The interfacial dipolar polarization in inverted structure polymer solar cells, which arises spontaneously from the absorption of ethanolamine end groups, such as amine and hydroxyl groups on ripple-structure zinc oxide (ZnO-R), lowers the contact barrier for electron transport and extraction and leads to enhanced electron mobility, suppression of bimolecular recombination, reduction of the contact resistance and series resistance, and remarkable enhancement of the power conversion efficiency.

Dry etching plasma parameters were optimized for texturing single crystalline thin silicon solar cells and hence for high efficiency. In reactive ion etching (RIE) texturing, a low etch depth (∼2 µm) was obtained compared with the etch depth that occurred in the wet chemical texturing process. For the flow ratios (SF6/O2) of 2 and 3, needle-like and cylindrical type structured surfaces were obtained. In the RIE process, the effects of working pressure, flow ratio, and etching time on reflectance and electrical properties of single crystalline silicon solar cells were investigated. The textured c-Si wafer with needle-like structure has good antireflectance behaviour. The interface defect density (Dit) in these textured silicon wafers increased with etching time. But an improvement in the reduction of interface trap density was observed through the annealing effect. Single crystalline solar cells with cylindrical type texture have higher values for open circuit voltage, short circuit current and efficiency in spite of a higher reflectance as compared with those needle-like structures. It is observed that the optimized SF6/O2 based chemistry in the RIE method is more suitable for thin crystalline silicon solar cells instead of the conventional wet texturization processes.

Changes in the electrical resistance of nitrogen incorporated Ge2Sb2Te5 (NGST) films were investigated as a function of nitrogen content by four-point probe and ac two-point probe methods. Some nitrogen is initially located inside the cubic structure, resulting in a significant increase in crystalline temperature and electrical resistance. As the amount of incorporated nitrogen increases, excess nitrogen accumulates in the grain boundaries, which does not contribute substantially to the increase in electrical resistance and the crystallization temperature. The supersaturated nitrogen distorts the Ge2Sb2Te5 structure, resulting in a NGST film with a structure that is different from the metastable fcc structure. X-ray absorption spectroscopy revealed that Ge–N and N2 molecular states were present in the film and gradually increased in proportion to the amount of incorporated nitrogen. Moreover, the nitrogen states were very stably maintained even during the phase transition process.

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In this article, we demonstrate the fabrication of colloidal crystals made of polystyrene oblate particles with face centered lattice structures. Monodisperse spherical polystyrene nanospheres were self-assembled into colloidal crystal followed by the infiltration of polydimethylsiloxane (PDMS) precursors into the self-assembled structure. After curing the infiltrated PDMS precursors, the composite colloidal crystals were deformed by compressive stress acting parallel or vertical to the [111] direction of the face centered cubic lattice of the colloidal crystals. After deformation, the shape of the constituent spherical polystyrene particles was changed into oblate ellipsoidal morphology. Depending on the direction of the compressive stress, the stop bands of deformed colloidal crystals were controlled and reflectance spectra were measured to observe the blue-shift or red-shift phenomena of the stop band after deformation. Shear stress was also applied to the composite colloidal crystal to change the morphologies of the constituent polystyrene particles into oblate spheroids, and the stop band position and the band gap width of the reflectance spectrum were modified.