Electrochemical and electronic properties of nitrogen doped fullerene and its derivatives for lithium-ion battery applications

We have studied the redox potentials and electronic properties of C60 and C59N using density functional theory method. It is found that doping C60 with one nitrogen atom results in a slight increase in redox potential. Next, we have also studied C59N functionalized with various redox-active oxygen containing functional groups and strongly electron withdrawing functional groups. It is found that the intrinsic electronic structure of the molecule is the major determinant of the redox potential. Our DFT calculations show that the electron affinity to redox potential of functionalized C59N is correlated with the LUMO of the systems very well. This is the first systematic study on the redox properties and electronic structures of N-doped C60 systems.

Dual-light emitting 3D encryption with printable fluorescent-phosphorescent metal-organic frameworks

Optical encryption technologies based on room-temperature light-emitting materials are of considerable interest.Herein,we present three-dimensional(3D)printable dual-light-emitting materials for high-performance optical pattern encryption.These are based on fluorescent perovskite nanocrystals(NCs)embedded in metal-organic frameworks(MOFs)designed for phosphorescent host-guest interactions.Notably,perovskite-containing MOFs emit a highly efficient blue phosphorescence,and perovskite NCs embedded in the MOFs emit characteristic green or red fluorescence under ultraviolet(UV)irradiation.Such dual-light-emitting MOFs with independent fluorescence and phosphorescence emissions are employed in pochoir pattern encryption,wherein actual information with transient phosphorescence is efficiently concealed behind fake information with fluorescence under UV exposure.Moreover,a 3D cubic skeleton is developed with the dual-light-emitting MOF powder dispersed in 3D-printable polymer filaments for 3D dual-pattern encryption.This article outlines a universal principle for developing MOF-based room-temperature multi-light-emitting materials and a strategy for multidimensional information encryption with enhanced capacity and security.

Covalent organic frameworks:Design and applications in electrochemical energy storage devices

As an emerging class of crystalline organic material,covalent organic frameworks(COFs)possess uniform porosity,versatile functionality,and precise control over designated structures.Aside from the favorable charge and mass transport pathways offered by the porous framework,COFs can also exhibit designed reversible redox activity.In the past few years,their potential has attracted a great deal of attention for charge storage and transport applications in various electrochemical energy storage devices,and numerous design strategies have been proposed to enhance the corresponding electrochemical properties.This review summarizes the working principle and synthesis methods of COFs and discusses significant findings for supercapacitors and various rechargeable battery systems,emphasizing the representative design strategies and their underlying relationship with electrochemical performances.In addition,key advances achieved by computations are highlighted along with the challenges and prospects in this field.