Although doped PEDOT was partially soluble in dimethylsulfoxide (DMSO), dimethylformamide (DMF) and THF, the dedoped PEDOT was not soluble in any organic solvent (Figure ). The solubility of doped PEDOT can be attributed to the highly doped nature of the polymer causing electrostatic and inductive interactions between the ionic species (and above mentioned polar solvents. Four-point electrical conductivity measurement was performed at room temperature using 1 mm thickness pellets of both doped and dedoped PEDOT (Figure ). While doped PEDOT was highly conductive, (1.6 S/cm), the dedoped PEDOT was non-conductive (3 x 10 -5 S/cm). The conductivity of doped PEDOT can be attributed to the dopant ions (bromide), thus, non-conductivity of dedoped PEDOT is due to the removal of these dopant ions after the neutralization reaction with hydrazine.monohydrate. UV-Vis-NIR (near-infrared) absorption and fluorescence spectra of doped PEDOT can be seen in Figure . Due to the highly conjugated nature of the polymer and significant solubility in DMSO (inset photo on left), doped PEDOT has absorption in the NIR region. When excited at 355 nm it showed a strong white light photoluminescence (inset photo on right) even in diluted solution (Figure ). Figure shows IR and NMR spectra of EDOT and doped PEDOT, respectively. In IR spectra, apart from the significant change in the fingerprint region, a clear broadening of the aliphatic C-H stretching peaks ~3000 cm 1 and disappearance of the aromatic C-H stretching peak ~3200 cm 1 indicate the successful polymerization of EDOT. In the comparison of NMR spectra of the monomer (EDOT) and doped PEDOT, the disappearance of the peaks in the aromatic region ~6.5 ppm and broadening of the aliphatic peaks also indicate the success of the photopolymerization reaction. Thermal stability of both doped and dedoped PEDOTs was probed using TGA under nitrogen atmosphere (Figure -S7). Doped PEDOT was thermally less stable than dedoped PEDOT due to the removal of dopant ions (bromine) during the heating process. However, both polymers showed high thermal stability (35% and 44% by weight left after 900 o C, respectively). Powder X-Ray diffractogram of both polymers were nearly identical and showed a highly amorphous nature due to the presence of high molecular weight polymers and lack of low molecular weight oligomers which have crystalline structures (Figure ). The only peak at 24 o corresponding to a d-spacing of ~4.9 Å can be attributed to typical  stacking which contributes to the conductivity of doped PEDOT. Finally, the redox potential of doped PEDOT was measured using cyclic voltammetry in order to calculate the band gap (Figure ). The oxidation and reduction potentials of doped PEDOT were measured as -0.02 V and -1.52 V, respectively. The calculated electronic band gap (Formula S1) was 1.50 eV which is typical for high molecular weight PEDOTs. Considering the UV-VIS-NIR absorption and the strong white light photoluminescence, the obtained doped PEDOT is a promising OPV material.