Natural Dyes as Photosensitizers for Dye-sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) were assembled using Zinc oxide (ZnO) nanoparticles as a photoelectrode and natural dyes extracted from eight natural plants as photosensitizers. The structural properties of the synthesized ZnO nanoparticles were studied using XRD, SEM and TEM characterizations. Photovoltaic parameters such as short circuit current density Jsc, open circuit voltage Voc, fill factor FF, and overall conversion efficiency η for the fabricated cells were determined under 100 mW/cm2 illumination. It was found that the DSSC fabricated with the extracted safflower dye as a sensitizer showed the best performance. Also, its performance increased with increasing the sintering temperature of the semiconductor electrode with highest performance at 400 °C. Moreover, it was found that a semiconductor electrode of 7.5 μm thickness yielded the highest response

Research Article Dye-Sensitized Solar Cells Using Fifteen Natural Dyes as Sensitizers of Nanocrystalline TiO 2 Monzir S. Abdel-Latif Department of Chemistry, Islamic University …

In this study, dye-sensitized solar cells were fabricated using TiO 2 as a semiconducting layer dyed with natural extracts. Thin layers of nanocrystalline TiO 2 were deposited on transparent Fluorine doped tin oxide (FTO) conductive glass using doctor blade method. Fifteen natural dyes were examined as photosensitizers of the TiO 2 layer. The absorption spectra of the natural extracts were performed. The JV characteristic curves of all fabricated cells were measured and analyzed. The parameters related to the cell performance were presented. Moreover, the impedance spectroscopy of two cells was investigated

Abdel-Latif, “Dye-sensitized solar cells based on ZnO films and natural dyes

Abstract This work emp loys extracts fro m Walnuts, Rhubarb, and Po megranate as natural dyes for fabricat ion of dye-sensitized solar cells (DSSCs). ZnO nanoparticles with crystallite mean value 12 n m as confirmed fro m XRD data have been synthesized at pH 12. SEM p icture of the ZnO powder reveals ho mogeneous and well defined nanoparticles with size of about 15 n m. TEM micrograph shows that the powder has a porous agglomerate structure consisting main ly of spherical crystalline particles with about 15-20 n m diameter. ZnO films were deposited on Fluorinated Tin Oxide (FTO) coated glass sheets followed by sintering at 450℃. The samples were sensitized by soaking in the dye solution. A Graphite slab was used as a back electrode, and redo x was employed as an electrolyte. Each cell was illu minated with light intensities in the range 40,000-100,000 Lux to measure the photovoltaic parameters. The experimental results shows that the highest I sc value is obtained fro m the DSSC sensitized with Rhubarb extract while the highest V oc value is obtained from the DSSC sensitized with the Walnuts extract. The P max of the DSSC sensitized by the Walnuts extract is greater than those sensitized by Rhubarb and Po megranate ext racts. Moreover, the open circuit voltage V oc decay was found to closely fo llo w a pseudo single exponential form

Enhancement of the performance of dye-sensitized solar cells using sensitized zinc oxide nanoparticles by rhodamine B dye

In the present work, ZnO nanoparticles were synthesized via a simple wet chemical (hydrothermal) technique using zinc acetate dihydrate (Zn(CH3COO)2.2H2O) as a row material dissolved into absolute methanol and aqueous NaOH as precipitation agent. The X-ray diffractometer (XRD) patterns showed a standard hexagonal wurtzite structure of ZnO NPs with average particle size of about 28±2 nm. High resolution-transmission electron microscopy (HR-TEM) micrograph of ZnO NPs showed semi-spherical particles with an average size of about 25.3±6 nm, which agreed well with the XRD results. UV-Vis spectrum of the ZnO NPs revealed the highest absorption band at 366.4 nm and the optical energy gap (Eg) was about 3.12 eV. The Photoluminescence spectrophotometer (PL) spectrum emission illustrated lower UV emission than the visible emission. This indicated to the high defect density in ZnO sample. The effect of concentration of cost-effective Rhodamine B dye on the performance of dye-sensitized solar cells) DSSCs) based on ZnO NPs has been studied. The best performance among the five concentrations was 0.7 mM. The photon to electric energy conversion efficiency of the DSSCs has been found to increase by eight times from 0.07 to 0.58 %. Transient open-circuit voltage decay (TOCVD) method has been used to investigate the electron lifetime (τn) and the electron recombination velocity (Krec) in DSSCs, by using the double exponential function. The results revealed that the Rhodamine B dye can be an efficient dye as a low-cost sensitizing dye for DSSCs.In the present work, ZnO nanoparticles were synthesized via a simple wet chemical (hydrothermal) technique using zinc acetate dihydrate (Zn(CH3COO)2.2H2O) as a row material dissolved into absolute methanol and aqueous NaOH as precipitation agent. The X-ray diffractometer (XRD) patterns showed a standard hexagonal wurtzite structure of ZnO NPs with average particle size of about 28±2 nm. High resolution-transmission electron microscopy (HR-TEM) micrograph of ZnO NPs showed semi-spherical particles with an average size of about 25.3±6 nm, which agreed well with the XRD results. UV-Vis spectrum of the ZnO NPs revealed the highest absorption band at 366.4 nm and the optical energy gap (Eg) was about 3.12 eV. The Photoluminescence spectrophotometer (PL) spectrum emission illustrated lower UV emission than the visible emission. This indicated to the high defect density in ZnO sample. The effect of concentration of cost-effective Rhodamine B dye on the performance of dye-sensitized solar cells) DSSCs) based on ZnO NPs has been studied. The best performance among the five concentrations was 0.7 mM. The photon to electric energy conversion efficiency of the DSSCs has been found to increase by eight times from 0.07 to 0.58 %. Transient open-circuit voltage decay (TOCVD) method has been used to investigate the electron lifetime (τn) and the electron recombination velocity (Krec) in DSSCs, by using the double exponential function. The results revealed that the Rhodamine B dye can be an efficient dye as a low-cost sensitizing dye for DSSCs

Perovskite solar cells free of hole transport layer

In this work, easy and simple structured perovskite solar cells (PSCs) are designed and characterized. Our effort was to reduce the cost of the fabrication of such PSC devices, first by using an inexpensive starting precursor (aqueous methylamine solution) for the perovskite materials and second by design in a PSC structure free of the expensive hole transport layer (HTL). The CH3NH3PbI3 perovskite sols were deposited onto a conductive FTO glass using the spin coating technique followed by heating at 100 °C for 10 min. The structure of the films was characterized by X-ray diffraction (XRD) and their optical properties by UV–VIS spectrophotometry and photoluminescence (PL). The obtained phase confirmed the formation of a tetragonal perovskite structure. Two different solvents have been used, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The effect of the type and the concentration of the used solvent DMF and DMSO on the performance of the solar cells have been investigated. It was found that a 40% concentration of the perovskite material resulted in the optimum film thickness that gives the best photoelectric performance. The DMF-based PSC assembled solar cell exhibited the best performance with an open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2, and an overall photon to electric conversion efficiency of 5.7%; all these results are higher than those of cells made with DMSO.This work was supported financially partially by the PHC Al Maqdisi Grant No. 37038WF and the Palestinian German Joint Research Project PALGER2015-34-012. The authors would like to thank Mr. Ahmad Ashour for his assistance in UV–VIS measurements.In this work, easy and simple structured perovskite solar cells (PSCs) are designed and characterized. Our effort was to reduce the cost of the fabrication of such PSC devices, first by using an inexpensive starting precursor (aqueous methylamine solution) for the perovskite materials and second by design in a PSC structure free of the expensive hole transport layer (HTL). The CH3NH3PbI3 perovskite sols were deposited onto a conductive FTO glass using the spin coating technique followed by heating at 100 °C for 10 min. The structure of the films was characterized by X-ray diffraction (XRD) and their optical properties by UV–VIS spectrophotometry and photoluminescence (PL). The obtained phase confirmed the formation of a tetragonal perovskite structure. Two different solvents have been used, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The effect of the type and the concentration of the used solvent DMF and DMSO on the performance of the solar cells have been investigated. It was found that a 40% concentration of the perovskite material resulted in the optimum film thickness that gives the best photoelectric performance. The DMF-based PSC assembled solar cell exhibited the best performance with an open circuit voltage of 750 mV, a photocurrent density of 12.5 mA/cm2, and an overall photon to electric conversion efficiency of 5.7%; all these results are higher than those of cells made with DMSO