An optimized series interconnection process can provide many benefits for the manufacture of thin-film PV including lower panel transit times, lower capital equipment costs, smaller line foot print ...and less panel area wasted. The One Step Interconnect (OSI) process has been previously introduced 1. It utilizes conventional laser scribing and inkjet additive manufacture to form the series interconnect. Good electrical performance has previously been achieved on CdTe mini-modules. Here the latest developments are presented. Further mini-module electrical results are shown with Fill Factors (FFs) of, on average, 70% and up to 80%. No loss of fill factor is seen as cells are connected in series. An extensive lifetime testing program is now underway. An encapsulation process has been found and verified using the IEC 61646 standard damp heat test for packaging integrity. Over 400 hours of thermal cycling has been completed on OSI interconnected modules with no degradation in power output.
We report the successful growth of CdTe/CdS core-shell structures on a glass substrate using a metamorphic growth approach. The CdTe wires were grown by close space sublimation using the ...vapor-liquid-solid technique. The CdS shell was grown by chemical bath deposition. Detailed characterization has been undertaken using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis and low-temperature photoluminescence spectroscopy. This has confirmed the successful growth of these structures. The luminescence properties of core-shell structures show features more commonly observed in single crystals rather than polycrystalline material. These structures show considerable promise for photovoltaic device applications.
Mainly due to its much larger exciton Bohr radius, Ge, in the form of nanocrystals, is expected show more pronounced quantum confinement effects compared to Si nanocrystals. SiGe alloys also ...constitute a more attractive material than Si in terms of both industrial applications and fundamental research: the lifetime of the 'porous Si-like' PL of porous SiGe is observed to be approximately two orders of magnitude faster than that of porous Si. Moreover, the bandgap of Si-Ge alloys can be intentionally varied between those of pure Si and Ge via the alloy composition. In this study, an investigation has been made of the microstructural properties of visible PL Group IV nanostructures (SiGe and Ge) that have been rather much less studied in the literature, for example, in comparison to Si nanocrystals. For the first time in the literature the confinement of phonons in SiGe nanocrystals has been shown, in anodised porous SiGe films, and variations in the film composition were estimated utilising Raman spectroscopy. Methods such as stain etching, ion-implantation, and spark processing, were employed to synthesise Ge nanostructures. Particle sizes were usually estimated by modelling the Raman spectra in line with a phonon confinement model. Properties of 2-10 nm Ge nanostructures, ranging in structure from partially amorphous to crystalline, and in various environments, e.g. oxide matrices, were studied. Typical PL spectra were observed in the visible from these samples. These spectra were determined to be originating either due to Ge nanocrystals or other chemical origins, such as defects in GeOxs or defects in host matrices (e.g. SiO2, GeOx). It is recommended that samples with a wider range of particle sizes must be prepared, preferably 'oxide-free', using the first two methods, and characterised optically from near UV to near IR in order to observe clearly the size dependence of the PL emission from Ge nanocrystals.
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