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A modular array of light emitting diodes of six different wavelengths is modelled and experimentally tested to provide Class AAA solar simulator illumination over an area of 20 cm2. The module demonstrates uniform distribution of light flux density across the sample test plane region, achieving Class A AM 1.5 G irradiance (100 mW/cm2) across the 400 to 1100‐nm wavelength range. The new system has a spectral match of 99.5%, a spatial non‐uniformity of 2.0%, and a temporal instability of <0.2%. The performance of the design (which will allow for large area simulators to be cheaply assembled from multiple modules) is then critically assessed in terms of the existing solar simulator standards and benchmarked against a conventional simulator. This paper presents the design, development, and characterisation of a light emitting diode solar simulator module that can be tessellated to form large area solar simulator systems. It is demonstrated that the system has Class AAA performance and that by combining low‐cost components and a tessellating modular design, it is possible to upscale the design to any desired illumination area. [ABSTRACT FROM AUTHOR]

Direct metallization of lightly doped n-type crystalline silicon (c-Si) is known to routinely produce non-Ohmic (rectifying) contact behaviour. This has inhibited the development of n-type c-Si solar cells with partial rear contacts, an increasingly popular cell design for high performance p-type c-Si solar cells. In this contribution we demonstrate that low resistance Ohmic contact to n-type c-Si wafers can be achieved by incorporating a thin layer of the low work function metal calcium (ϕ ~2.9 eV) between the silicon surface and an overlying aluminium capping layer. Using this approach, contact resistivities of ρc ~ 2 mΩcm2 can be realised on undiffused n-type silicon, thus enabling partial rear contacts cell designs on n-type silicon without the need for a phosphorus diffusion. Integrating the Ca/Al stack into a partial rear contact solar cell architecture fabricated on a lightly doped ( ND = 4.5 × 1014 cm−3) n-type wafer resulted in a device efficiency of η = 17.6% where the Ca/Al contact comprised only ~1.26% of the rear surface. We demonstrate an improvement in this cell structure to an efficiency of η = 20.3% by simply increasing the wafer doping by an order of magnitude to ND = 5.4 × 1015 cm−3. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The cover image is based on the Applications Modular LED arrays for large area solar simulation by Alaa Y. Al‐Ahmad et al., DOI: 10.1002/pip.3072 Image Credit: Centre for Organic Electronics, Department of Physics, University of Newcastle. [ABSTRACT FROM AUTHOR]

Abstract: Mixed matrix membranes based on zeolite LTL dispersed in a glassy polyimide, 6FDA–6FpDA, as well as in block copolymers composed of 6FDA–6FpDA and amine-terminated polydimethylsiloxane (PDMS) were fabricated and characterized for gas transport properties. Pure gas permeability tests were performed using He, O2, N2, CH4 and CO2 for each membrane. Permeability was shown to increase for all gases as the siloxane content in the copolymer increased. The addition of zeolite L to the polymer matrix lowered the permeability of all gases regardless of the polymer matrix, and did not offer improvements in the ideal selectivity of any gas pair investigated. [Copyright &y& Elsevier]

Abstract: Mixed matrix membranes composed of zeolite L dispersed in a 6FDA-6FpDA-DABA polyimide matrix were fabricated and characterized for gas separation performance. The interfacial contact between the two phases relied on introducing amine functional groups on the zeolite surface and covalently linking them with carboxylic acid groups present along the polyimide backbone. While certain gas permeabilities in the membranes increased with the addition of zeolite L, overall these mixed matrix membranes did not offer substantial selectivity improvements. Separate gravimetric sorption measurements indicated that the sorption capacity of zeolites modified with silane coupling agents is substantially lower than the gas sorption in unmodified zeolites. [Copyright &y& Elsevier]

Currently, large-scale roll-to-roll production of printed organic photovoltaics (OPVs) involves high temperature annealing steps that are not compatible with thermally sensitive substrates, such as coated fabrics. In particular, the processing temperatures needed to produce the required crystalline ordering in the printed films are typically above the deformation and melting-points of these substrates. In this paper we investigate the use of local solvent recrystallisation (solvent annealing) on the roll-to-roll scale as a method for avoiding high-temperature thermal annealing. Solvent annealing was performed by slot-die coating a mixture of chloroform and methanol over a previously printed P3HT IC X A active layer film. Peak device performance was found for the 30% chloroform/70% methanol annealing case which increased device performance by a factor of 4 over the not treated devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)