Combination of short-length TiO2 nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

Abstract

Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO2 nanorod array with the length of 600nm, the diameter of 20nm, and the areal density of 500μm−2 is successfully prepared by the hydrothermal method using the aqueous grown solution of 38mM titanium isopropoxide and 6M hydrochloric acid at 170°C for 105min. The compact PbS quantum-dot thin film on the TiO2 nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO2 nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO2 nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion efficiency of 4.10%, along with an open-circuit voltage of 0.52V, a short-circuit photocurrent density of 13.56 mAcm−2 and a fill factor of 0.58.