Efficient quantum dot-sensitized solar cell with polystyrene-modified TiO_2 photoanode and with guanidine thiocyanate in its polysulfide electrolyte

摘要

Monodispersed polystyrene (PS, ca. 300 nm) latex particles are incorporated into a TiO_2 film. A polystyrene-modified TiO_2 film (M-TiO_2) with micro-cluster structure, containing microano-composite pores is thus obtained after sintering. Cadmium sulfide (CdS) quantum dots (CdS-QDs) are accumulated over M-TiO_2 and bare TiO_2 films (B-TiO_2) by successive ionic layer adsorption and reaction (S1LAR); we designate these films as M-TiO_2/CdS and B-TiO_2/CdS, respectively. Influence of SILAR cycles used for depositing CdS on B-TiO_2 and M-TiO_2 films on the performance of the pertinent quantum dot-sensitized solar cells (QDSSCs) is studied. The QPSSC with 6 SILAR cycles of M-TiO_2/CdS (M-TiO_2/CdS6) exhibited a solar-to-electricity conversion efficiency (n of one sun. Moreover, guanidine thiocyanate (GuSCN) is found to be a promising additive to the polysulfide electrolyte. The additive renders higher conversion efficiency (2.01%) to its QPSSC. Durability of the CdS-QDSSC is also tested. Scanning electron microscopy (SEM) is used to obtain the images of TiO_2 films and energy-dispersive X-ray spectroscopy (EDX) is employed to study the stoichiometric ratios of M-TiO_2/CdS and B-TiO_2/CdS. Incident photon-to-current conversion efficiencies (IPCE) of the QDSSCs are obtained to confirm thejsc behaviors of the cells.