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Aims to present a methodology for analysing a solar‐electric, high‐altitude, long‐endurance, unmanned aircraft.

The study focuses on the aerodynamics, flight performance and power requirements of a heavier‐than‐air, solar‐electric, HALE UAV. The methodology is founded on using an analytical approach to determine the power required to undertake various flight manoeuvres. An analytical approach is also undertaken in determining the intensity of the solar radiation available to the aircraft. Finally to demonstrate the methodology, a HALE concept was generated and evaluated.

When using estimates of current solar‐electric propulsion and energy conversion efficiencies, the HALE concept was only able to sustain year round, level flight up to latitudes of 10°N.

Further analysis needs to be undertaken into the effect of altitude on the intensity of solar radiation, which could be as much as 25 per cent higher at an altitude of 21.3 km (70,000 ft). Further study into this subject area may provide proof that sustained flight is possible at more northerly latitudes.

This paper provides a simple methodology for persons wishing to undertake an initial feasibility study of a solar‐electric HALE concept.

In the past several years, CH₃NH₃PbI₃ perovskite material has been extensively evaluated as an absorber layer of perovskite solar cells due to its excellent structural and optical properties, and greater than 22% conversion efficiency. However, improvement and future commercialization of solar cells based on CH₃NH₃PbI₃ encountered restrictions due to toxicity and instability of the lead element. Recently, studies on properties of lead-free and mixture of lead with other cations perovskite thin films as light absorber materials have been reported. The purpose of this paper was the fabrication of CH₃NH₃Sn₁-xPbxI₃ thin films with different SnI₂ concentrations in ambient condition, and study on the structural, morphological, optical, and photovoltaic performance of the studied solar cells. The X-ray diffraction studies revealed the formation of both CH₃NH₃PbI₃ and CH₃NH₃SnI₃ phases with increasing the Sn concentration, and improvement in crystallinity and morphology was also observed. All perovskite layers had a relatively high absorption coefficient >104 cm⁻¹ in the visible wavelengths, and the bandgap values varied in the range from 1.46 to 1.63 eV. Perovskite solar cells based on these thin films have been fabricated, and device performance was investigated. Results showed that photo-conversion efficiency (PCE) for the pure CH₃NH₃PbI₃sample was 1.20%. With adding SnI₂, PCE was increased to 4.48%.

In this work, the author mixed tin and lead with different percentages in the perovskite thin film. Also, the preparation of these layers and also other layers to fabricate solar cells based on them were conducted in an open and non-glove box environment. Finally, the effect of [Sn/Pb] ratio in the CH₃NH₃Sn₁-xPbxI₃ layers on the structural, morphological, optical, electrical and photovoltaic performance have been investigated.

CH₃NH₃Sn₁-xPbxI₃ (x = 0.0, 0.25, 0.50, 0.75, 1.0) perovskite thin films have been grown by a spin-coating technique. It was found that as tin concentration increases, the X-ray diffraction and FESEM images studies revealed the formation of both CH₃NH₃PbI₃ and CH₃NH₃SnI₃ phases, and improvement in crystallinity, and morphology; all thin films had high absorption coefficient values close to 104 cm⁻¹ in the visible region, and the direct optical bandgap in the layers decreases from 1.63 eV in pure CH₃NH₃SnI₃ to 1.46 eV for CH₃NH₃Sn0.0.25Pb0.75I3 samples; all thin films had p-type conductivity, and mobility and carrier density increased; perovskite solar cells based on these thin films have been fabricated, and device performance was investigated. Results showed that photo-conversion efficiency (PCE) for the pure CH₃NH₃PbI₃sample was 1.20%. With adding SnI2, PCE was increased to 4.48%.

The preparation method seems to be interesting as it is in an ambient environment without the protection of nitrogen or argon gas.

This paper presents an experimental investigation of photovoltaic (PV) properties in heterostructures consisting of indium oxide and amorphous silicon thin films, grown on a single crystalline p-type silicon and polyimide flexible substrates. Both thin films: In₂O₃ and a-Si were deposited by magnetron sputtering. Such heterostructure thin film systems are attractive because of their ability to convert solar energy into electrical one. Grown Heterostructures films were treated by simultaneous influence of an electron beam and high energetic photons with energy more than 1.5 eV in the so called vacuum photo-thermal processing (VPP).

Silicon samples of 100 Ω/sq and 45 Ω/sq were selected as substrates. Thin films deposition was done in argon atmosphere by DC magnetron sputtering.

It is shown that:

Open circuit voltage of the proposed structure may reach up to ~ 0.35 V,

Short circuit current was of no more then 10-7 A,

Polyimide materials may be used as substrates for PV thin film deposition structures,

VPP dramatically varies the photovoltaic properties of the heterostructure

The purpose of this paper is to study the optical and electrical characteristics of a single-junction solar cell based on a green-colour dye vanadyl 2,9,16, 23-tetraphenoxy-29H, 31H-phthalocyanine (VOPcPhO). The use of soluble vanadyl phthalocyanine derivative makes it very attractive for photovoltaic applications due to its tunable properties and high solubility.

A photoactive layer of VOPcPhO has been sandwiched between indium tin oxide (ITO) and aluminium (Al) electrodes to produce a ITO/PEDOT:PSS/VOPcPhO/Al photovoltaic device. The VOPcPhO thin film is deposited by a simple spin coating technique. To obtain the optimal thickness for the solar cell device, different thicknesses of the photoactive layer, achieved by manipulating the spin rate, have been investigated.

The device exhibited photovoltaic effect with the values of Jsc, Voc and FF equal to 5.26 × 10-6 A/cm2, 0.621 V and 0.33, respectively. The electronic parameters of the cell have been obtained from the analysis of current-voltage characteristics measured in dark. The values of ideality factor and barrier height were found to be 2.69 and 0.416 eV, respectively. The optical examination showed that the material is sensitive to light in the UV region between 270 nm and 410 nm, as well as in the visible spectrum within the range of 630 nm and 750 nm.

The solar cell based on a single layer of vanadyl phthalocyanine derivative results in low efficiency, which can be enhanced by introducing a variety of donor materials to form bulk heterojunction solar cells.

The spin coating technique provides a simple, less expensive and effective approach for preparing thin films.

A novel thin-film, single-junction organic solar cell, fabricated by using VOPcPhO, has been investigated for the first time ever. The vanadyl phthalocyanine derivative together with a donor material will have potential application for improved efficiency of the solar cells.

This study aims to propose a methodology by integrating three approaches, namely, internal core technology, external knowledge flow and industrial technology development to help companies improve their decision-making quality for technology planning and enhance their research and development (R&D) portfolio efficiency.

The primary focus of this study is thin-film solar technology and patent data is retrieved from the United States Patent and Trademark Office (USPTO) database. This study presents a methodology based on the proposed integrated analysis method, constructed with patent indicators, centrality analysis of social networks and main path analysis.

The results of this study can be itemized as – the core technological competency: companies involved in two specific technology fields have lower strength in R&D portfolio than leading companies with single-core technology. Knowledge flow: most companies in a network are knowledge producers/absorbers and technological development: diverse source and sink nodes were identified in the global main path during 1997-2003, 2004-2010 and 2011-2017.

Latecomer companies can emulate leaders’ innovation and enhance their technological competence to seek niche technology. Using the global main path, companies monitor outdated technologies that can be replaced by new technologies and aid to plan R&D strategy and implement appropriate strategic decisions avoiding path dependency.

The knowledge accumulation process helps in identifying the change of position and the role of companies; understanding the trend of industrial technology knowledge helps companies to develop new technology and direct strategic decisions. The novelty of this research lies in the integrated approach of three methods aiding industries to find their internal core technical competencies and identify the external position in the competitive market.

The purpose of this paper is to investigate the potential of the experimental building integrated photovoltaic (BIPV) façade to cover net energy use in the adjacent office room. Electricity generated by PV panels was intended to cover the energy demand for the mechanical ventilation and the supplementary lighting. Analyses were performed for two orientations of the façade (east and west) and two occupancy profiles considering one or two employees per one office room.

The study was conducted by carrying detailed numerical analyses of energy produced by the BIPV façade and its consumption in adjacent office room. Calculations of energy generated by PV panels were made using simulation programme ESP-r. Advanced model, used in analyses, take into account dependence of the main electrical parameters of photovoltaic cell from temperature.

The findings reveal that energy generated by photovoltaic panels during transitional and cooling seasons is sufficient for lighting and ventilation requirement. However during winter months BIPV facade can cover energy demand only for ventilation.

The paper provides an original analysis of experimental BIPV façade system as a source of on-site produced renewable energy to cover energy demand in offices building under certain climate conditions. The results reported in presented paper shows the potential of BIPV facades and display this potential in a context of building net energy balance.

The purpose of this paper is to explore the use of the purchase power of the higher education system to catalyze the economy of scale necessary to ensure market competitiveness for solar photovoltaic electricity.

The approach used here was to first determine the demand necessary to construct “Solar City factories”, factories that possess equipment and processes sized, dedicated and optimized to produce only solar photovoltaic systems. Inexpensive solar cells from these factories could produce solar electricity at rates comparable to conventional fossil‐fuel derived electricity. Then it was determined if sufficient demand could be guaranteed by green purchasing from the international university system.

A focused effort from the university community to purchase on‐sight produced electricity would make it possible to construct truly large‐scale dedicated solar photovoltaic factories rather than follow the piecemeal production increases currently observed in the industry.

Direct economic competitiveness of an energy source having markedly lower environmental, social and health externalities would have a positive‐spiral (virtuous cycle) effect encouraging the transition of the global energy infrastructure away from polluting fossil fuels to green solar energy.

Despite significant commercial progress in the conversion efficiency of sunlight into electricity with solar photovoltaic cells, their widespread adoption is still limited by high costs relative to conventional fossil fuel‐based sources of electricity. The concept outlined and critically reviewed in this paper represents a novel and economical method of transitioning the electric supply system to renewable solar energy.

This article reflects an analysis of the energy issues tackled in national foresight studies to date. The energy sector has not been explicitly mentioned in some of the studies but it is integrated in other sectors. What follows is a summary of the issues on which the different foresight studies are focused. The summary includes the most important topics affecting energy‐related issues for the panel of experts of each country. The article shows, first, a group of general considerations specific for each country. It then shows the types of technologies which have been considered in each foresight study. Finally, before drawing conclusions, it provides a technology table from which it is possible to see which energy technologies have been considered as important in each country.

The purpose of this study is to design and optimize copper indium gallium selenide (CIGS) thin film solar cells.

A novel bi-layer CIGS thin film solar cell based on SnS is designed. To improve the performance of the CIGS based thin film solar cell a tin sulfide (SnS) layer is added to the structure, as back surface field and second absorbing layer. Defect recombination centers have a significant effect on the performance of CIGS solar cells by changing recombination rate and charge density. Therefore, performance of the proposed structure is investigated in two stages successively, considering typical and maximum reported trap density for both CIGS and SnS. To achieve valid results, the authors use previously reported experimental parameters in the simulations.

First by considering the typical reported trap density for both SnS and CIGS, high efficiency of 36%, was obtained. Afterward maximum reported trap densities of 1 × 10¹⁹ and 5.6 × 10¹⁵cm⁻³ were considered for SnS and CIGS, respectively. The efficiency of the optimized cell is 27.17% which is achieved in CIGS and SnS thicknesses of cell are 0.3 and 0.1 µm, respectively. Therefore, even in this case, the obtained efficiency is well greater than previous structures while the absorbing layer thickness is low.

Having results similar to practical CIGS solar cells, the impact of the defects of SnS and CIGS layers was investigated. It was found that affixing SnS between CIGS and Mo layers causes a significant improvement in the efficiency of CIGS thin-film solar cell.