Study of band bending effect in Dye Sensitized Solar Cell through Constant-Current-Discharging Voltage Decay

TL;DR

This paper introduces a measurement method to analyze band bending in dye-sensitized solar cells using voltage decay, proposing a theoretical model that aligns with experimental data to explain the underlying electron transport mechanisms.

Contribution

It develops a novel measurement technique and a theoretical model to understand band bending effects in dye-sensitized solar cells.

Findings

The measurement method effectively characterizes band bending.

The theoretical model explains the origin of band bending.

Experimental results agree with the model predictions.

Abstract

A measurement method of constant-current-discharging voltage decay is established to characterize the band bending effect in the heterojunction of conducting glass/TiO2 for typical dye-sensitized solar cells. Furthermore, a dark-state electron transport regarding the TiO2 conduction band bending is proposed based upon the viewpoints of thermionic emission mechanism, which suggests an origin of the band bending effect in a theoretical model. This model quantitatively agrees well with our experimental results and indicates that both the Fermi level decay in TiO2 and the potential difference across the heterojunction will lead to the TiO2 conduction band bending downwards.