Dye-sensitized solar cells (DSSCs) are made of manganese dioxide (MnO2) and Ag-doped manganese dioxide (Ag-MnO2) counter electrodes (CEs). Herein, MnO2 and Ag-MnO2 were synthesized using the ...hydrothermal method and deposited through the drop casting technique. Electrical characterizations were performed to obtain the fill factor (FF), short-circuit current density (JSC), open-circuit voltage (VOC), and power conversion efficiency (PCE). Frequency- and voltage-dependent impedance spectroscopy were performed to gain an insight into the charge transport characteristics. DSSCs fabricated with a MnO2-coated electrode gave a PCE of 2.86% with a VOC of 0.60 V and a JSC of 8.72 mA/cm2, while DSSCs fabricated with Ag-MnO2 CEs demonstrated a higher PCE of 3.05%, with a VOC of 0.66 v and a JSC of 13.3 mA/cm2. The obtained results indicate that Ag-doped MnO2-coated counter electrodes have the potential to replace expensive Pt=coated counter electrodes.
Improvement in panchromatic light-harvesting and photovoltaic performance is reported for dye-sensitized solar cells by adopting co-sensitization technique by mixing dyes. Betalain and Anthocyanin ...natural dyes are extracted from beetroot and cranberries. All dyes are characterized by UV–Vis and FTIR spectroscopy. Solar cells are fabricated and electrical characterizations are performed. Solar cell sensitized with mixed dyes demonstrated improved performance compared to cells of individual dyes, and yielded short circuit current density, open circuit voltage and fill factor of 0.36 mA/cm2, 0.42 V and 0.51 respectively. Their maximum efficiency is 5.37 and 1.16 times higher than that of individual beetroot and cranberry dye DSSCs respectively. Charge transfer processes are studied by impedance spectroscopy characterizations. The obtained results are in close agreement with commercially available N3 dye DSSC. The results yield that mixing dyes from different natural sources can be a very effective to further improve the performance of DSSCs.
Photoelectrical characterization and impedance spectroscopy are performed for Dye sensitized solar cells (DSSC) fabricated by using natural dye (Pomegranate extract) and metallic dye (N719). Dyes are ...characterized by ultraviolet–visible spectroscopy to study optical properties. Typical photovoltaic behaviors are observed with open circuit voltage of 0.52 and 0.7 V and short circuit current density of 0.34 and 14 mA/cm2 for natural and metallic dyes based cells respectively. From current–voltage (I-V) measurements, fill factor, conversion efficiency and ideality factor are extracted. Electrical properties of the cells are investigated using Mott-Schottky plots. To gain insight into charge transport, voltage and frequency dependent impedance spectroscopy is performed. Photovoltaic performance of cells is evaluated from the trends of recombination resistance and chemical capacitance in the measured impedance spectra. Significant contribution of interface trap states is observed at low frequencies and reversal of the polarity of capacitance from positive to negative values is observed at higher frequencies. The overall behavior of devices is compared. To our knowledge these impedance spectroscopy results for natural dye based solar cell are not reported earlier. Their insight and understanding is important for optimizing various components and interfaces for the development of cost effective commercially available natural dyes based DSSCs.
One of the biggest environmental challenges for scientists and researchers is to minimize energy crisis by utilizing renewable energy without impacting the climate. Natural dyes based organic solar ...cells are third generation dye sensitized solar cells (DSSC) which are bio safe, low cost, and relatively easy to fabricate with flexibility than Silicon based solar cells. In this study dye sensitized solar cells are modelled and simulated using diffusion model. The simulations are carried out in MATLAB software to investigate the electrical characteristics. The simulations are performed for three different DSSCs made of pomegranate, beetroot and N-719 dyes. Physical parameters are extracted and their impact on the performance of solar cells is studied. Additionally, the effects of variations in electrode thickness and irradiance are also investigated. The results indicated that short-circuit current, open-circuit voltage and output power increased by decreasing the electrode thickness. Simulated results are in good agreement with the experimental results of preassembled DSSCs. A set of parameters based on electrical considerations is delivered which will not only help to study the impact of physical parameter of DSSC but will also help to control and improve the performance and efficiency of Dye sensitized solar cells.
