Three kinds of important properties of the solar cell were calculated: short-circuit current density, open-circuit voltage, and conversion efficiency. Two equations which show the relationship between the minority-carrier diffusion length and the grain size or the etch pit density were used for the calculation. The dependence of the properties on the cell thickness were estimated as a function of grain size and etch-pit density. The effect of the internal reflectance with varying minority-carrier diffusion length was also examined. The results show that thin film polycrystalline silicon solar cells have the potential to attain an efficiency of 17% even at a film thickness of 2 μm if the grain size is bigger than 10 μm and the etch-pit density of less than 1×106 cm−2. The principal requirement is to achieve efficient light trapping.

Cellulose paper has strong potential as an analytical platform owing to its unique characteristics. In the present study, we investigated a procedure for functionalizing the surface of cellulose paper by dip-coating a mixture of a functional polymer and a perfluoroalkylated surfactant (surfactant 1). The functional polymer comprised a mixture of methyl methacrylate and poly(ethylene glycol) methacrylate monomers. The monomer ratio in the functional polymer affected the hydrophilicity and water absorbance of the cellulose paper after dip-coating.Furthermore, the presence of surfactant 1 during dip-coating promoted the surface segregation of poly(ethylene glycol) (PEG) moieties in the polymer, which enhanced the hydrophilicity, prevented nonspecific protein adsorption, and maintained the water absorbance of the dip-coated cellulose paper. Dip-coating with another functional polymer containing biotin groups produced a cellulose paper with a biotin-decorated surface in a one-step procedure. The displayed biotin groups immobilized avidin on the surface, and the PEG moieties in the polymer prevented nonspecific protein adsorption. We then immobilized a thrombin-binding DNA aptamer on the avidinimmobilized cellulose paper to prepare a paper-based analytical device. It is possible to visualize thrombin in model solutions and serum using the paper-based analytical device.

We propose a novel approach to stably immobilize gold nanoparticles (AuNPs) on a plastic substrate and demonstrate that the modified substrate is also capable of immobilizing biomolecules.

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