The Design And Fabrication Of3-D Microstructure Substrate And The Application In Dye Sensitized Solar Cells

Due to the convenience of fabrication processes and the low cost, Dye Sensitized Solar Cells (DSSC) are regarded as one of the most promising solar cells. However, there exist a drawback in the light absorption and the carrier collection which makes the conversion efficiency lower than the theoretical efficiency. In the paper, we introduced a new-type design proposal of the cell substrate to improve the light absorption and electron collection. The main work is as below:1. Designed a new-type silica A-shape wedge arrays to enhance the incident light trapping.Based on the fabrication of silica needle arrays through a TAFE wet etching method, new-type silica A-shape wedge arrays (SWAs) were fabricated by a combined process of template fabrication, hot embossing and sol-gel replication. Using this procedure, high quality silica A-shape wedge arrays can be obtained with designed sizes and shapes over a large area. The taper height and interspace of SWAs can be tuned by the imprint depth during the hot-embossing process. This technology provides a cost-effective method to fabricate A-shape silica wedges. The A-shape wedge arrays can reflect the light for many times, which may lead an increase in the light trapping. By changing the primal template, other patterned silica substrate can also be fabricated, such as grating, pillar and spherical structures. These silica based microstructure can find many applications in semiconductor devices, solar cells and optics etc.2. Enhanced electron collection via pattered silica substrate.The effects of patterned substrate on carrier collection in DSSCs were investigated experimentally. Through a combined process of sputtering, photo-lithography and wet etching, we fabricated a new-type patterned silica substrate of which the period and height could be adjusted easily. The period was matched with the electron diffusion length and the height was adjusted with the thickness of DSSC. After the patterned substrate was introduced into the DSSC, the carrier concentration gradient was change from the2-D to the3-D state which could promote the collection of elections. The quantum efficiency and short-circuit current density were higher than the flat film cells. The introducing of patterned substrate didn’t collide with the other method in the DSSC field. Hence, the research in the paper provided a way to enhance the property of DSSC without any other materials.