current work shows the potential of plasmon enhanced down shifting fluorescence of rare-earth doped vanadate in enhancing performance of SiPV devices.

Structural Stabilities and Electronic Properties of High-Angle Grain Boundaries in Perovskite Cesium Lead Halides

Organometal trihalide perovskites are emerging as very promising photovoltaic materials, which is rivaling that of single crystal silicon solar cells despite their polycrystalline nature with relatively high density of grain boundaries (GBs). There is a lack of understanding of the effects of GBs on halide perovskites as their presence in silicon and other photovoltaic materials is generally detrimental to their photovoltaic properties. Using first-principles calculations, we systematically investigate the geometric structures of high-angle tilt GBs in halide perovskites CsPbX3 (X = Cl, Br, and I) starting from the coincidence site lattice model and refining using crystal shifts and lattice expansion. Electronic density of states calculations reveal that GBs in halides perovskites do not generate midgap states because of the large distance between the unsaturated atoms and the atomic reconstructions in the GB region. However, we show that the GBs can induce different very shallow states near the valence b...

Decrease in power generation efficiency of single crystal silicon solar cell module due to thermal cycling load and extension of crack

Decrease in power generation efficiency of single crystal silicon solar cell module due to thermal cycling load and extension of crack

Enhancing the power conversion efficiency of solar cells employing down-shifting silicon quantum dots

We report the synthesis and characterization of silicon quantum dots that exhibit down-shifting, photo luminescent characteristics. We also discuss the fabrication and characterization of single crystal Silicon (c-Si) Solar cells with and without the influence of the previously mentioned QDs. The incorporation of these nanostructures triggers improvements in the performance of the fabricated photovoltaic devices, especially in the open circuit voltage (Voc) and short circuit current density (Jsc). Specifically, the experimental results showed increments in the Voc from 532.6 to 536.2 mV and in the Jsc from 33.4 to 38.3 mA/cm2. The combined effect of those improved Voc and Jsc values led to an increment in the power conversion efficiency (PCE) from 11.90 to 13.37%. This increment represents an improvement of the order of 12.4% on the power conversion efficiency of this type of solar cells. The observed results could be conducive to promoting the proliferation of photovoltaic structures.