International audienc

International audienc

In this work, we propose poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) material to form a hybrid heterojunction with amorphous silicon-based materials for high charge carrier collection at the frontal interface of solar cells. The nanostructural characteristics of PEDOT:PSS layers were modified using post-treatment techniques via isopropyl alcohol (IPA). Atomic force microscopy (AFM), Fourier-transform infrared (FTIR), and Raman spectroscopy demonstrated conformational changes and nanostructural reorganization in the surface of the polymer in order to tailor hybrid interface to be used in the heterojunctions of inorganic solar cells. To prove this concept, hybrid polymer/amorphous silicon solar cells were fabricated. The hybrid PEDOT:PSS/buffer/a-Si:H heterojunction demonstrated high transmittance, reduction of electron diffusion, and enhancement of the internal electric field. Although the structure was a planar superstrate-type configuration and the PEDOT:PSS layer was exposed to glow discharge, the hybrid solar cell reached high efficiency compared to that in similar hybrid solar cells with substrate-type configuration and that in textured well-optimized amorphous silicon solar cells fabricated at low temperature. Thus, we demonstrate that PEDOT:PSS is fully tailored and compatible material with plasma processes and can be a substitute for inorganic p-type layers in inorganic solar cells and related devices with improvement of performance and simplification of fabrication process.

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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.

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