Fullerene Hybrid Research Articles

Electronic Coupling Between Perovskite Nanocrystal and Fullerene Modulates Hot Carrier Capture

AbstractThe efficient harnessing of hot carriers holds transformative potential for next‐generation optoelectronic devices. Halide perovskites, with their remarkably long carrier lifetimes exceeding 10 picoseconds, stand at the forefront of this research frontier. Yet, a fundamental paradox persists: why does efficient hot carrier capture remain elusive despite these extended lifetimes? Here, this conundrum is unraveled by constructing a donor–acceptor model system: perovskite nanocrystal and fullerene hybrids. It is demonstrated that the challenge lies not only in the carrier lifetime itself but in the nature of the coupling between donor and acceptor components. Remarkably, it is discovered that the formation of ground‐state complexes, with effective coupling across a wide energy range, not only overcomes the initially forbidden hot carrier capture within these hybrids but also dramatically enhances it, achieving a ≈76% hot carrier capture efficiency. This finding shifts the paradigm of hot carrier capture from extending carrier lifetimes to engineering donor–acceptor coupling, illuminating a path toward practical hot carrier applications.

Room temperature excitonic coupling in self-assembled copper – Fullerene hybrid films exposed to ambient air

Analytically sound combination of organic and inorganic semiconductors in designing functional hybrid nanomaterials promises new advances in nanoscience and in creation of next-generation optoelectronic devices. In this work, we report on combining two contrasting semiconductors (inorganic and organic) possessing attractive optical and electronic properties, namely Cu2O (in form of small single-crystalline nanoparticles, NPs) and C60-fullerene (as a medium supporting the NP ensemble), which were formed within the well-controlled Cux(Oy)C60 hybrid films through self-assembling and ambient air exposure of the vapour-deposited Cu and C60 mixture. The controllability of the hybrid film nanostructure was established and verified through systematic study of the films using Rutherford backscattering spectrometry, transmission electron microscopy, X-ray diffraction, Raman spectrometry and spectroscopic ellipsometry. The remarkable coincidence of the optical absorption peaks around 3.5 eV, reported for the Wannier-Mott (WM) excitons in a Cu2O crystal and detected for the Frenkel (F) excitons in the pristine C60 film, allowed us to observe room temperature polaritons as a product of the F-WM excitonic strong coupling. Quite high coupling energy of the FWM hybrid exciton estimated for the Cux(Oy)C60 films in the x interval of 5 < x < 15 (from 390 meV to 610 meV) implies the mediated effect of nanocavity photons and quantum confinement effect, strongly enhancing the hybrid exciton coupling energy. The implemented study discloses the self-assembled Cux(Oy)C60 hybrid films as promising material for application in optoelectronics and nonlinear optics.

Synthesis of inter-[60]fullerene conjugates with inherent chirality

Coalescence of [60]fullerenes potentially produces hypothetical nanocarbon assemblies with non-naturally occurring topologies. Since the discovery of [60]fullerene in 1985, coalesced [60]fullerene oligomers have only been observed as transient species by transmission electron microscopy during an oligomerization process under a high electron acceleration voltage. Herein, we showcase the rational synthesis of covalent assemblies consisting of inherently chiral open-[60]fullerenes. The crystallographic analyses unveiled double-caged structures of non-conjugated and conjugated inter-[60]fullerene hybrids, in which the two [60]fullerene cages are bounds to each other through a covalent linkage. The former one further assembles via a heterochiral recognition so that four carbon cages are arranged in a tetrahedral manner both in solution and solid state. Reflecting radially-conjugated double π-surface nature, the inter-[60]fullerene conjugate exhibits strong electronic communication in its reduced states, intense absorption behavior, and chiroptical activity with a dissymmetry factor of 0.21 (at 674 nm) which breaks the record for known chiral organic molecules.

Hybrid Steroid‐[60]Fullerene as n‐Type Material for Organic Photovoltaics

AbstractFullerene derivatives have been used as electron acceptor and transport materials in organic photovoltaics as well as in perovskite solar cells. Among them, [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) has been one of the most widely used, in combination with poly‐3‐hexylthiophene (P3HT) as an electron donor semiconducting polymer, for the fabrication of organic bulk heterojunction solar cells (BHJ‐OSC). In this work, a steroid‐fullerene hybrid was synthesized through the Bingel–Hirsch reaction to compare its properties with PC61BM as the reference structure. Different spectroscopic techniques were employed to characterize the new fullerene derivative, namely 1D and 2D nuclear magnetic resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and high‐resolution mass spectrometry (HRMS). In addition, thermogravimetric analysis (TGA), and cyclic voltammetry were also performed. The characterization was completed by transmission electron microscopy (TEM), which explore the hybrid‘s morphology, where the presence of the steroid moiety increases the solubility of the fullerene material. DFT/PBE−D3(BJ)/6‐311G(d,p) calculations for both the steroid‐fullerene hybrid and PC61BM allowed to obtain geometry optimizations and electronic structure data. A comparative study to analyze the nature of the electronic properties of the synthesized steroid‐[60]fullerene hybrid and PC61BM with an oligomer of ten thiophene units, used in the active layer of organic solar cells, was carried out. Electron density maps using the [CIS|CNDOL/21] approach illustrate the photoexcitation of the donor followed by an electron‐charge transfer to the acceptor fullerene.

Synthesis of C&lt;sub&gt;60&lt;/sub&gt; fullerene hybrid molecules with catecholamines under the action of ultrasound

For the first time, morpholine monoadducts of С60-fullerene were obtained in the reactions of fullerene with biogenic amines (norepinephrine, adrenaline) under the action of ultrasound. The reactions take place in air in ( g 2.0000 and Δ H 1/2 3.2 G) was detected by EPR, a key intermediate in the synthesis of the C60-adrenaline cycloadduct, which was obtained as a result •-a toluene/DMF medium at room temperature. The radical anion C60- of a one-electron transition from the adrenaline molecule to the C60 framework.

Synthesis of [60]Fullerene Hybrids Endowed with Steroids and Monosaccharides: Theoretical Underpinning as Promising anti-SARS-CoV-2 Agents.

Cyclopropanation reactions between C60 and different malonates decorated with monosaccharides and steroids using the Bingel-Hirsch methodology have allowed the obtention of a new family of hybrid compounds in good yields. A complete set of instrumental techniques has allowed us to fully characterize the hybrid derivatives and to determine the chemical structure of monocycloadducts. Besides, the proposed structures were investigated by cyclic voltammetry, which evidenced the exclusive reductive pattern of fullerene Bingel-type monoadducts. Theoretical calculations at the DFT-D3(BJ)/PBE 6-311G(d,p) level of the synthesized conjugates predict the most stable conformation and determine the factors that control the hybrid molecules' geometry. Some parameters such as polarity, lipophilicity, polar surface area, hydrophilicity index, and solvent-accessible surface area were also estimated, predicting its potential permeability and capability as cell membrane penetrators. Additionally, a molecular docking simulation has been carried out using the main protease of SARS-CoV-2 (Mpro) as the receptor, thus paving the way to study the potential application of these hybrids in biomedicine.

Photoswitchable Phosphonate-Fullerene Hybrids with Cholinesterase Activity.

Modern progress in photopharmocology calls for new generation of compounds joining bioactivity, photoswitchable properties and high selectivity of response to light wavelength. Introduced here, phosphonate-fullerene hybrids are the first representatives of such compounds. Phosphonate-fullerene hybrids were synthesized on a base of fullerene C60 and organophosphates with the function of photoswitchable cholinesterase activity-phosphorylated thiazolotriazole and aminomalonate compounds and studied with FTIR, UV-VIS spectroscopy and IPC-micro neurotoxin amperometric analysis. As a result of spectroscopic and bioactivity characterization, it was not only demonstrated butyrylcholinesterase (BuChE) inhibition increase in phosphonate-fullerene hybrids compared with pure phosphonates but also pronounced response of inhibition degree to laser irradiation of hybrids. It was found opposite behavior of hybrids as a result of laser irradiation-BuChE inhibition drop-off for thiazolotriazole-fullerene and pronounced growth for aminomalonate-fullerene. The other remarkable peculiarity of presented phosphonate-fullerene hybrids is high selectivity of inhibition change degree to laser wavelength (266 or 325 nm).

A 3D Peptide/[60]Fullerene Hybrid for Multivalent Recognition.

Fully substituted peptide/[60]fullerene hexakis-adducts offer an excellent opportunity for multivalent protein recognition. In contrast to monofunctionalized fullerene hybrids, peptide/[60]fullerene hexakis-adducts display multiple copies of a peptide in close spatial proximity and in the three dimensions of space. High affinity peptide binders for almost any target can be currently identified by in vitro evolution techniques, often providing synthetically simpler alternatives to natural ligands. However, despite the potential of peptide/[60]fullerene hexakis-adducts, these promising conjugates have not been reported to date. Here we present a synthetic strategy for the construction of 3D multivalent hybrids that are able to bind with high affinity the E-selectin. The here synthesized fully substituted peptide/[60]fullerene hybrids and their multivalent recognition of natural receptors constitute a proof of principle for their future application as functional biocompatible materials.

A 3D Peptide/[60]Fullerene Hybrid for Multivalent Recognition

AbstractFully substituted peptide/[60]fullerene hexakis‐adducts offer an excellent opportunity for multivalent protein recognition. In contrast to monofunctionalized fullerene hybrids, peptide/[60]fullerene hexakis‐adducts display multiple copies of a peptide in close spatial proximity and in the three dimensions of space. High affinity peptide binders for almost any target can be currently identified by in vitro evolution techniques, often providing synthetically simpler alternatives to natural ligands. However, despite the potential of peptide/[60]fullerene hexakis‐adducts, these promising conjugates have not been reported to date. Here we present a synthetic strategy for the construction of 3D multivalent hybrids that are able to bind with high affinity the E‐selectin. The here synthesized fully substituted peptide/[60]fullerene hybrids and their multivalent recognition of natural receptors constitute a proof of principle for their future application as functional biocompatible materials.

Fabrication and Molecular Modeling of Navette-Shaped Fullerene Nanorods Using Tobacco Mosaic Virus as a Nanotemplate.

To date, metallization studies have been performed with the nanometer-scale template, Tobacco Mosaic Virus (TMV). Here we show that fullerenes as well can be deposited on TMV coat protein in a controlled manner. Two methods were followed for the coating process. First, underivatized fullerene was dispersed in different solvents to bring the underivatized fullerene and wild-type TMV together. Improved depositions were obtained with the fullerene dicarboxylic derivative synthesized via the Bingel method. The form of the coating was analyzed by transmission electron microscopy. Our results demonstrate that the coating efficiency with the carboxy derivative was much better compared to the underivatized fullerene. The goal of coupling a carbon nanoparticle to a biological molecule, the viral coat of TMV, was achieved with the carboxy derivative of fullerene, resulting in the production of navette-shaped nanorods. The interactions between carboxyfullerenes and TMV were investigated through modeling with computational simulations and Gaussian-based density functional theory (DFT) calculations using the Gaussian09 program package. The theoretical calculations supported the experimental findings. This inexpensive and untroublesome method promises new fullerene hybrid nanomaterials in particular shapes and structures.

Electrocatalytic activity for proton reduction by a covalent non-metal graphene-fullerene hybrid.

A non-metal covalent hybrid of fullerene and graphene was synthesized in one step via fluorographene chemistry. Its electrocatalytic performance for the hydrogen evolution reaction and durability was ascribed to intrahybrid charge-transfer phenomena, exploiting the electron-accepting properties of C60 and the high conductivity and large surface area of graphene.

Chitosan and fullerene hybrid hydrogel for drug delivery system with enhanced antitumor cell effects

Fullerene is a spherical hollow structure composed of carbon atoms. It has emerged in the new development of numerous fullerene-based compounds with a variety of biological targets such as anticancer, cytoprotection, tissue regeneration, and controlled drug delivery. Because of its biodegradable property of chitosan hydrogels, fullerine can function as a drug delivery system for implants with optimal degradation profiles that result in the proper rates of drug release. In this study, a chitosan-fullerene hybrid hydrogel was fabricated, and chemical and biological tests were performed to characterize it. We have shown that the incorpration of fullerene into the hydrogel decreased the degradation and swelling rate of the hydrogel. A rheology test showed that the addition of fullerene increased the elastic modulus of the hydrogel. Chitosan hydrogel containing fullerene reduced the releasing rate of methotrexate (MTX) loaded in the hydrogel. A cell viability assay showed that fullerene in the hydrogel was not toxic to the cultured cells. The fullerene in the chitosan hydrogel significantly enhanced the anti-tumor cell effect. This study implies that the combined application of fullerene and chitosan hydrogel is a promising strategy for drug delivery in tumor therapy.

Tunable Photoswitching in Norbornadiene (NBD)/Quadricyclane (QC) - Fullerene Hybrids.

With respect to molecular switches, initializing the quadricyclane (QC) to norbornadiene (NBD) back‐reaction by light is highly desirable. Our previous publication provided a unique solution for this purpose by utilizing covalently bound C60. In this work, the fundamental processes within these hybrids has been investigated. Variation of the linker unit connecting the NBD/QC moiety with the fullerene core is used as a tool to tune the properties of the resulting hybrids. Utilizing the Prato reaction, two unprecedented NBD/QC – fullerene hybrids having a long‐rigid and a short‐rigid linker were synthesized. Molecular dynamics simulations revealed that this results in an average QC–C60 distance of up to 14.2 Å. By comparing the NBD–QC switching of these derivatives with the already established one having a flexible linker, valuable mechanistic insights were gained. Most importantly, spatial convergence of the QC moiety and the fullerene core is inevitable for an efficient back‐reaction.

(Invited) Endohedral Fullerene Hybrids: From Gold Nanoparticles to Graphene

Endohedral fullerenes are at the forefront of nanotechnology due to their rich electronic structure. In this talk I will focus on some examples of endohedral fullerenes used in hybrid nanostructures with other nanomaterials. For example, gold nanoparticles have been found to significantly increase or alternatively quench the photoluminescence of dyes, enhance the Raman scattering of organic molecules and the photocatalytic activity of semiconductors. We have reported for the first time the use of the singlet oxygen sensor green for the evaluation of the generation of singlet oxygen from a series of fullerenes (including endohedral fullerenes) and gold nanoparticle hybrids. The C70 mono adducts appear to be more efficient sensitizers compared to C60 in accordance with previous studies that were based on the 1270 nm emission of the singlet oxygen. Lu3N@C80 had a performance somewhat between the two empty cages. Overall, pyrene derivatives appeared to be efficient photo-sensitizers, especially when coupled with gold nanoparticles, with the 2.24 and 3.48 times increase on the fluorescence intensity.I will also elaborate on how Gd-based metallofullerene (Gd3N@C80) molecules can be used to create single adatoms and nanoclusters on a graphene surface. We have shown that endohedral metallofullerenes can adhere to graphene surfaces at temperatures well above their bulk sublimation point, indicating that the surface bound metallofullerenes have strong adhesion to dangling bonds on graphene surfaces. The ability to create dispersed single Gd adatoms, and Gd nanoclusters on graphene may have impact in spintronics and magnetism.Endohedral metallofullerenes continue to fascinate us with their versatility and attractive electronic properties.

Cover Feature: [60]Fullerene Hybrids Bearing “Steroid Wings”: A Joined Experimental and Theoretical Investigation (Eur. J. Org. Chem. 37/2020)

Cover Feature: [60]Fullerene Hybrids Bearing “Steroid Wings”: A Joined Experimental and Theoretical Investigation (Eur. J. Org. Chem. 37/2020)

60]Fullerene Hybrids Bearing “Steroid Wings”: A Joined Experimental and Theoretical Investigation

Novel [60]fullerene‐steroid hybrids have been synthesized by Bingel–Hirsch cyclopropanation reaction between C60 and steroid malonates, leading to conjugates in which a [60]fullerene unit is connected to one or two dehydroepiandrosterone moieties, an important naturally occurring steroid hormone. The obtained derivatives have been fully characterized by a whole set of instrumental techniques in order to determine their chemical structure. Moreover, their electrochemical properties, investigated by cyclic voltammetry, revealed the presence of three reversible reduction waves for both hybrids. Furthermore, Transmission Electron Microscopy studies allowed to determine the morphology and size of the fullerene hybrids in aqueous solution, showing a tendency to organize into spherical nanoscale structures. Theoretical calculations using the DFT‐PBE method and 6‐311G(d,p) basis set, were performed to predict the most stable conformations for the synthesized compounds, and to determine the factors that control the geometry of these hybrid molecules. In addition, parameters such as polarity, and lipophilicity were estimated. The obtained results corroborate the predicted activity against HIV‐1 protease as suggested by molecular docking simulation.

Visible-light driven photodegradation on Ag nanoparticle-embedded fullerene (C60) heterostructural microcubes

Three-dimensional Ag(I)-fullerene hybrid microcrystal is fabricated by AgNO3 assisted liquid-liquid interfacial precipitation, containing the abundant sp2-π-electron system. With a mild chemical reduction, it produces the massive Ag nanocluster/fullerene junctions, on which fullerene doubles role as the excellent electron acceptor and photon scavenger, enabling the Plasmon-driven catalytic reaction. Ag nanocluster employed alone could not perform this photocatalytic reaction, neither of fullerene (C60) crystal. It implicates that Ag-fullerene interface is a key to drive catalytic process. Relative to conventional TiO2 nanostructures, fullerene expands light absorption to most solar wavelength and possesses a tightened bandgap which intrinsically expedites the charge transfer and charge separation from coinage metals. Demonstrated by photodegradation of organic molecules, this Ag(I)-fullerene (C60) composite, consisted of a plethora of electron donor-acceptor dyads renders an additional member to photocatalyst family, potentially implemented for photo-electron conversion, water remedy and beyond.

Photoemission from hybrid states of Cl@C60 before and after a stabilizing charge transfer

Photoionization calculations of the endofullerene molecule Cl@C60 with an open-shell chlorine atom are performed in the linear response density functional theory based on a spherical jellium model of C60. Cross sections for atom–fullerene hybrid photoemission studied show the effects of the hybridization symmetry, the giant plasmon and the molecular cavity. Comparisons with the results of Ar@C60 provide insights into the role of a shell-closing electron and its influence on the dynamics. The results for Cl@C60 are further compared with those of a more stable configuration that results after a C60 electron transfers to Cl forming Cl−@. This comparison reveals noticeable differences in the ionization properties of the antibonding hybrid state while the bonding hybrid remains nearly unaltered showing a magnification covering the entire giant plasmon energy range. These predictions should raise interest in probing the molecular configuration using photoelectron spectroscopy.

Raman Spectroscopy of AgNO3 Complex Encapsulated Fullerene (C60) Microcube

Ag+-fullerene (C60) hybrid microcrystal is synthesized by a liquid-liquid interfacial precipitation, which shows the broadened and weakened Raman bands, relative to original C60 monomers. Our experimental results, combined with numerical calculation implicate that charge transfer and overlap orbitals between Ag+ and C60 steered this dramatic change of Raman response, due to greatly reduced molecular symmetry and redistributed electron density. Density functional theory (DFT) calculations rationalize the degenerated Raman spectra of Ag+-exohedral fullerene conjugate through ƞ1 (C1-top) and ƞ2 (C2-bridge) sites, elucidating that the binding nature (π-5 s and d-π*) shifts partially from electrostatic to covalent bond. This study is expected to render a general and easily accessible Raman approach in deciphering transition metal ion-fullerene interactions.

(Invited) Endohedral Fullerene Hybrids: From Gold Nanoparticles to Graphene

Endohedral fullerenes are at the forefront of nanotechnology due to their rich electronic structure. In this talk I will focus on some examples of endohedral fullerenes used in hybrid nanostructures with other nanomaterials. For example, gold nanoparticles have been found to significantly increase or alternatively quench the photoluminescence of dyes, enhance the Raman scattering of organic molecules and the photocatalytic activity of semiconductors. We have reported for the first time the use of the singlet oxygen sensor green for the evaluation of the generation of singlet oxygen from a series of fullerenes (including endohedral fullerenes) and gold nanoparticle hybrids. The C70 mono adducts appear to be more efficient sensitizers compared to C60 in accordance with previous studies that were based on the 1270 nm emission of the singlet oxygen. Lu3N@C80 had a performance somewhat between the two empty cages. Overall, pyrene derivatives appeared to be efficient photo-sensitizers, especially when coupled with gold nanoparticles, with the 2.24 and 3.48 times increase on the fluorescence intensity.I will also elaborate on how Gd-based metallofullerene (Gd3N@C80) molecules can be used to create single adatoms and nanoclusters on a graphene surface. We have shown that endohedral metallofullerenes can adhere to graphene surfaces at temperatures well above their bulk sublimation point, indicating that the surface bound metallofullerenes have strong adhesion to dangling bonds on graphene surfaces. The ability to create dispersed single Gd adatoms, and Gd nanoclusters on graphene may have impact in spintronics and magnetism.Endohedral metallofullerenes continue to fascinate us with their versatility and attractive electronic properties.