All-solid-state quantum-dot-sensitized solar cells with compact PbS quantum-dot thin films and TiO2 nanorod arrays

To improve the electron injection efficiency from PbS quantum dots to TiO2 nanorods and prevent the direct contact of spiro-OMeTAD and TiO2 nanorods, a compact PbS quantum-dot thin film can be successfully obtained on TiO2 nanorod arrays 360 nm in length by repeated spin coating of Pb(Ac)2, Na2S and 1,2-ethanedithiol solution in a step-by-step process. The corresponding solid-state quantum-dot-sensitized solar cells are fabricated using a novel structured FTO/compact PbS quantum-dot thin film sensitized TiO2 nanorod array/spiro-OMeTAD/Au that achieves a photoelectric conversion efficiency of 3.57% under AM 1.5 G illumination (100 mW cm−2), which represents a high value among all-solid-state PbS quantum-dot-sensitized TiO2 nanorod array solar cells.