RESUMEN
Bulk and surface trap-states in the Sb2S3films are considered one of the crucial energy loss mechanisms for achieving high photovoltaic performance in planar Sb2S3solar cells. Because ionic liquid additives offer interesting physicochemical properties to control the synthesis of inorganic material, in this work we propose the addition of 1-Butyl-3-methylimidazolium hydrogen sulfate (BMIMHS) into a Sb2S3hydrothermal precursor solution as a facile way to fabricate low-defect Sb2S3solar cells. Lower presence of small particles on the surface, as well as higher crystallinity are demonstrated in the BMIMHS-assisted Sb2S3films. Moreover, analyses of dark current density-voltageJ-Vcurves, surface photovoltage transient and intensity-modulated photocurrent spectroscopy have suggested that adding BMIMHS results in high-quality Sb2S3films and a successful defect passivation. Consequently, the best-performing BMIMHS-assisted device exhibits a 15.4% power conversion efficiency enhancement compared to that of control device. These findings show that ionic liquid BMIMHS can effectively be used to obtain high-quality Sb2S3films with low-defects and improved optoelectronic properties.
RESUMEN
To achieve superior photovoltaic performance on Sb2S3 solid state solar cells (ssSCs), the concomitant development of efficient hole transport materials (HTMs) is required. Herein, a novel solution processed HTM obtained by mixing NiOx nanoparticles (NiOx-NP) and poly(3-hexylthiophene) (P3HT) is reported. These P3HT:NiOx-NP nanocomposite HTMs were obtained with different controlled concentrations of NiOx-NP using a common solvent. Incorporation of NiOx-NP significantly impacts on the structural and hole-transport layer properties of the nanocomposite films, which in turn contributes to improve the photovoltaic performance of the corresponding devices. Thus, Sb2S3 ssSCs based on HTM with an optimum concentration of NiOx-NP in P3HT, i.e. P3HT:2% NiOx-NP, yield a 50% improvement in the power conversion efficiency relative to control devices fabricated with pristine P3HT. The improved hole separation and injection at the Sb2S3/HTM interface, determined by steady-state photoluminescence quenching and electrochemical impedance spectroscopy studies, correlate well with the higher hole mobility of the nanocomposite and the current density and fill factor enhancements.