4 research outputs found

    Effect of stabilizer on optical band gap of ZnO and their performance in dye-sensitized solar cells

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    ABSTRACT. In dye-sensitized solar cells, transparent metal oxide working electrodes play a vital role in defining the power conversion efficiency. It was found that the size of nanoparticles influences the electrical, optical properties of these electrodes. Herein, we describe the synthesis of ZnO with zinc acetate dihydrate and different stabilizers (diethylamine and triethylamine) by using a modified solvothermal process. The obtained materials were characterized by XRD, SEM, EDX, TEM, HRTEM, UV-visible, FTIR, and Raman methods. The crystallite sizes for ZnO-1 and ZnO-2 samples were indexed as 39.0 and 40.5 nm for the highest peak intensity with diethylamine and triethylamine stabilizer, respectively. We examine the effect of stabilizers on the morphology, optical band gap, and photovoltaic performance of the prepared ZnO. We found that ZnO prepared using diethylamine stabilizer exhibiting significant efficiency of 1.45%, open-circuit voltage 0.454 V, short-circuit current density 2.128 mA/cm2, and 0.66 fill factor were achieved under 44 mW/cm2 illumination powers with dye-3.                 KEY WORDS: Dye-sensitized solar cells, ZnO, Band gap, Photovoltaic performance   Bull. Chem. Soc. Ethiop. 2022, 36(1), 209-222.                                                        DOI: https://dx.doi.org/10.4314/bcse.v36i1.17                                                     &nbsp

    Evaluation of humidity sensing properties of TMBHPET thin film embedded with spinel cobalt ferrite nanoparticles

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    In this study, we report the enhanced sensing parameters of previously reported TMBHPET-based humidity sensor. Significant improved sensing performance has been demonstrated by coupling of TMBHPET moisture sensing thin film with cobalt ferrite nanoparticles (synthesized by eco-benign ultrasonic method). The mean size of CoFe2O4 nanoparticles has been estimated to be ~ 6.5 nm. It is assumed that the thin film of organic–ceramic hybrid matrix (TMBHPET:CoFe2O4) is a potential candidate for humidity sensing utility by virtue of its high specific surface area and porous surface morphology (as evident from TEM, FESEM, and AFM images). The hybrid suspension has been drop-cast onto the glass substrate with preliminary deposited coplanar aluminum electrodes separated by 40 µm distance. The influence of humidity on the capacitance of the hybrid humidity sensor (Al/TMBHPET:CoFe2O4/Al) has been investigated at three different frequencies of the AC applied voltage (Vrms ~ 1 V): 100 Hz, 1 kHz, and 10 kHz. It has been observed that at 100 Hz, under a humidity of 99 % RH, the capacitance of the sensor increased by 2.61 times, with respect to 30 % RH condition. The proposed sensor exhibits significantly improved sensitivity ~560 fF/ % RH at 100 Hz, which is nearly 7.5 times as high as that of pristine TMBHPET-based humidity sensor. Further, the capacitive sensor exhibits improved dynamic range (30–99 % RH), small hysteresis (~2.3 %), and relatively quicker response and recovery times (~12 s, 14 s, respectively). It is assumed that the humidity response of the sensor is associated with the diffusion kinetics of water vapors and doping of the semiconductor nanocomposite by water molecules
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