Densely packed siloxane barrier for blocking electron recombination in dye-sensitized solar cells

Solar Cell Enhancement from Supercritical CO2 Dye Surface Modification of Mesoporous TiO2 Photoanodes

In recent years, in an effort to reach Net Zero Emissions, there has been growing interest by various academic and industry communities to develop chemicals and industrial processes that are circular, sustainable and green. We report the rapid, simple and effective surface modification of a porous metal oxide with organic dyes using supercritical carbon dioxide (scCO2). Titanium dioxide (TiO2) photoanodes were coated in very short times, under mild conditions and the excess dye recovered afterwards for reuse. The process obviates the need for conventional toxic solvents, the generation of unwanted waste streams, and more importantly, we see an unexpected device performance enhancement of 212 and 163 % for TerCOOTMS, 2 a and TerCN/COOTBDMS, 4 dyes, respectively, when compared to the conventional solvent deposition method.

Improvements in photoelectric performance of dye-sensitised solar cells using ionic liquid-modified TiO2 electrodes

One of the major problems in dye-sensitised solar cells (DSSCs) is the aggregation of dyes on TiO₂ electrodes, which leads to undesirable electron transfer. Various anti-aggregation agents, such as deoxycholic acid, have been proposed and applied to prevent dye aggregation on the electrodes. In this study, we designed and synthesised a phosphonium-type ionic liquid that can be modified on the TiO₂ electrode surface and used as a new anti-aggregation agent. Although the modification of the ionic liquid onto the electrode reduced the amount of dye adsorbed on the electrode, it showed a significant anti-aggregation effect, thereby improving the photovoltaic performance of DSSCs with N3 and J13 dyes. This finding suggests that ionic liquids are effective as anti-aggregation agents for DSSCs.

The modification of the phosphonium-type ionic liquid onto the TiO₂ electrode reduced the amount of dye adsorbed on the electrode and showed significant aggregation effect, thereby improving the photovoltaic performance of DSSCs.

An insight into the hybrid dye-sensitized solar cell from polyaniline-CdS nanotubes through impedance spectroscopy

Composites of polyaniline (PANI) and cadmium sulfide nanoparticles (CdS NPs) are in situ synthesized by polymerizing aniline in acetic acid medium for different concentrations of CdS NPs. The composites, characterized by scanning and transmission electron microscopy, exhibit nanotubular morphology of PANI decorated with nanospheres of CdS NPs at their outer surface. The FTIR and UV-vis spectra indicate strong interaction between PANI and the CdS NPs suggesting a good conjugate for photovoltaic applications. The dc conductivities of the composite increase with an increase of the CdS concentration showing a maximum of 1.17 × 10^-2 S cm^-1 for the C200 sample (obtained by polymerizing 182 μL aniline with 200 mg CdS). The current-voltage plots indicate that the photocurrent is higher from the dark current and the separation between the dark current and photocurrent is maximum in C200. The effectiveness of these composites in DSSCs is studied under illumination of 100 mW cm^-2 and the C200 device exhibits a maximum open circuit voltage of 0.73 V, a short circuit current of 8.22 mA cm^-2, and a power conversion efficiency of 3.96%. The impedance study of the cells indicates that the lifetime of the photo-injected electrons is highest (1.34 ms) for the C200 sample, explaining the maximum PCE among the composites.

TiO2 surface engineering with multifunctional oligomeric polystyrene coadsorbent for dye-sensitized solar cells

Oligomeric, hydrophobic coadsorbents based on polystyrene (M_n = 2400) terminated by a carboxylic acid exhibit dual functions in dye-sensitized solar cells: passivation of the TiO₂ surface, and promotion of the strongly-anchored N719 dyes.