Stepped light-induced transient measurements of photocurrent and voltage in dye-sensitized solar cells based on ZnO and ZnO:Ga

Abstract

In order to explain the higher short-circuit current ͑J sc ͒ with comparable open-circuit voltage ͑V oc ͒ from dye-sensitized solar cells ͑DSCs͒ based on gallium-modified ZnO ͑ZnO:Ga͒ porous electrodes, the diffusion coefficient ͑D͒ and electron lifetime ͑͒ in DSCs with and without Ga-modified ZnO were studied by stepped light-induced transient measurements of photocurrent and voltage. In comparison to DSCs based on ZnO electrodes, the ZnO:Ga-based solar cells provided lower D and higher values. The results were interpreted according to the transport-limited recombination model, where the Ga modification induced a higher density of intraband charge traps. At matched electron densities, a decrease in V oc from DSCs based on ZnO:Ga was observed, suggesting a positive shift of the ZnO:Ga conduction band edge. The higher J sc can be explained by the positive shift of the ZnO:Ga conduction band edge in addition to the increased roughness factor of the electrode due to the Ga modification.

The Effect of the Dielectric Environment on Electron Transfer Reactions at the Interfaces of Molecular Sensitized Semiconductors in Electrolytes

“…The effect is present also for the case of tetrabutylammonium-based salts but only when low dye loading samples are considered. Because no major dependence on the type of ion is normally observed for the ambipolar diffusion coefficient of cells with large electrolyte concentrations, − this result suggests that access of the cation to the oxide surface is key to the increased recombination rate. Addition of tBP to an electrolyte containing LiP still induces a decrease in recombination rate as discussed above.…”

A novel high-performance photovoltaic–thermoelectric hybrid device

“…Dye-sensitized solar cells (DSSCs) have received much attention since they were first reported in 1991. [1][2][3][4][5][6][7][8][9] DSSCs are promising alternatives to conventional silicon-based photovoltaic devices due to their low production cost and high efficiency for energy conversion. Generally, DSSCs consist of three main components: a dye-adsorbed porous nanocrystalline TiO 2 film on a transparent conductive oxide (TCO)-coated glass substrate, an iodide/ triiodide redox couple electrolyte, and a platinized TCO-coated glass substrate as a counter electrode.…”

Solvent-Dependent Functional Aggregates of Unsymmetrical Squaraine Dyes on TiO2 Surface for Dye-Sensitized Solar Cells

“…Stepped light-induced transient measurement of photocurrent and photovoltage (SLIM-PCV)/charge extraction measurement is a fast and simple tool for scrutinizing the charge recombination reaction at the dye–TiO 2 /electrolyte interface and correlating the solar cell performance. − Here, to study the relationship between the backward electron transfer reactions and the type of dye aggregates on the TiO 2 surface formed in good and bad solvents, the injected electrons’ diffusion coefficient ( D n ) at short-circuit conditions, electron lifetime (τ n ) at open-circuit conditions, and electron density on the TiO 2 surface were measured (Figure and Figures S7 and S8). In addition to the sensitizing solvents, there are three conditions in which the interfacial electron transfer was studied: (i) I – /I 3 – electrolyte without 4- tert -butylpyridine (TBP), (ii) I – /I 3 – electrolyte with TBP as an additive, and (iii) I – /I 3 – electrolyte with TBP as an additive and CDCA as a co-adsorbent in the dye dipping solution .…”