Potassium selenotrithionate – the precursor for formation of semiconductive and conductive copper selenide layers on polyamide surface

Abstract

Semiconducting and electrically conductive layers of copper selenide, CuxSey, on the polyamide 6 (PA) surface were formed using the sorption–diffusion method and the water solutions of potassium selenotrithionate, K2SeS2O6, as the precursor of polymer seleniumization. Selenotrithionate anions containing divalent selenium atoms of low oxidation state, –O3S-Se-SO3–, are sorbed-diffused into PA films if they are treated with selenotrithionate solutions. The concentration of sorbed selenotrithionate increases with an increase of the temperature and concentration of the precursor solution and the duration of PA treatment. CuxSey layers are formed on the surface of a PA film when a chalcogenized polymer is treated with the water solution of copper(II/I) salt: the anions of selenotrithionate react with copper ions. The concentration of copper increases with increasing the concentration and temperature of the precursor solution and the duration of PA initial chalcogenization. The formed layers were characterized for chemical composition, electrical and physical properties. The percentage amounts of selenium and copper in CuxSey layers on PA films with polymer seleniumization time changed as follows: Se from 51.61 to 69.46% and Cu from 48.39 to 30.54%. The most uniform thin layer of CuxSey formed on the polyamide film being seleniumized for 2.5 h was observed by scanning electron microscopy (SEM). The thickness of CuxSey layers depends on polymer seleniumization time and changed in an interval of 0.98–3.2 μm. The X-ray diffraction (XRD) pattern study of CuxSey layers showed that they are polycrystalline in nature; six phases of copper selenides Cu2Se (27-1131), CuSe2 (74-280), CuSe2 (18-453), Cu3Se2 (72-1421) and the phases of berzellianite Cu2-xSe (6-680) and of bellidoite Cu2Se (29-575) were identified. The XPS results confirmed the formation of copper selenides layers on the surface of PA. The regularities established enable the formation of CuySey layers of a desirable composition and conductivity.