Tuning the photo-luminescence and anisotropic structure of PEDOT
In the current work we study the photoluminescence and anisotropic structure of PEDOT which is obtained in the presence of ions that perturb water structure (ions in Hofmeister series). The water content in PEDOT has been confirmed by TGA and DSC measurements. The weight loss and heat flux together provided refined information about water content in synthesized PEDOT, and based on the characteristic energy value, we conclude that water molecules are bonded to PEDOT chains by the hydrogen bond. Physicochemical properties of such prepared PEDOT have been studied, e.g. the presence of photoluminescence is observed for PEDOT in the solid-state (thin film) with the longest Stokes shift (273 nm). Similarly, photoluminescence has been detected for aqueous PEDOT suspension with the life-time of the excited state in the range of nanoseconds. Moreover, PEDOT chains can undergo rearrangements under electrochemical performance with the formation of anisotropic structure, which is confirmed by polarized microscopy and XRD measurements. The photoluminescence spectrum of anisotropic PEDOT film contains sharp, well resolved peaks.