In this paper we have demonstrated the simple, low cost, low temperature, hydrothermal growth of weeping willow ZnO nano-trees with very long branches to realize high efficiency dye-sensitized solar cells (DSSCs). We also discuss the effects of branching on solar cell efficiency. By introducing branched growth on the backbone ZnO nanowires (NWs), the short circuit current density and the overall light conversion efficiency of the branched ZnO NW DSSCs increased to almost four times that for vertically grown ZnO NWs. The efficiency increase is attributed to the increase in surface area for higher dye loading and light harvesting and also to reduced charge recombination through direct conduction along the crystalline ZnO branches. As the length of the branches increased, the branches became flaccid and the increase in solar cell efficiency slowed down because the effective surface area increase was hindered by branch bundling during the drying process and subsequent decrease in the dye loading.

The effect of various materials of the spherical scattering centre in a TiO₂ nanoporous structure in dye-sensitized solar cells (DSSCs) was investigated by both theoretical simulation and experiment. Three materials, titania, electrolyte and silica, were investigated using the Mie Theory, in which the concepts of volume total cross section and solar spectrum were accommodated for better accuracy. Of those materials, silica was chosen in this study due to its perfectly transparent nature, easy size controllability and perfectly spherical shape, which make silica most suitable for understanding the scattering effect with a simple optical approach. The validity was proved by experiment with various sizes of silica beads (0.3, 0.6, 0.9, 1.2, 1.5 µm) embedded in DSSCs; experiments revealed the same trend as did the simulation. The overall efficiency of the DSSCs was increased by 20.4% using 300 nm diameter silica beads. The efficiency versus bead size had a peak with beads of 300 nm diameter and decreased as the bead size increased. This study showed that silica could be a good candidate for scattering particles in DSSCs. Furthermore, this study could be considered a valuable reference for further investigations of scattering phenomena by small spherical particles or arbitrary shape of particles in DSSCs.

Signage systems are the main means of resolving the wayfinding problem in an emergency evacuation. However, recent literature has proven that signage systems are often not effective in an indoor wayfinding decision-making situation. Many studies that attempted to solve the problem did not consider the interaction between the optimal location of signage systems and gaze characteristics. Therefore, this study aimed to provide basic database to determine the optimal location of signage by analysing the characteristics of eye movements according to the type of junction. To achieve this, we conducted evacuation experiments in a maze set composed of eight junctions that we created ourselves and analysed the eye movement data of participants with 5196 gaze points and duration of 895,581.49 ms. The result showed that participants most often look between 100 cm and 150 cm (vertical height) in the corridor and in junctions. In addition, the gaze points of the evacuees are quantified by the horizontal and vertical directions according to the type of junction where the wayfinding decisions occur. This investigation showed that there are marked differences depending on the type.