Co-grafting of porphyrins and fullerenes on ZnO nanorods: Towards supramolecular donor–acceptor assembly

Stretchable, Breathable, and Stable Lead-Free Perovskite/Polymer Nanofiber Composite for Hybrid Triboelectric and Piezoelectric Energy Harvesting

Halide-perovskite-based mechanical energy harvesters display excellent electrical output due to their unique ferroelectricity and dielectricity. However, their high toxicity and moisture sensitivity impede their practical applications. Herein, a stretchable, breathable, and stable nanofiber composite (LPPS-NFC) is fabricated through electrospinning of lead-free perovskite/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and styrene-ethylene-butylene-styrene (SEBS). The Cs₃ Bi₂ Br₉ perovskites serve as efficient electron acceptors and local nucleating agents for the crystallization of polymer chains, thereby enhancing the electron-trapping capacity and polar crystalline phase in LPPS-NFC. The excellent energy level matching between Cs₃ Bi₂ Br₉ and PVDF-HFP boosts the electron transfer efficiency and reduces the charge loss, thereby promoting the electron-trapping process. Consequently, this LPPS-NFC-based energy harvester displays an excellent electrical output (400 V, 1.63 µA cm^-2 , and 2.34 W m^-2 ), setting a record of the output voltage among halide-perovskite-based nanogenerators. The LPPS-NFC also exhibits excellent stretchability, waterproofness, and breathability, enabling the fabrication of robust wearable devices that convert mechanical energy from different biomechanical motions into electrical power to drive common electronic devices. The LPPS-NFC-based energy harvesters also endure extreme mechanical deformations (washing, folding, and crumpling) without performance degradation, and maintain stable electrical output up to 5 months, demonstrating their promising potential for use as smart textiles and wearable power sources.

Refluxed Esterification of Fullerene-Conjugated P25 TiO2 Promotes Free Radical Scavenging Capacity and Facilitates Antiaging Potentials in Human Cells

Titanium dioxide nanomaterials have good capability to prevent human cells from damage under UV irradiation. However, some studies indicated that the nanoscale of titanium dioxide could potentially cause harmful effects such as free radical generation under UV irradiation and thereby accelerate the progress of cell aging. Fullerenes can scavenge large amounts of free radicals due to the fact that fullerenes contain enormous amount of π electrons with low lying lowest unoccupied molecular orbital, but its adverse properties, such as the poor solubility in water, restricted the applicability. In this study, we employed water-soluble carboxylic acid fullerenes (C₆₀-COOH and C₇₀-COOH) as the free radical scavenger and modify onto the surface of titanium dioxide by refluxed esterification (P25/C₆₀-COOH or C₇₀-COOH) technique. The conformation and properties of these nanomaterials were characterized by techniques and equipment such as X-ray diffraction, energy dispersive spectroscopy analysis, scanning electron microscopy, thermal gravimetric analysis, high-resolution transmission electron microscopy, and Fourier transform infrared spectroscopy. We also introduced methylene blue and rhodamine B as indicators to evaluate and demonstrate the scavenging capacity of these nanomaterials. Moreover, we examined the biocompatibility and UV protection capacity of our P25/fullerene composites in human 293T cells, and applied luciferase activity assay to investigate the possible underlying cell protection mechanisms exhibited by these nanomaterials. Our data indicate that both P25/C₆₀-COOH and P25/C₇₀-COOH could protect human cells against UV exposure. P25/C₇₀-COOH exhibits great anti-inflammation capacity, whereas P25/C₆₀-COOH exhibits great anti-oxidative stress and anti-DNA damage capacity. Our results suggest that most of our P25/fullerene composite materials have the ability to reduce free radicals and exhibit high biomedical potential in anti-inflammation, anti-oxidant, and anti-aging applications.

Role of Pristine and Acid-Functionalized Fullerene on Breaking Dye Aggregates and its Impact on the Efficiency of Solar Cells

Porphyrin dyes have an inherent tendency to aggregate. This leads to a self-quenching phenomenon that hinders electron transfer to the conduction band of semiconductors in dye-sensitized solar cells. Self-quenching adversely affects the efficiency of solar cells. Here, we report the interaction of porphyrin with pristine and acid-functionalized fullerene molecules on the surface of ZnO nanoparticles under chemisorbed conditions. Chemisorption of porphyrin only on ZnO nanoparticles instigates aggregation of the porphyrin molecules. These aggregates can be effectively broken by chemisorbing fullerene molecules on the surface of the ZnO nanoparticles. This is due to self-assembly formation processes because of porphyrin–fullerene interactions. The nanohybrid material, consisting of ZnO nanorods, acid-functionalized porphyrin, and fullerene derivatives, was characterized by UV–visible spectroscopy, fourier transform infrared spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. The material generates better performing dye-sensitized solar cells when compared with those fabricated from porphyrin-based photo-active material.