Fabrication and characterization of dye-sensitized solar cells based on natural plants

Development of dye-sensitized solar cells using pigment extracts produced by Talaromyces atroroseus GH2

The identification of more efficient, clean, secure, and competitive energy supply is necessary to align with the needs of sustainable devices. For this reason, a study for developing innovative dye-sensitized solar cells (DSSCs) based on microbial pigments is reported starting from Talaromyces atroroseus GH2. The fungus was cultivated by fermentation and the extracellular pigment extract was characterized by HPLC-DAD-ESI-MS analyses. The most abundant compound among the 22 azaphilone-type pigments identified was represented by PP-O. The device's behavior was investigated in relation to electrolyte and pH for verifying the stability on time and the photovoltaic performance. Devices obtained were characterized by UV-vis measurements to verify the absorbance intensity and transmittance percentage. Moreover, photovoltaic parameters through photo-electrochemical measurements (I-V curves) and impedance characteristics by Electrochemical Impedance Spectroscopy (EIS) were determined. The best microbial device showed a short-circuit current density (Jsc) of 0.69 mA/cm2, an open-circuit photo-voltage (Voc) of 0.27 V and a Fill Factor (FF) of 0.60. Furthermore, the power conversion efficiency (PCE) of the device was 0.11%. Thus, the present study demonstrated the potential of microbial origin pigments for developing DSSCs.

Magnesium sulfate as a potential dye additive for chlorophyll-based organic sensitiser of the dye-sensitised solar cell (DSSC)

In this work, a new chlorophyll dye-sensitiser derived from mitragyna speciosa (MS) leaves, also known as Kratom, was employed for dye-sensitised solar cells (DSSCs). The influence of magnesium sulfate (MgSO₄), a low-cost dye additive, and suitable extraction solvents on the performance of DSSCs were examined. Here, the optical properties were investigated using UV-Visible spectroscopy and the functional anchoring group were investigated by FTIR spectroscopy. Meanwhile, the photovoltaic parameters were investigated by I-V measurements. The highest conversion efficiency is obtained when using a dye extracted from methanol solvent in combination with MgSO₄ additive, namely methanolic magnesium sulfate (MMSO). This higher power conversion efficiency is mainly attributed to the enhancement of the hydroxyl group in the MMSO dye solutions, which promotes higher dye adsorption and provides an organic dye passivation layer that reduces back-recombination in the cell. Furthermore, MgSO₄ aids in the replenishment of magnesium lost in the chlorophyll porphyrin ring during the degradation process. These combined effects have contributed to the overall conversion efficiency of the MMSO cell at 0.26 %, followed by 0.24 % for ethanolic magnesium sulfate (EMSO), respectively.

A comprehensive review of dye-sensitized solar cell optimal fabrication conditions, natural dye selection, and application-based future perspectives

Dye-sensitized solar cells (DSSC) constructed using natural dyes possess irreplaceable advantages in energy applications. The main reasons are its performance, environmentally benign dyes, impressible performance in low light, ecologically friendly energy production, and versatile solar product integration. Though DSSCs using natural dyes as sensitizers have many advantages, they suffer from poor efficiency compared to conventional silicon solar cells. Moreover, the difficulty in converting them to practical devices for the day-to-day energy needs has to be addressed. This review will outline the optimization of conditions to be followed for better efficiency in DSSCs using natural dyes as sensitizers. This review has taken into account the importance of the first step towards the fabrication of DSSC, i.e. the selection process. The selection of plant parts has a noticeable impact on the overall efficiency of the device. Accordingly, a proper study has been done to analyse the plant's parts that have shown better results in terms of device efficiency. In addition to this, a wide range of techniques and factors such as extraction methods, the solvent used, coating techniques, immersing time, and co-sensitization have been taken into consideration from the studies done over the period of 10 years to examine their influence on the overall performance of the DSSC device. These results have been addressed to stipulate the best suitable condition that will help supplement the efficiency of the device even further. Also, the future perspectives, such as the DSSCs use in wearable devices, incorporating various approaches to enhance the power conversion efficiency of DSSCs using natural dyes, and thermochromism ability for DSSCs have been discussed.

A Combined Experimental and Computational Study of Chrysanthemin as a Pigment for Dye-Sensitized Solar Cells

The theoretical study of chrysanthemin (cyanidin 3-glucoside) as a pigment for TiO₂-based dye-sensitized solar cells (DSSCs) was performed with the GAUSSSIAN 09 simulation. The electronic spectra of neutral and anionic chrysanthemin molecules were calculated by density functional theory with B3LYP functional and DGDZVP basis set. A better energy level alignment was found for partially deprotonated molecules of chrysanthemin, with the excited photoelectron having enough energy in order to be transferred to the conduction band of TiO₂ semiconductor in DSSCs. In addition, we used the raw aqueous extracts of roselle (Hibiscus sabdariffa) calyces as the source of chrysanthemin and the extracts with various pH values were tested in DSSCs. The extracts and photosensitized semiconductor layers were characterized by UV-Vis spectroscopy, and DSSCs based on raw extracts were characterized by current density-voltage measurements.

Optimizing a Simple Natural Dye Production Method for Dye-Sensitized Solar Cells: Examples for Betalain (Bougainvillea and Beetroot Extracts) and Anthocyanin Dyes

We present a study about the sensitizers extracted from natural resources. This paper focuses on how to select, extract and characterize natural dyes, giving some guides to establish a protocol for the whole process of fabricating and using these dyes. The influence of the extraction solvent and method, and of parameters such as pH are analyzed. Also, dye precursor and dye extract stability have been studied, as well as how the dye adsorbs onto substrates and the effect of mixing or concentrating the extracts. Results concerning betalain pigments present in bougainvillea and beetroot extracts, and anthocyanins in eggplant extracts, analyzed by using UV-Vis spectrometry, are included. As an example of application, we report procedures intended to test and enhance the dye potential as a main component of dye-sensitized solar cells (DSSCs). DSSCs mimic nature’s photosynthesis and have some advantages like an easy and low-cost fabrication procedure. Their efficiency depends on its design and fabrication process and also on the different components involved. Hence, optimizing each component is essential to achieve the best performance, and thus the dye used as a sensitizer is crucial. We fabricate cells by using a simple procedure: As the interest is focused on the sensitizer, the same consecutive steps are followed, varying only the dye extract. Among all the natural-dyes tested, beetroot extract reaches up to 0.47% cell efficiency, which is near the highest values found in literature for this pigment.

Structure and Photoelectrical Properties of Natural Photoactive Dyes for Solar Cells

A series of natural photoactive dyes, named as D1–D6 were successfully extracted from six kinds of plant leaves for solar cells. The photoelectrical properties of dyes were measured via UV-Vis absorption spectra, cyclic voltammetry as well as photovoltaic measurement. To theoretically reveal the experimental phenomena, the chlorophyll was selected as the reference dye, where the ground and excited state properties of chlorophyll were calculated via density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The experimental results show that the absorption peaks of those dyes are mainly distributed in the visible light regions of 400–420 nm and 650–700 nm, which are consistent with the absorption spectrum of chlorophyll. The photoelectrical conversion efficiencies of the solar cells sensitized by the six kinds of natural dyes are in the order of D1 > D4 > D2 > D5 > D6 > D3. The dye D1 performance exhibits the highest photoelectrical conversion efficiency of 1.08% among the investigated six natural dyes, with an open circuit voltage of 0.58 V, a short-circuit current density of 2.64 mA cm−2 and a fill factor of 0.70.