Photovoltaic Solar Energy Generation

Rhodes, William T.; Asakura, Toshimitsu; Brenner, Karl‐Heinz; Hänsch, Theodor W.; Kamiya, Toshio; Krausz, Ferenc; Ḿonemar, B.; Venghaus, H.; Weber, Horst; Weinfurter, Harald

doi:10.1007/b137803

Cited by 49 publications

(2 citation statements)

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“…5. This ( 8) observation was stated by Goetzberger & Hoffmann [13] when comparing the irradiation in Khartoum and Freiburg, southern Germany. Figure 5 shows an almost constant output power indicated by (Y f,m ) through the year, with 0.21 standard deviation from its mean value and low seasonal index of 1.2.…”

Section: Resultssupporting

confidence: 52%

Impact of high temperature on PV productivity in hot desert climates

Hashim

Hassan²

2022

GRN TECH RES SUSTAIN

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Hot dry climate regions enjoy high solar irradiation, albeit with high ambient temperatures. These two factors have a contradictory effect on the power generated from PV systems. This work studies the combined effect of high ambient temperature and high irradiation on the net performance of PV systems. The study is based on monitoring a grid-connected 5 kW PV system installed on the rooftop of the Energy Research Center of the University of Khartoum, Sudan. The performance was monitored by meteorological and power measurement equipment from April 2017 to March 2018. The results showed stable power output from the PV system with an average final yield of 4.57 kWh/kWp and a 0.21 standard deviation from this average value. The stability in power output is due to the compensation of the efficiency degradation due to high temperature by high irradiation in summer. This is combined with the relatively low irradiation in winter compensated by the low temperature effect in winter. The annual deviation of the temperature and irradiation is small in Khartoum due to its proximity to the equator. The semi desert climate, offers Khartoum notably few annual cloudy hours. These characteristics were compared with the annual performance of other countries with different climates. The conclusion from this work on hot dry regions is that despite the negative effect of temperature, the annual output power from the system tends to be stable due to the substitution contributed by the regionally high radiation and the relatively cool winter climate.

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Section: Resultssupporting

confidence: 52%

Impact of high temperature on PV productivity in hot desert climates

Hashim

Hassan²

2022

GRN TECH RES SUSTAIN

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“…Solar energy presents a viable solution to the pressing issue of global warming induced by CO 2 emission from conventional sources, such as coal and fossil fuels . It can be converted into electric energy in solar cells, which still pose interesting challenges.…”

Section: Introductionmentioning

confidence: 99%

Structural Features and Optical Properties of All-Inorganic Zero-Dimensional Halides Cs₄PbBr_6–xI_x Obtained by Mechanochemistry

Abia,

López,

Gainza

et al. 2023

ACS Appl. Mater. Interfaces

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Despite the great success of hybrid CH 3 NH 3 PbI 3 perovskite in photovoltaics, ascribed to its excellent optical absorption properties, its instability toward moisture is still an insurmountable drawback. All-inorganic perovskites are much less sensitive to humidity and have potential interest for solar cell applications. Alternative strategies have been developed to design novel materials with appealing properties, which include different topologies for the octahedral arrangements from three-dimensional (3D, e.g., CsPbBr 3 perovskite) or two-dimensional (2D, e.g., CsPb 2 Br 5 ) to zero-dimensional (0D, i.e., without connection between octahedra), as the case of Cs 4 PbX 6 (X = Br, I) halides. The crystal structure of these materials is complex, and their thermal evolution is unexplored. In this work, we describe the synthesis of Cs 4 PbBr 6−x I x (x = 0, 2, 4, 6) halides by mechanochemical procedures with green credentials; these specimens display excellent crystallinity enabling a detailed structural investigation from synchrotron X-ray powder diffraction (SXRD) data, essential to revisit some features in the temperature range of 90−298 K. In all this regime, the structure is defined in the trigonal R3̅ c space group (#167). The presence of Cs and X vacancies suggests some ionic mobility into the crystal structure of these 0D halides. Bond valence maps (BVMs) are useful in determining isovalent surfaces for both Cs 4 PbBr 6 and Cs 4 PbI 6 phases, unveiling the likely ionic pathways for cesium and bromide ions and showing a full 3D connection in the bromide phase, in contrast to the iodide one. On the other hand, the evolution of the anisotropic displacement parameters is useful to evaluate the Debye temperatures, confirming that Cs atoms have more freedom to move, while Pb is more confined at its site, likely due to a higher covalency degree in Pb−X bonds than that in Cs−X bonds. Diffuse reflectance ultraviolet−visible (UV−vis) spectroscopy shows that the optical band gap can be tuned depending on iodine content (x) in the range of 3.6−3.06 eV. From density functional theory (DFT) simulations, the general trend of reducing the band gap when Br is replaced by I is well reproduced.

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