Development of Composite Semiconductor Films Based on Organotin Complexes Doped with Cobalt Porphine for Applications in Organic Diodes

In this work, we present the green synthesis of complex A–E derived from β-hidroxymethylidene indanones by ultrasound, which allowed for the obtaining of compounds in a shorter time and with good yields. These organotin complexes were then doped with cobalt porphine and incorporated into a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) matrix to manufacture composite semiconductor films. The semiconductor films were characterized through atomic force microscopy, examining their topography, Knoop hardness (around 17 HK), and tensile strength, which varied from 5 × 10⁻⁴ to 7 × 10⁻² Pa. The optical behavior was evaluated, revealing that the changes in these characteristics are related to the type of organotin complex present in the composite film: the transmittance ranged from 77% to 86%, while the reflectance varied from 13% to 17%. The band gap, calculated using the Kubelka–Munk function F(KM), was approximately 3.7 ± 0.19 eV for all the semiconductor films. Finally, we assessed the electrical behavior of the composite films through current–voltage (I–V) measurements under different lighting conditions. The I–V curves demonstrated that they share a saturation current density of 3.46 mA/mm². However, they differ in their conduction rates within the ohmic regimen. These composite films’ optical and electrical properties suggest their potential use in developing electronic devices like organic diodes.