Idalia Gómez

Plant microbial fuel cells (PMFCs) represent an eco-friendly solution for generating clean energy by converting biological processes into electricity. This work presents the first integration of tin sulfide (SnS)-coated 304 stainless steel (SS304) electrodes into Aloe vera-based PMFCs for enhanced energy harvesting. SnS thin films were obtained via chemical bath deposition and screen printing, followed by thermal treatment. X-ray diffraction (XRD) revealed a crystal size of 15 nm, while scanning electron microscopy (SEM) confirmed film thicknesses ranging from 3 to 13.75 µm. Over a 17-week period, SnS-coated SS304 electrodes demonstrated stable performance, with open circuit voltages of 0.6–0.7 V and current densities between 30 and 92 mA/m², significantly improving power generation compared to uncoated electrodes. Polarization analysis indicated an internal resistance of 150 Ω and a power output of 5.8 mW/m². Notably, the system successfully charged a 15 F supercapacitor with 8.8 J of stored energy, demonstrating a practical proof-of-concept for powering low-power IoT devices and advancing PMFC applications beyond power generation. Microbial biofilm formation, observed via SEM, contributed to enhanced electron transfer and system stability. These findings highlight the potential of PMFCs as a scalable, cost-effective, and sustainable energy solution suitable for industrial and commercial applications, contributing to the transition toward greener energy systems. These incremental advances demonstrate the potential of combining low-cost electrode materials and energy storage systems for future scalable and sustainable bioenergy solutions.

Water-stable Cu₂S quantum dots were obtained by applying l-cysteine as a Cu(ii) to Cu(i) reducer and stabilizer in water and using an inert atmosphere at ambient temperature.

A graphene composite material suitable for facile drop-casting into flexible, conductive thin film electrodes from aqueous solution under ambient conditions is reported. This composite was applied to a polyethylene terephthalate substrate obtained from soda bottles. A solution of reduced graphene oxide with few layers (∼6 layers) was synthesized. The composites were prepared in two steps, first applying the reduced graphene oxide with surfactant and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) and then, solutions of poly-3-hexylthiophene with three different concentrations. Mild annealing was required only for the first step. The composite films exhibit more stability (mechanical and electrical) in bending tests when an intermediate amount of poly-3-hexylthiophene is applied. This composite is found attractive for flexible optoelectronic applications, promoting the reuse of one-use plastics.

In this paper two different methodologies for the assembling of organic-inorganic hybrid solar cells in 1D are presented: conventional and inverted. The conventional solar cell has the configuration of ITO/P3HT/ZnO/Au, while the inverted of ITO/ZnO/P3HT/Au. The active layers are composed of ZnO nanorods and P3HT nanorods. P3HT was synthesized by chemical oxidative polymerization and the nanorods were obtained by template assisted method. ZnO nanorods were synthesized by electrochemical method on ITO glass. The influence of the arrangement of the semiconductors was studied. The cathode of both solar cells was formed of gold nanoparticles (0D), synthesized by microwave method. The active layers were analyzed by UV–vis spectrophotometry, FTIR and SEM. Results of J-V curves indicate that the conventional solar cell has the highest current density due to the higher contact between the layers.

The influence of synthesis method, cycles quantity and sonication time in the gold nanoparticles size and plasmon resonance were analyzed to establish the synthesis with smaller nanoparticle size and higher absorbance. Gold nanoparticles were analyzed by UV-Vis spectrophotometry, dynamic light scattering (DLS) and surface electron microscopy (SEM). The results indicate that the nanoparticles obtained by microwave have bigger size but higher absorption. These nanoparticles were analyzed one year after its synthesis and it was found that the plasmon resonance signal remains almost unchanged. Finally, two equation were derived from the analyzes for estimate molar extinction coefficient, molar concentration and nanoparticle average diameter.