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[en] An inverted bulk heterojunction organic photovoltaic device based on blend of conjugated polymers and fullerenes derivatives with Cs2CO3/PVDF composites as an electron transporting layer. The entire device structure ((Cs2CO3/PVDF)/P3HT: PCBM/V2O5/Al) has been fabricated using spin coating method and the final metal contact was made using thermal evaporation technique. The mol % of Cs2CO3: PVDF ratio and the spin rate of electron transport and P3HT:PCBM was subjected to be varied and its device performance were evaluated using solar simulator under one sun condition. The physio-chemical characterizations such as UV-Visible, FTIR, PL, XRD, FESEM and AFM were performed for all the materials used in the device fabrications. By varying the spin rate of conjugated polymers/fullerene blends it may helps in scaling up of self-organized molecules of an active layer. Also the variation of spin rate will plays a role in the surface roughness of the film and thereby contributing enhancing the photo-conversion efficiency of fabricated devices. The device fabricated with optimized conditions under ambient atmosphere exhibits efficiency of 1.8 % with JSC of 5.8 mA/cm2 and VOC of 0.57 V. The performance of the device can be enhanced further by controlling exposure of electrode materials. (author)
[en] The structural, optical, and optoelectronic properties of copper zinc tin sulfide (CZTS) films, deposited by a nonvacuum nanoparticle based approach were studied as a function of different annealing temperatures. The CZTS films for photovoltaic applications were deposited using the doctor blading method using an ink prepared with nanoparticles synthesized using the solvothermal method. Deposited films were annealed at different temperatures in N2-S atmosphere. The films were characterized using different tools such as X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), ultraviolet-visible spectroscopy, Raman spectroscopy, and photoconductivity. The results showed that the kesterite phase was formed in the temperature range between 400 and 550 oC. At temperatures beyond 500 oC, many peaks of binary and ternary phases were detected, probably because of the decomposition of the kesterite layer. The cross section SEM images showed that the film is compact; however, there are isolated voids. The EDXS estimated chemical composition was found to vary with annealing temperature; the nearly stoichiometric film was obtained when annealed at 450 oC. The optical band gap of the stoichiometric film was 1.6 eV, and it showed photoconductivity. (author)
[en] Designing PV-hybrid systems requires to obtain the best PV panels and batteries, in order to ensure the electrical energy consumers for a certain geographic region. An efficiency coefficient is suggested, which assesses the efficiency of the designed PV-hybrid system, without taking into consideration the economical aspects. After the PV modules and batteries are chosen for optimal efficiency coefficient, an economical assessment is made. The method is applied on a medium sized consumer (poultry farm) for a time interval of several years for the geographical location of Ruse, Bulgaria. Keywords: efficiency, PV-hybrid, design, sizing.
[en] We examine the dependence of the crystalline volume fraction on the mean crystallite size for hydrogenated nanocrystalline silicon based photovoltaic solar cells; this work builds upon an earlier study by Schmidt et al. (Mater. Res. Soc. Symp. Proc. 1536 (2013)). For each photovoltaic solar cell considered, the X-ray diffraction and Raman spectra are measured. Through the application of Scherrer's equation, the X-ray diffraction results are used to determine the corresponding mean crystallite sizes. Through peak decomposition, the Raman results are used to estimate the corresponding crystalline volume fraction. Plotting the crystalline volume fraction as a function of the mean crystallite size, it is found that larger mean crystallite sizes tend to favor reduced crystalline volume fractions. The ability to randomly pack smaller crystallites with a greater packing fraction than their larger counterparts was suggested as a possible explanation for this observation. (author)
[en] India is blessed with good solar resources and many regions of the country receive above-average sunshine compared to other regions of the world. The primary technology used for harnessing and converting solar energy into electrical energy in India is based on photovoltaic (PV) cells. Concentrated solar power (CSP) has hardly contributed to the overall installed solar power capacity in the country. In this article, some of the challenges that have inhibited the growth of CSP are identified and possible solutions suggested. The critical challenges for CSP are related to the lack of reliable direct normal irradiance database, indigenous manufacturing and competition from PV. The results of a case study carried out to assess the impact of indigenous manufacturing and economies of scale on capital costs and levelized cost of electricity are presented. This study shows that even with indigenous manufacturing and considering economies of scale, the capital cost per MW (Megawatt) of installed capacity is higher than the Central Electricity Regulatory Commission benchmark costs. To initiate larger adoption of CSP in India, we may have to consider alternative configurations, such as coupling desalination or thermal cooling systems to a CSP power plant. The merits of such configurations, called poly-generation plants, are presented for the Indian scenario. (author)
[en] High-performance solar-cell is designed for lead-free perovskite materials, synthesis of using for the organometallic halides. The perovskite materials having a high-efficiency charge carrier and identified low - cost materials based commercial photo - voltaic cell. It is an unusually breakthrough of the drawback of high - efficiency photo - voltaic solar - cell because in this solar - cell replaced harmful lead using various perovskite materials like (Sn2+, Ge2+, Mg2+, Ca2+, Sr2+, Ba2+, Cu2+, Fe2+, Pd2+, and Eu2+). We predict the structure and optical properties of perovskite solar - cell based on Ge and Sn solid solutions, CH3NH3Sn(1−x)GexI3 (0 ≤ x ≤ 1). This material is having the band gaps from 1.3 to 2.0 eV, and it is suitable for an optoelectronic application's range, from single junction devices and top cells for placement to light - emitting layer. The power efficiency of lead - free perovskite solar - cell (LFPSCs) is more than 27%. Which has ABO3 type orthorhombic crystal structure and successfully examine its structure using X-ray diffraction (XRD) technology. In this research, we synthesis successfully lead - free perovskite solar - cell (LFPSCs). (author)
[en] Harnessing renewable solar energy through different technologies is greatly dependent on the advancement of solar grade materials’ science and engineering. In this article, the prominent solar energy technologies, namely solar photovoltaic and concentrated solar power and other relevant technologies, and aspects related to various solar grade materials, influence of nanomaterials on enhancement of solar energy harvest, technology–market relations, development of hybrid systems etc., are discussed. The inspiration to write this article is not only to review the existing technologies to harvest solar energy but also to highlight the pertinent and possible solutions thereof, especially from materials perspective.
[en] The effect of single-walled carbon nanotube (SWNT) incorporation within bulk heterojunction photovoltaic devices based on poly(3-hexylthiophene) - [6,6]-phenyl-C61-butyric acid methyl ester (P3HT-PCBM) (1:1 w/w) active layers was investigated. Both full-length and shortened SWNTs were introduced within the P3HT-PCBM layer at loadings in the range of 0-2 wt%. For full-length SWNTs, it was found that device efficiency decreased at all SWNT loading levels and annealing temperatures, which ranged from 80 to 225 oC. The highest average external efficiencies in the absence of SWNTs reached approximately 2%, while the best efficiencies in devices incorporating the full-length SWNTs only reached 1.3%. When shortened SWNTs were incorporated, device efficiency was unchanged upon annealing at 160 oC (average values of approximately 2%), but the efficiency improved by nearly 50%, relative to controls when devices were annealed at 70 oC. Active layer analysis by grazing incidence X-ray diffraction indicated that nanotubes did not increase polymer crystallinity. Knowing that shortened SWNTs are good hole conductors, it is postulated that the improved device efficiency is due to improved hole transport through the SWNTs in devices where the hole-transporting polymer has not been allowed to adopt its optimal morphology due to underannealing. (author)