Introduction of polysulfide anions to increase the loading quantity of PbS quantum-dots for efficient solid-state quantum-dot sensitized TiO 2 nanorod array solar cells

Abstract

To increase the loading quantity of PbS quantum-dots, the polysulfide anion (S₂²⁻) was firstly introduced in successive ionic layer absorption and reaction process to prepare PbS quantum-dot thin films on TiO₂ nanorod arrays. The influence of polysulfide anion (S₂²⁻) concentrations in the precursor solution on the deposition of PbS quantum-dot thin films was systematically investigated and the photovoltaic performance of the corresponding solid-state PbS quantum-dot sensitized solar cells with spiro-OMeTAD was evaluated. The loading quantity and crystallinity of PbS quantum-dots increased with the increase of polysulfide anion (S₂²⁻) concentrations from 0 to 1 mM and 2 mM. When the polysulfide anion (S₂²⁻) concentration was 1 mM and the surface of TiO₂ nanorod arrays was modified by 3-mercaptopropionic acid, the optimal photoelectric conversion efficiency of 4.75% was achieved, along with the open-circuit voltage of 0.56 V, short-circuit photocurrent density of 13.00 mA cm⁻² and fill factor of 64.8%. The photoelectric conversion efficiency of 4.75% was relatively high in solid-state PbS quantum-dot sensitized solar cells using successive ionic layer absorption and reactions.

Graphical abstract

To increase the loading quantity of PbS quantum-dots, the polysulfide anion (S₂²⁻) was firstly introduced in successive ionic layer absorption and reaction process to prepare PbS quantum-dot thin films on TiO₂ nanorod arrays. The optimal photoelectric conversion efficiency of 4.75% was achieved, along with the open-circuit voltage of 0.56 V, short-circuit photocurrent density of 13.00 mA cm⁻² and fill factor of 64.8%.

http://bit.ly/2TehZ5X