No abstract

Different types of natural dyes are commonly used to fabricate dyesensitized solar cells which are cheaper, simpler, and environmentally friendlier than conventional crystalline silicon solar cells. This paper objectifies the performance of locally grown natural dyes from Dhaka, Bangladesh using a simple fabrication design. Four natural dyes were obtained separately from spinach, turmeric, pomegranate, and beetroot which contain chlorophyll, curcumin, anthocyanin, and betanin pigments respectively. Ultraviolet-visible spectroscopy illustrated the optical properties of these dyes diluted in ethanol. Spinach and turmeric extracts showed sharper absorption peaks which qualify them as better sensitizers than pomegranate and beetroot extracts. Photoanodes (of thickness 15-20 μm) were prepared by employing the doctor blade technique on fluorine-doped tin oxides using TiO2 nanoparticles of anatase form and graphite coated fluorine-doped tin oxides were used as counter electrodes. The photoelectric measurements of the fabricated cells were done under air mass (AM) 1.5 and power density of 100 mW/cm2. The fabricated cell of turmeric extracted dye showed the highest efficiency of 0.031% (Open circuit voltage, VOC = 380 mV, Short circuit current density, JSC = 0.234 mA/cm2) and the cell using beetroot extract gave the highest fill factor (FF) of about 50% among the prepared dyesensitized solar cells. DUJASE Vol. 7(1) 38-44, 2022 (January)

In this work, a dual-axis automated solar tracker is developed by using two linear motors, four light dependent resistors (LDRs) and two mono crystalline solar panels. The LDRs are placed on the rotating frame where the solar panels are placed to detect the position of the sun and the controller circuit drives the motors to place the frame towards the sun. The controlling unit has been developed using PLC microcontroller. The motor driver circuit has been designed using a code to align the solar panels to a suitable position so that it is exposed to the maximum amount of solar irradiance. The driver circuit receives data from the LDRs and the microcontroller controls the motors to move the panel along its horizontal and vertical axis. To evaluate the performance of the solar tracker, output power of the solar tracker and an identical set of static solar panels set in an optimum fixed orientation are measured from the open-circuit voltage and the short circuit current for two consecutive days. The output power produced by the automatic solar tracker was consistently higher than that by the static solar panel. The energy gain due to using the automatic solar tracker is at highest in the morning and in the afternoon at almost 40%. The lowest value of energy gain is observed during noon at as low as 1%. The average increase in output throughout the day is 24.09%.