Dye-Sensitized Solar Cells"
Stanford University PhD Dissertation Defense
Ying Chen (mihuhou@stanford.edu)
Research Advisor: Yoshio Nishi
Department of Electrical Engineering
Time: Monday, February 8th, @ 10:00 am
(refreshments served at 9:45 am)
Location: CISX Auditorium
ABSTRACT
Dye-sensitized Solar Cells (DSCs) have become a popular research topic
because of their low-cost, high-efficiency solar energy conversion. While
nanoparticle cell is currently the most efficient and stable DSC, nanowire
cells have shown some significant advantage that would make them superior to
nanoparticle cells. One such advantage is the fast and direct electron
transport, which was reported to be several hundred times faster than
trap-limited diffusion in nanoparticle cells, which can lower device
efficiency caused by electron-hole recombination. The efficiency of current
nanowire cells is primarily limited by the insufficiency of their internal
surface area due to the mechanical weakness of nanowire structures.
One solution to strengthen the nanowire structure is to build a framework
where individual nanowires are connected and prevented from clustering, so
as to increase the internal surface area and the efficiency of the solar
cell. Nanoframes containing 20nm diameter TiO2 nanowire arrays were
synthesized with polymer templates via cathodic Sol-Gel deposition followed
by 450oC sintering. Dye-sensitized Solar Cells based on this nanoframe were
fabricated and the effects of the top cover in the nanoframe, which is the
only difference between nanoframe cells and nanowire cells, were
investigated. The results show that the top cover does not prevent the I-
and I3- ions underneath from diffusing freely in the electrolyte and causes
no deterioration of the cell performance. The nanoframe cell is a promising
device in which nanowire arrays are strengthened and the effective internal
surface area have the potentiality to be increased without sacrificing the
advantages of nanowire cell compared to nanoparticle cell.
No comments:
Post a Comment