Fabrication of Dye-Sensitized Solar Cells (DSSCs) Using Natural Materials for Powering IoT Devices

Abstract

The rapid growth of Internet of Things (IoT) networks makes it tough to keep all those sensor nodes powered, creating a need for smart, eco-friendly solutions. Dye-sensitized solar cells (DSSCs) have drawn a lot of interest because they're easy to make, work surprisingly well under indoor lights, and can even use natural biodegradable dyes. What's clever is how they mimic photosynthesis: a dye-coated layer of titanium dioxide (TiO₂) captures light, instead of relying on conventional silicon. Right now, researchers are pushing further by exploring both n-type TiO₂ and p-type nickel oxide (NiO_x) structures, giving engineers more options as this technology edges closer to real-world use. This study systematically evaluated 15 locally available botanical dye sources from the Medina region of Saudi Arabia as photosensitizers for n-type DSSCs. The sources included eight plant-derived dyes (turmeric, black tea, cinnamon, henna, hibiscus, cardamom, cumin, and saffron) and seven fruit-derived dyes (Ajwa dates, beetroot, Turkish coffee, Arabic coffee, pomegranate, cacao, and tamarind). The open-circuit voltage (V_oc) was measured under 100 mW cm⁻² AM 1.5G illumination (n = 5 per dye). Statistical analysis using one-way ANOVA, Tukey HSD, and Fisher LSD post-hoc tests revealed that the plant-based dyes showed no significant differences in performance (F = 1.064, p = 0.429), whereas the fruit-based dyes exhibited highly significant variation (F = 7.375, p = 0.00104). Ajwa date extract achieved the highest V_oc (median 0.42 V; maximum 0.50 V), while Turkish coffee demonstrated the lowest fabrication variance (0.00066). An illustrative LTspice simulation of the LTC3108 converter, using a simplified ideal-source representation, suggests that natural DSSC outputs of 0.3–0.4 V could in principle be boosted to a regulated 2.2 V output for duty-cycled wireless IoT sensor nodes; confirmation under indoor illumination (200–500 lx) with a calibrated device model remains to be performed. On this basis, Ajwa dates and Turkish coffee are identified as leading candidate natural sensitizers warranting full photovoltaic and indoor-illumination characterization for potential use in locally manufactured IoT energy harvesters.