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A surfactant‐free solution methodology, simply using water as a solvent, has been developed for the straightforward synthesis of single‐phase orthorhombic SnSe nanoplates in gram quantities. Individual nanoplates are composed of {100} surfaces with {011} edge facets. Hot‐pressed nanostructured compacts (E g≈0.85 eV) exhibit excellent electrical conductivity and thermoelectric power factors (S 2 σ) at 550 K. S 2 σ values are 8‐fold higher than equivalent materials prepared using citric acid as a structure‐directing agent, and electrical properties are comparable to the best‐performing, extrinsically doped p‐type polycrystalline tin selenides. The method offers an energy‐efficient, rapid route to p‐type SnSe nanostructures.

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The accumulation of soiling on photovoltaic (PV) modules affects PV systems worldwide. Soiling consists of mineral dust, soot particles, aerosols, pollen, fungi and/or other contaminants that deposit on the surface of PV modules. Soiling absorbs, scatters, and reflects a fraction of the incoming sunlight, reducing the intensity that reaches the active part of the solar cell. Here, we report on the comparison of naturally accumulated soiling on coupons of PV glass soiled at seven locations worldwide. The spectral hemispherical transmittance was measured. It was found that natural soiling disproportionately impacts the blue and ultraviolet (UV) portions of the spectrum compared to the visible and infrared (iR). Also, the general shape of the transmittance spectra was similar at all the studied sites and could adequately be described by a modified form of the Ångström turbidity equation. In addition, the distribution of particles sizes was found to follow the IEST-STD-CC 1246E cleanliness standard. The fractional coverage of the glass surface by particles could be determined directly or indirectly and, as expected, has a linear correlation with the transmittance. It thus becomes feasible to estimate the optical consequences of the soiling of pV modules from the particle size distribution and the cleanliness value. Soiling has a negative impact on the economic revenues of PV installations, not only because it reduces the amount of energy converted by the PV modules, but also because it introduces additional operating and maintenance costs and, at the same time, increases the uncertainty on the estimation of PV performance, leading to both higher financial risks and interest rates charged to plant developers. Power reductions greater than 50% have been reported in the literature because of soiling 1,2 ; it has been estimated that an average loss of 4% on the global annual energy yield of PV could cause losses in revenue on the order of 2 × 10 9 US$ annually 3. A careful monitoring of soiling is required to mitigate its effect 4. Soiling losses are generally quantified by using soiling stations. These systems are made of at least two PV devices, one of which is regularly cleaned while the other is left to soil naturally. By comparing the ratio of the electrical outputs of the two devices, it is possible to estimate the impact of soiling on the PV performance 5,6. The International Electrotechnical Commission's (IEC) metric to monitor and quantify the impact of soiling on PV modules is the soiling ratio, r s , which expresses the ratio of the electrical output of a soiled PV device to the output of the same device under clean conditions 7. Like the transmittance, a higher soiling ratio translates to less soiling deposited on the modules. A value of 1 indicates clean conditions, with no soiling. For a more detailed definition of r s , please refer to the Methodology section. The fractional loss of solar-generated power due to soiling is 1 − r s .

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A reflective 3D crossed compound parabolic‐based photovoltaic module (3D CCPC PV) was designed and its electrical and optical performance was analyzed for building integrated photovoltaic applications. A maximum power concentration of 3.0× was achieved compared to similar type of non‐concentrating module. The reduction of the concentration factor from the geometrical concentration of 3.61× for the designed 3D CCPC were due to manufacturing errors, mismatch losses, series resistance losses, and thermal loses. The experimental output was validated by developing a MATLAB simulation code for its electrical performance. Good agreements were observed between experimental and electrical simulation with maximum electrical conversion efficiency of the concentrating system of 14%. The experimental characterization of the optical efficiency was found to show a deviation of 19.4% from the 3D ray tracing simulation efficiency of 94.6% for direct incidence. This deviation is mainly due to the fact that 3D ray tracing simulation does not take the non‐uniform illumination distribution into account. Copyright © 2012 John Wiley & Sons, Ltd.

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Semi-transparent photovoltaic (PV) technology is attractive for building-integrated photovoltaics (BIPV) due to its ability to lower the admitted solar heat gain, to control the penetrating daylight and to generate onsite benevolent direct current power. In this work, semi-transparent cadmium telluride (CdTe) based BIPV as window was experimentally characterized using outdoor test cell in temperate UK climate. Spectral measurement confirmed its 25% visible transmission and 12% solar transmission. Thermal transmission and solar heat gain coefficient were calculated from measured thermal data. Overall heat transfer coefficient (U-value) of 2.7 W/m 2 K was found for outdoor and indoor characterization of CdTe BIPV window. A comparison with single glazed window has been produced emphasis its feasibility for Facade buildings.