Thermoelectric (TE) materials convert waste heat into electricity; hence, this is foreseen as a possible source of green energy. The transformation of energy by TE generators has several advantages, namely they operate without moving parts, do not create noise, are less bulky, environment friendly, and may be coupled with other modes of energy generation. Compared to traditional TE materials like bismuth telluride or other metal oxides, polymeric materials are much easier to be fabricated into devices. Thus, there is a growing interest in such materials. PEDOT:PSS (1:2.5 by wt.) is one of the commercially available conducting polymers. However, it has relatively low electrical conductivity (σ) and Seebeck coefficient (S) and, hence, low power factor (S2σ). Vitamin C (L-ascorbic acid) is a natural weak acid which is found in citrus fruits, vegetables, etc. Previously, the use of mineral acids like sulfuric acid, hydrochloric acid etc., and organic solvents like dimethyl sulfoxide, ethylene glycol etc. for improving TE properties has been investigated, however, these compounds are not environment friendly. In view of environmental safety, in this study, the effect of vitamin C concentration (0-10 wt%) on electrical conductivity and Seebeck coefficient of PEDOT:PSS is investigated. It is found that vitamin C increased the electrical conductivity without negatively affecting the Seebeck coefficient. Hence, it could improve the power factor (~0.2 µW/mK2) of the conducting polymer, eventually increasing the efficiency of TE generators.