Titanium dioxide quantum dots: Magic materials for high performance underlayers inserted into dye-sensitized solar cells

摘要

Well crystalline TiO_2 quantum dots with size about 3.6 nm are synthesized and used to fabricate high performance underlayers in dye-sensitized solar cells (DSCs). The TiO_2 quantum dots underlayer (TiO_2-QD-UL) covered FTO glasses show excellent transmittance as that of the non-covered one. The TiO_2-QD-UL can efficiently suppress dark reaction in the cell by increasing the onset bias voltage for generating dark current to a higher value and shifting flat-band potential of the photoanodes to a more negative position. Moreover, the shorten electron transport time, lengthen electron life time, enhanced charge collection efficiency, and the decreased electron transport resistance between TiO_2/FTO glass are obtained with TiO_2-QD-UL in the cell. Power conversion efficiency of the DSC with TiO_2-QD-UL in the photoanode is enhanced from 7.10% to 9.43%, corresponding to 32.82% increment.