Electron. Mater. Lett., Vol. 11, No. 2 (2015), pp. 259-265 Thermo Photo-Electrochemical Effect in n-InP/Aqueous Solution of Orange Dye/C Cell Taimoor Ali, 1, * Khasan S. Karimov, 1,2,3 Khakim M. Akhmedov, 2 K. Kabutov, 3 and Amjad Farooq 1 1 GIK Institute of Engineering Sciences and Technology, Topi, 23640, Pakistan 2 Center for Innovative Development of Science and New Technologies, Academy of Sciences, Rudaki Ave.33, Dushanbe, 734025, Tajikistan 3 Physical Technical Institute of Academy of Sciences, Aini St.299/1, Dushanbe, 734063, Tajikistan (received date: 10 June 2014 / accepted date: 1 November 2014 / published date: 10 March 2015) 1. INTRODUCTION Energy conversion is a key factor of economy. Energy demand can be fulfilled by utilizing the energy in efficient way. Oil has been a primary energy resource for many decades. World Energy Council (WEC) estimated that in year 2020 the world energy demand would be raised up to 50 - 80% more than 1990 levels. [1] An efficient energy system is based on a cost effective renewable and non- polluting source of energy. [2] Due to the limitation of nuclear resources and fossil fuels, novel renewable technologies that are eco-friendly will lead to a long term energy resource. [3] Among these renewable energies, solar energy fulfills the demand of energy more efficiently than other renewable resources because total solar flux absorbed at the sea level by the earth, i.e. ~1.2 × 10 17 W which can meet our present and future energy requirements. [4] Energy harvesting from waste heat of power plants, buildings and vehicles can effectively improve energy efficiency. [5-7] Several thermoelectric [8-11] and thermo electrochemical cell (TEC) have been studied and reported which convert waste heat into electricity. [12-16] Solid state junction devices made of silicon are expensive; therefore, low cost solution processed power devices are more suitable for power generation. [17-20] Recently, Pablo et al. have investigated the design and optimization of TEC while considering a flow cell thermocell design. [21] Similarly photo-electrochemical cell (PEC) is solar based renewable energy device which is eco-friendly and uncomplicated that can be used at both small and larger scale as a potential candidate in this regard. [22] The organic semiconductor energy devices are cost effective, reliable and non-polluting devices. Organic semi- conductor based electronic devices have developed a greater interest and are being used over the last few decades. [23] A number of organic semiconductor based electronic and optoelectronic devices have been studied including sensors [24] The effect of light and heat is studied on the electrical properties of an electrochemical n-InP/aqueous solution of orange dye/C cell. The cell is investigated under the light and heat of filament bulb. The n-type indium phosphide and carbon plates are used as electrodes. The aqueous solution of organic material orange dye (C H N O ) in distilled water is served as electrolyte at 1, 3 and 5 wt. % concentration. The cell is assembled in sealed organic glass box with dimensions 35 × 13 × 14 mm. The open circuit voltage (V ) and short circuit current (I ) of the cell are observed by illuminating and heating the samples. The temperature is raised up to 60°C from 25°C when light intensity is increased from dark condition to 425 W/m . It is observed that the relationship between light intensity and temperature is approximately linear for all cases. The V and I increase 100% and 300% respectively by increasing the light. The reported n-InP/ aqueous solution of orange dye/C cell can be considered as small converter of light and heat into electric power. Keywords: solution processed solar cell, orange dye, n type indium phosphide, thermo-electrochemical, photo-electrochemical cell DOI: 10.1007/s13391-014-4182-7 *Corresponding author: taimoor_ali29@live.com ©KIM and Springer