AUTHOR=Sánchez Vergara María Elena , Zubillaga Serrano Rafael Imanol , Hamui Leon , Galván Hidalgo José Miguel , Cosme Ismael , Gómez Elizabeth 

TITLE=Improved Functionality of Poly(3,4-Ethylenedioxythiophene):Poly(Styrenesulfonate)/HeptaCoordinated Organotin Complex Films via Graphene Applied to Organic Solar Cell Fabrications

JOURNAL=Frontiers in Materials

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.860859

DOI=10.3389/fmats.2022.860859

ISSN=2296-8016

ABSTRACT=Enhanced transparency, conductivity and stability are some of the most important factors to consider in order to prepare transparent electrodes (TEs) and hole transport layer (HTL) for organic solar cells. In this study, the transparency, optical and electrical behavior of hybrid films formed by poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and heptacoordinated organotin (IV) complexes were improved by introducing graphene. The films were deposited by spin-coating and subsequently characterized by Infrared and Raman spectroscopy, as well as by scanning electron microscopy (SEM) and atomic force microscopy (AFM). All the hybrid films transmitted more than 70% of light in the 600-1000 nm wavelength region and the optical band gap obtained is in the range of 2.64 and 3.09 eV. Besides, bathophenanthroline (BPhen) was introduced as an electron transport layer (ETL) in order to study the solar cell with complete architecture, conformed by glass/ITO/PEDOT:PSS-graphene-complex/BPhen/Ag. By incorporating the BPhen, the J-V curve current density values were increased, showing a conductivity change of as much as 2.1 × 10-4 S/cm, and under illuminated conditions a more pronounced J-V curve variation (as much as 2.5 × 101 A/cm2) was observed. In closing, the devices were subjected to accelerated lighting conditions, to determine the stability and the operating capacity of the solar cells. The electrical behavior of the devices changed. Within the first 2 hours, the electrical behavior improved, where organotin complex without substituent (complex-a) device presents higher stability than complex with chloride substituent (complex-b) device, due to the chloride radical interacting with the BPhen. However, the electrical behavior degraded after 4 hours almost 8 orders of magnitude in current density due to device films and interfaces degradation.