The photocurrent decreases linearly with increasing cell potential applied to the load V (figure 3 a). We extract the open-circuit voltage VOC by extrapolating the I-V characteristic to I = 0 and the short-circuit current ISC
FIGURE 2: Layout of DSSCs and equivalent circuits. Both basic DSSCs (a) and tested optimization strategies are (b-d) are depicted. The circuit diagram is modeled after . The alternative construction techniques lead to changes in the cell’s electrical model, which are highlighted.
by extrapolating to V = 0 (table 1). Both ISC and VOC of the enriched mixture cells increase with decreasing CNT coverage of the semiconducting active electrode. Similarly, the high-density cell of the regular mixture of nanotubes has a lower ISC and VOC than the low-density cell. The power transfer curves (figure 3b) show a peak power transfer of Pmax that occurs when the impedance of the load reaches R. The low-density enriched as well as the low-density regular cells deliver more power to the load than their high-density counterparts. This is consistent with both ISC and VOC being larger.
TABLE 1: Parameters of CNSCs.