Progress in Antiviral Fullerene Research.

Unlike traditional small molecule drugs, fullerene is an all-carbon nanomolecule with a spherical cage structure. Fullerene exhibits high levels of antiviral activity, inhibiting virus replication in vitro and in vivo. In this review, we systematically summarize the latest research regarding the different types of fullerenes investigated in antiviral studies. We discuss the unique structural advantage of fullerenes, present diverse modification strategies based on the addition of various functional groups, assess the effect of structural differences on antiviral activity, and describe the possible antiviral mechanism. Finally, we discuss the prospective development of fullerenes as antiviral drugs.

Tailoring Functional Terminals on Solution-Processable Fullerene Electron Transporting Materials for High Performance Perovskite Solar Cells.

Widely known as an excellent electron transporting material (ETM), pristine fullerene C60 plays a critical role in improving the photovoltaic performance of inverted structure perovskite solar cells (PSCs). However, the imperfect perovskite/C60 interface significantly limits the promotion of device performance and stability due to the weak coordination interactions between bare carbon cages and perovskite. Here, we designed and synthesized three functionalized fulleropyrrolidine ETMs (abbreviated as CEP, CEPE, and CECB), each of which was modified with the same primary terminal (cyanoethyl) and various secondary terminals (phenyl, phenethyl, and chlorobutyl). The resulting CECB-based PSC has a power conversion efficiency (PCE) over 19% and exceptional photo-stability over 1800 h. This work provides significant insight into the targeted terminal design of novel fullerene ETMs for efficient and stable PSCs.

Synthesis of Fullerenes from a Nonaromatic Chloroform through a Newly Developed Ultrahigh-Temperature Flash Vacuum Pyrolysis Apparatus.

The flash vacuum pyrolysis (FVP) technique is useful for preparing curved polycyclic aromatic compounds (PAHs) and caged nanocarbon molecules, such as the well-known corannulene and fullerene C60. However, the operating temperature of the traditional FVP apparatus is limited to ~1250 °C, which is not sufficient to overcome the high energy barriers of some reactions. Herein, we report an ultrahigh-temperature FVP (UT-FVP) apparatus with a controllable operating temperature of up to 2500 °C to synthesize fullerene C60 from a nonaromatic single carbon reactant, i.e., chloroform, at 1350 °C or above. Fullerene C60 cannot be obtained from CHCl3 using the traditional FVP apparatus because of the limitation of the reaction temperature. The significant improvements in the UT-FVP apparatus, compared to the traditional FVP apparatus, were the replacement of the quartz tube with a graphite tube and the direct heating of the graphite tube by impedance heating instead of indirect heating of the quartz tube using an electric furnace. Because of the higher temperature range, UT-FVP can not only synthesize fullerene C60 from single carbon nonaromatic reactants but sublimate some high-molecular-weight compounds to synthesize larger curved PAHs in the future.

Mixed Fullerene Electron Transport Layers with Fluorocarbon Chains Assembling on the Surface: A Moisture-Resistant Coverage for Perovskite Solar Cells.

In p-i-n structure perovskite solar cells (PSCs), the most prevalent electron transport layer (ETL), [6, 6]-phenyl-C61-butyric acid methyl ester (PC61BM), acts as both electron extractor and protective coverage to the underlayer perovskite. Notably, multifunctional mixed fullerene ETLs show great potential in further improving both the power conversion efficiency (PCE) and stability of PSCs compared to the single PC61BM ETL. In this work, we reported the mixed fullerene ETLs comprising of PC61BM and its two analogs with different length of fluorocarbon chains, [6, 6]-phenyl-C61-buryric acid 1H,1H-trifluoro-1-ethyl ester (abbreviated, CF3-PC61BM) and [6, 6]-phenyl-C61-buryric acid 1H, 1H-tridecafluoro-1-heptyl ester (abbreviated, C6F13-PC61BM). We obtained excellent PCEs of 18.37% and 17.71% for 1 wt % CF3-PC61BM- and C6F13-PC61BM-based PSCs (1 wt % addition of PC61BM) with CH3NH3PbI3 (MAPbI3) perovskites, respectively. Moreover, champion PCEs of ∼19% were obtained based on the CsFAMAPbIBr perovskites. Subsequent experiments demonstrated that the fluorocarbon chains of CF3-PC61BM and C6F13-PC61BM assembled at the surfaces of ETLs with the formation of thin-layer moisture-resistant protective coverage above perovskite. Results show that it significantly retarded water penetrating down to perovskite layers and led to optimal humidity stability under ambient atmosphere.

Rational synthesis of an atomically precise carboncone under mild conditions.

Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.