Dye-sensitized solar cells (DSSCs) were prepared using various food dyes. Food dyes are economically superior to organometallic dyes since they are nontoxic and inexpensive. The spectrophotometric evaluation of chosen food dyes in solution and on a TiO₂ substrate show that the dyes form J-aggregation on the photoelectrode substrate. Oxidation of potential measurements for used food dyes ensured an energetically permissible and thermodynamically favorable charge transfer throughout the continuous cycle of a photo-electric conversion. The performance of dye-sensitized solar cells based on food dyes was studied. The results illustrate that the dye containing carboxylic acid and sulfonic acid as the acceptor group gave the maximum conversion efficiency 4.20%.

Clean and cheap device, namely dye-sensitized solar cells (DSSCs) were fabricated using a natural dye extracted from Sambucus ebulus. We prepared five sample solutions with various pH in the extraction process to improve power conversion efficiency. The UV–visible absorption investigation of sample solutions and on photoanode show the dyes from J-type aggregation on a photoanode substrate. Redox properties of all sample solutions certify thermodynamically a charge transfer from excited state to conduction band TiO₂. The optical properties of various dye solutions were investigated and results showed darkness and bluish tint effect of dye solutions extracted in basic environment rather than those extracted in acidic condition. Moreover, in comparison to the basic condition, the dye solutions extracted in acidic environment were more saturated and colorimetrically less different from that one which extracted in neutral condition. Photophysical and photoelectrochemical performance of natural extraction dyes have been studied in dye-sensitized solar cell devices. The results show the rather high conversion efficiency of 0.57%, 1.15%, 1.02%, 0.35% and 0.15% of each individual dye extraction, respectively.

Dye sensitized solar cells (DSSCs) based on indigo dyes exhibit suitable conversion efficiency. These organic dyes have been undergone for aggregation. Electron transfer process is reduced due to an aggregation of molecular dyes. Therefore, anti-aggregation agent is commonly utilized in fabrication of DSSCs. In the present study, two anti-aggregation agents namely as 3α,7α-dihydroxy-5β-cholanic acid (cheno) and 3α,7α,12α-trihydroxy-5β-cholanic acid (cholic acid) were added to indigo dye solution in DSSCs in order to determine the photovoltaic parameters such as short circuit photocurrent, open circuit voltage and conversion efficiency of each individual dye in the absence and presence of anti-aggregation agents. The results show that the conversion efficiencies are improved with reduced aggregation. Spectrophotometric evaluations of the indigo dyes in solution and on a TiO₂ substrate were carried out in the absence and presence of anti-aggregation agents in order to estimate changes in the status of the dyes in different environments. J-type aggregates on the nano TiO₂ are reduced in the presence of anti-aggregation agents.

Four dye-sensitized solar cell devices are designed and fabricated based on natural dyes extracted from Celosia Cristata, Saffron, Cynoglossum, and eggplant peel, as photosensitizers. The UV–vis technique has been served to determine maximum absorption of natural extract and pre-dyed photoanode. The Fourier transform infrared (FT-IR) was employed to cover the presence of functional groups. The cyclic voltammetry method has been employed to assess the possibility of charge transfer from dried natural dyes to the photoelectrode. The performance of natural-based dye-sensitized solar cells is determined subsequently. The highest power conversion efficiency was ca. 1.38%, which belonged to Celosia Cristata extract. The devices were examined for higher efficiencies, individually, co-sensitized arrangement and/or in tandem with each other.

A novel methodology was implemented in the present study to concurrently control power conversion efficiency (η) and durability (D) of co-sensitized dye solar cells. Applying response surface methodology (RSM) and Desirability Function (DF), the main influential assembling (dye volume ratio and anti-aggregation agent concentration) and operational (performance temperature) parameters were systematically changed to probe their main and interactive effects on the η and D responses. Individual optimization based on RSM elucidated that D can be solely controlled by changing the ratio of vat-based organic photosensitizers, whereas η takes both effects of dye volume ratio and anti-aggregation concentration into account. Among the studied factors, the performance temperature played the most vital role in η and D regulation. In particular, however, multi-objective optimization by DF explored the degree to which one should be careful about manipulation of assembling and operational parameters in the way maximization of performance of a co-sensitized dye solar cell.

Different anchoring groups such as thiophene-2-acetic and malonic acid were investigated for synthesis of new photosensitizers. The new dyes (photosensitizers) were made pure and determined by various analytical techniques. The chemical structure of synthesized materials was certified by analytical studies. UV-Visible and fluorescence spectra revealed intense fluorescence and absorption for organic photosensitizers. The cyclic voltammetry results showed that the two photosensitizers were suitable for dye sensitized solar cell preparation. The work electrode was gathered using tin (IV) oxide nanoparticles in dye-sensitized solar cells structure. The new photosensitizers and tin (IV) oxide were used for photovoltaic devices preparation. The power conversion efficiency was obtained as about 4.12 and 4.29% for Dye 1 and Dye 2, respectively.