Comparing incorporation of carbon nanotubes in hierarchical porous photoanodes of quantum dot and dye sensitized solar cells

The carbon nanotubes (CNT)s are incorporated in hierarchical porous photoanodes of dye sensitized solar cell (DSSC) and quantum dot sensitized solar cell (QDSC). The short circuit current density (JSC) is increased in both cases with addition of CNTs. However, the improvement in JSC of QDSC is more noticeable compared to that of DSSC, which causes dramatic enhancement in efficiency (40%) of this device with incorporation of CNTs. CNTs can presumably promote the charge injection process by lowering the exciton diffusion path through quantum dots (QD) in QDSC. Moreover, CNTs entirely increase the electron lifetime in QDSC by decreasing the effect of surface trap states in the TiO2/QD interface and encouraging the injection of electrons towards CNT channels before back recombination.