Growth of films with seven-coordinated diorganotin(IV) complexes and PEDOT:PSS structurally modified for electronic applications

This work refers to the manufacture and characterization of organic electronic devices made from seven-coordinated diorganotin(IV) complexes and the polymer poly(3,4-ethylenedyoxithiophene)-poly(styrene sulfonate) (PEDOT:PSS). In order to obtain the best electronic behavior, the devices were manufactured by spin-coating with seven-coordinated diorganotin(IV) complexes, synthetized with different peripheral substituents. The modification of the polarity in the molecule, from the presence of the different functional groups, is used as a way to enhance the charge transport inside the devices. Additionally, the devices received a post-treatment with isopropyl alcohol, in order to change the structure of PEDOT:PSS from benzoid form to quinoid form. The electric charge transport was evaluated from the current density-voltage characteristics, under dark and illuminated conditions. The devices present a mobility of ~10⁻⁹ cm²/Vs decreasing to values of ~10⁻¹¹-10⁻¹⁰ cm²/Vs. They display a photocurrent of ~10⁻⁷-10⁻⁸ A cm⁻² and a reduction is observed after the treatment. It is mainly the presence of the peripheral substituents in the diorganotin(IV) complexes, and not the polymer structure, that causes the electrical behavior of the device. The films made from seven-coordinated diorganotin(IV) complex particles deposited on the PEDOT:PSS, as well as their post-treatment, were characterized by Raman, ultraviolet-vis spectroscopy, scanning electronic microscopy and atomic force microscopy.