Influence of Sulfurization Time on Sb2S3 Synthesis Using a New Graphite Box Design.

In recent years, antimony sulfide (Sb2S3) has been investigated as a photovoltaic absorber material due to its suitable absorber coefficient, direct band gap, extinction coefficient, earth-abundant, and environmentally friendly constituents. Therefore, this work proposes Sb2S3 film preparation by an effective two-step process using a new graphite box design and sulfur distribution, which has a high repeatability level and can be scalable. First, an Sb thin film was deposited using the RF-Sputtering technique, and after that, the samples were annealed with elemental sulfur into a graphite box, varying the sulfurization time from 20 to 50 min. The structural, optical, morphological, and chemical characteristics of the resulting thin films were analyzed. Results reveal the method's effectivity and the best properties were obtained for the sample sulfurized during 40 min. This Sb2S3 thin film presents an orthorhombic crystalline structure, elongated grains, a band gap of 1.69 eV, a crystallite size of 15.25 Å, and a nearly stoichiometric composition. In addition, the formation of a p-n junction was achieved by depositing silver back contact on the Glass/FTO/CdS/Sb2S3 structure. Therefore, the graphite box design has been demonstrated to be functional to obtain Sb2S3 by a two-step process.

Interface fails and Young's module approximation of multilayer flexible devices through finite element method.

Electronic flexible devices are prone to degrade their electrical performance or lose functionality when subjected to deformations. Brittle fracture is a common damaging effect observed in devices composed of low-thickness layered materials stacked onto a flexible substrate by dissimilar mechanical properties interaction. This work studies the mechanical behavior of Organic Flexible Solar Cells (OFSC) with a heterostructure PET/ITO/P3HT:PCBM/Ag subjected to uniaxial displacements through an experimental and numeric point of view. Experimental showed that damage proceeds in two ways. First, the formation of a grid crack pattern begins at the ITO layer, and second, the delamination in the ITO/P3HT:PCBM interface. The numerical model analyzed the force and displacements and the absorption/dissipation of strain energy on layers and interfaces of the device. The comparison of the global Young's module for experimental and numeric studies validated the numeric analysis, with results of 4.16 ± 0.05 GPa for experimental and 4.36 ± 0.15 GPa for numeric. Additionally, the model associates the ITO layer with the highest strain energy dissipation or the most prone to failure, which agrees with the experiments. Then, the model successfully predicts the mechanical behavior of OFSC and represents a valuable tool for studying flexible devices and predicting the appearance of mechanical damage when subjected to uniaxial deformations, even being able to avoid potential damage changing parameters such as the thickness of the layers.