Assembly of Cu–In–Sn–Se quantum dot–sensitized TiO2 films for efficient quantum dot–sensitized solar cell application

Abstract

Ternary I-III-VI (such as CuInSe2 and AgInS2) quantum dots (QDs) have been increasingly studied in the field of photoelectric conversion applications. Here, we prepare a relatively less toxic Cu–In–Sn–Se (CISSe) QD by an organic high-temperature hot injection method, and this material is subsequently applied as a functional sensitizer to produce QD-sensitized solar cells (QDSSCs). Because of the effect of Sn doping and ZnS passivation, the TiO2/CISSe/ZnS photoanode obtains the greatest composite resistance (985.5 Ω·cm2) and highest electron lifetime (120.23 ms) among the experimentally compared materials, showing the further inhibition of charge recombination when compared with bare Cu–In–Se solar cells while effectively enhancing the collection efficiency of photogenerated electrons. Using CISSe/ZnS QDs as a sensitizer, the power conversion efficiency of the QDSSC reaches 6.7%, of which Voc, Jsc, and FF reach 0.559 V, 22.93 mA/cm2, and 0.52, respectively. It provides a new possibility for the development of QDSSCs.