C-L Lee, W-H Lee, C-H Yang, H-H Yang
Changes in dye-sensitized solar cell performance related to active area size were investigated. The cell geometry was defined by introduction of a sub-electrode, which was uniform up to 4 cm2, and showed little change in performance up to a cell area of 1 cm2. When the cell area increased above 1 cm2, the power conversion efficiency of cell dropped significantly, because that fill factor ( FF ) drop and short circuit current density (Jsc ) suppression. The changes in FF and Jsc could not be described solely by a Shockley diode equation based on an equivalent circuit model unless photocurrent collection was also considered. As cell area increased, collection efficiency deviated from unity, which further reduced device performance. That deviation is attributed to acceleration of recombination loss at low built-in junction potentials.