Self-powered photo-thermo electrochemical sensor for harvesting of low photo thermal energy

An ecofriendly design of low-cost electrochemical sensor activated by low-grade photo-thermal energy can be a prime stepping-stone for the perspective developments of various renewable energy conversion and utilization schemes. In this study, an investigation of n-type indium arsenide (n-InAs)/aqueous solution of orange dye (OD)/Zinc (Zn) sensor was carried out at various molarities of 1, 2, and 3 mM of electrolytes under variable visible light illumination. OD was employed as a photo-active electrolyte, which is nontoxic and water-soluble organic semiconductor material. n-InAs was employed as a photoactive electrode while Zn was used as a counter metal electrode in our sensor configuration. The operation mechanism is based on the electrochemical-cell principle associated with photo-thermal energy splint. Photoinduced current-voltage characteristics, sensor stability, and a real-time transient characteristics were investigated using three different concentrations of electrolyte. A relatively improved response time was attained of 3 mM OD-electrolyte sensor with an inter-electrode distance of 3 mm under a light illumination of 95 mW/cm² and a temperature gradient of 1.5°C.