• Energy Research

Dans les cellules solaires à couche mince, la productivité de conversion du photocourant peut être nettement augmentée à l'aide d'un réflecteur arrière approprié. Ici, l'impact de différents réflecteurs arrière lisses et texturés a été exploré et réalisé pour étudier les phénomènes optiques avec des stratégies d'ingénierie d'interface et des caractéristiques de contacts transparents. Un type unique de masque de gravure 3D de substrat de verre texturé chimiquement humide utilisé dans une cellule solaire à base de silicium amorphe superstrat (p–i–n) avec un réflecteur arrière légitimé permet de rejoindre les méthodologies de piégeage de la lumière standard, qui sont utilisées pour améliorer l'efficacité de conversion d'énergie (ECE). Pour étudier les propriétés optiques et électriques de la structure des cellules solaires, les simulations optiques dans des mesures tridimensionnelles (3D) ont été effectuées en utilisant la technique du domaine temporel à différence finie (FDTD). Cette méthodologie de conception permet de déterminer les pertes de puissance, les rendements quantiques et les densités de courant de court-circuit de diverses couches dans une telle cellule solaire. Les densités de courant de court-circuit pour différents réflecteurs ont été variées de 11,50 à 13,27 et de 13,81 à 16,36 mA/cm2 pour les cellules solaires texturées lisses et pyramidales, individuellement. Contrairement à la cellule de référence plate comparable, la densité de courant de court-circuit de la cellule solaire texturée a été augmentée d'environ 24 %, et les rendements quantiques externes les plus extrêmes sont passés de 79 à 86,5 %. L'absorption des photons a été fondamentalement améliorée dans la région spectrale de 600 à 800 nm sans diminution du photocourant de longueur d'onde inférieure à 600 nm. Par conséquent, ces conceptions optimisées aideront à construire les plans efficaces de la prochaine génération de cellules solaires à base de silicium amorphe. En las células solares de película delgada, la productividad de conversión de fotocorriente se puede aumentar claramente utilizando un reflector posterior adecuado. Aquí, se exploró y efectuó el impacto de diferentes reflectores traseros lisos y texturizados para estudiar los fenómenos ópticos con estrategias de ingeniería de interfaz y características de contactos transparentes. Un tipo único de máscara de grabado 3D de sustrato de vidrio con textura química húmeda utilizada en la célula solar basada en silicio amorfo superestrato (p–i–n) junto con un reflector posterior legitimado permite unirse a las metodologías estándar de captura de luz, que se utilizan para mejorar la eficiencia de conversión de energía (ECE). Para investigar las propiedades ópticas y eléctricas de la estructura de la célula solar, las simulaciones ópticas en mediciones tridimensionales (3D) se realizaron utilizando la técnica de dominio de tiempo de diferencia finita (FDTD). Esta metodología de diseño permite determinar las pérdidas de potencia, las eficiencias cuánticas y las densidades de corriente de cortocircuito de varias capas en dicha célula solar. Las densidades de corriente de cortocircuito para diferentes reflectores variaron de 11.50 a 13.27 y de 13.81 a 16.36 mA/cm2 para las células solares de textura lisa y piramidal, individualmente. En contraste con la célula de referencia plana comparable, la densidad de corriente de cortocircuito de la célula solar texturizada aumentó en alrededor del 24%, y las eficiencias cuánticas externas más extremas aumentaron del 79 al 86,5%. La absorción de fotones se mejoró fundamentalmente en la región espectral de 600 a 800 nm sin disminución de la fotocorriente más corta que la longitud de onda de 600 nm. Por lo tanto, estos diseños optimizados ayudarán a construir los planes efectivos de células solares basadas en silicio amorfo de próxima generación. In thin-film solar cells, the photocurrent conversion productivity can be distinctly boosted-up utilizing a proper back reflector. Herein, the impact of different smooth and textured back reflectors was explored and effectuated to study the optical phenomena with interface engineering strategies and characteristics of transparent contacts. A unique type of wet-chemically textured glass-substrate 3D etching mask used in superstrate (p–i–n) amorphous silicon-based solar cell along with legitimated back reflector permits joining the standard light-trapping methodologies, which are utilized to upgrade the energy conversion efficiency (ECE). To investigate the optical and electrical properties of solar cell structure, the optical simulations in three-dimensional measurements (3D) were performed utilizing finite-difference time-domain (FDTD) technique. This design methodology allows to determine the power losses, quantum efficiencies, and short-circuit current densities of various layers in such solar cell. The short-circuit current densities for different reflectors were varied from 11.50 to 13.27 and 13.81 to 16.36 mA/cm2 for the smooth and pyramidal textured solar cells, individually. Contrasted with the comparable flat reference cell, the short-circuit current density of textured solar cell was increased by around 24%, and most extreme outer quantum efficiencies rose from 79 to 86.5%. The photon absorption was fundamentally improved in the spectral region from 600 to 800 nm with no decrease of photocurrent shorter than 600-nm wavelength. Therefore, these optimized designs will help to build the effective plans next-generation amorphous silicon-based solar cells. في الخلايا الشمسية ذات الأغشية الرقيقة، يمكن تعزيز إنتاجية التحويل الضوئي بشكل واضح باستخدام عاكس خلفي مناسب. هنا، تم استكشاف تأثير مختلف عاكسات الظهر الملساء والمنسوجة وتنفيذها لدراسة الظواهر البصرية مع استراتيجيات هندسة الواجهة وخصائص الملامسات الشفافة. يسمح نوع فريد من قناع النقش ثلاثي الأبعاد المصنوع من الزجاج المبلل كيميائيًا المستخدم في الخلايا الشمسية غير المتبلورة المصنوعة من السيليكون (p - i - n) جنبًا إلى جنب مع العاكس الخلفي الشرعي بالانضمام إلى منهجيات محاصرة الضوء القياسية، والتي تستخدم لرفع كفاءة تحويل الطاقة (ECE). للتحقيق في الخصائص البصرية والكهربائية لهيكل الخلايا الشمسية، تم إجراء المحاكاة البصرية في القياسات ثلاثية الأبعاد (3D) باستخدام تقنية النطاق الزمني للاختلاف المحدود (FDTD). تسمح منهجية التصميم هذه بتحديد خسائر الطاقة والكفاءات الكمية وكثافات تيار الدائرة القصيرة للطبقات المختلفة في هذه الخلية الشمسية. تفاوتت كثافات تيار الدائرة القصيرة للعاكسات المختلفة من 11.50 إلى 13.27 ومن 13.81 إلى 16.36 مللي أمبير/سم 2 للخلايا الشمسية الملساء والهرمية، بشكل فردي. وعلى النقيض من الخلية المرجعية المسطحة المماثلة، زادت كثافة تيار الدائرة القصيرة للخلية الشمسية المزخرفة بنحو 24 ٪، وارتفعت معظم الكفاءات الكمية الخارجية المتطرفة من 79 إلى 86.5 ٪. تم تحسين امتصاص الفوتون بشكل أساسي في المنطقة الطيفية من 600 إلى 800 نانومتر مع عدم وجود انخفاض في طول الموجة الضوئية أقصر من 600 نانومتر. لذلك، ستساعد هذه التصميمات المحسنة في بناء الخطط الفعالة للجيل التالي من الخلايا الشمسية غير المتبلورة القائمة على السيليكون.

AbstractA chemically treated luffa sponge (LS) derived from the ripe fruit of the Luffa cylindrica (LC) plant is investigated as an efficient solar photothermal conversion material for water purification applications for the very first time. Hydrophilicity and solar absorbance of the LS are enhanced by dopamine treatment and candle soot surface coating. The fabricated surface modified LS (SM‐LS) leads to a superb solar evaporation rate of water as high as 1.30 kg m−2 h−1, which is five times higher than that of the freshwater under 1 sun illumination. The outdoor experiment shows an excellent solar evaporation efficiency of 79.98%, which is significantly higher than other low‐cost materials. Such SM‐LS can be further applied to desalinate seawater, where it is shown that 1 m2 of surface‐modified LS can produce 7.5–8 L of freshwater per day. Hence, the proposed system can be utilized in remote areas and refugee camps.

AbstractLight trapping and photon management in honeycomb‐textured microcrystalline silicon solar cells are investigated experimentally and by modeling of the manufacturing process and the optical wave propagation. The solar cells on honeycomb‐textured substrates exhibit short circuit current densities exceeding 30 mA/cm2 and energy conversion efficiencies of up to 11.0%. By controlling the fabrication process, the period and height of the honeycomb‐textured substrates are varied. The influence of the honeycomb substrate morphology on the interfaces of the individual solar cell layers and the quantum efficiency is determined. The optical wave propagation is calculated using 3D finite difference time domain simulations. A very good agreement between the optical simulation and experimental results is obtained. Strategies are discussed on how to increase the short circuit current density beyond 30 mA/cm2. In particular, the influence of plasmonic losses of the textured silver (Ag) reflector on the short circuit current and quantum efficiency of the solar cell is discussed. Finally, solar cell structures with reduced plasmonic losses are proposed. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract The short-circuit current density and energy conversion efficiency of single-junction perovskite and perovskite/perovskite tandem solar cells can be increased by photon management. In this study, optical metasurfaces were investigated as potential light trapping structures oppose to commonly used pyramidal surface textures. Herein, metal oxide-based non-resonant metasurfaces were investigated as potential light-trapping structures in perovskite solar cells. The zinc oxide nanowire-based building blocks of the metasurface can be prepared by a templated electrodeposition through a mask of resist. The phase of the incident light can be controlled by the edge length of the subwavelength large zinc oxide nanowires. An array of zinc oxide nanowires was prepared and characterized in the current study. Three-dimensional (3D) finite-difference time-domain (FDTD) optical simulations were used to compare solar cells covered with non-resonant metasurfaces with commonly used light trapping structures. As compared to the solar cells covered with zinc oxide pyramid surface texture, solar cells with the integrated non-resonant metasurfaces exhibit almost identical quantum efficiencies and short-circuit current densities. Investigations of such metasurfaces will not only improve the photon absorption in perovskite solar cells but also reveal a pathway to make high-efficiency next-generation solar cells. Detailed guidelines for the realization of non-resonant metal oxide metasurfaces will be provided.

Tungsten oxide (WOx) thin films were synthesized through the RF magnetron sputtering method by varying the sputtering power from 30 W to 80 W. Different investigations have been conducted to evaluate the variation in different morphological, optical, and dielectric properties with the sputtering power and prove the possibility of using WOx in optoelectronic applications. An Energy Dispersive X-ray (EDX), stylus profilometer, and atomic force microscope (AFM) have been used to investigate the dependency of morphological properties on sputtering power. Transmittance, absorbance, and reflectance of the films, investigated by Ultraviolet-Visible (UV-Vis) spectroscopy, have allowed for further determination of some necessary parameters, such as absorption coefficient, penetration depth, optical band energy gap, refractive index, extinction coefficient, dielectric parameters, a few types of loss parameters, etc. Variations in these parameters with the incident light spectrum have been closely analyzed. Some important parameters such as transmittance (above 80%), optical band energy gap (~3.7 eV), and refractive index (~2) ensure that as-grown WOx films can be used in some optoelectronic applications, mainly in photovoltaic research. Furthermore, strong dependencies of all evaluated parameters on the sputtering power were found, which are to be of great use for developing the films with the required properties.