Precision Synthesis And Performance Study Of Non-planar Condensed Aromatic Hydrocarbon

Non-planar polycyclic aromatic hydrocarbons have unique electronic and optical properties as well as self-assembling behavior,attracting materials scientists with their peculiar structural and chemical properties.Due to their low susceptibility to self-aggregation,good solubility,and stability,they are easy to be subsequently processed for use in electronic devices,and have a unique potential for applications in fields such as energy storage devices,organic solar cells,and magnetics.The study of the conformational relationship between the structure and properties of non-planar thickened aromatic hydrocarbons is essential to broaden their application fields and improve their practical applications.This thesis focuses on the applications of non-planar polycyclic aromatic hydrocarbons in lithium-ion storage,organic solar cells,and magnetic properties,etc.The three-dimensional configuration and spatial arrangement structure of the molecules are accurately regulated by means of organic synthesis to improve their performance in the corresponding application scenarios.The main research content and innovations of this thesis are summarized as follows:（1）Long lithium-ion transport paths and slow insertion processes are the main challenges for lithium-ion battery anode materials for fast charging and low-temperature operation.In this chapter,c-HBC-8O molecules with twisted structures were synthesized,and the self-assembly of c-HBC-8O into a hierarchical supramolecular structure with"herringbone"-filled motifs was achieved through the interactions of C-H...πand hydrogen bonds.Due to the formation of ordered three-dimensional lithium-ion transport channels,the lithium-ion diffusion coefficient of c-HBC-8O is as high as 4.1×10^-8 cm² s^-1,which is an order of magnitude higher than that of previously reported organic anode materials for lithium-ion batteries.As a proof-of-concept,c-HBC-8O anode delivered outstanding fast-charging ability,high capacity and durable cycle stability of 298.3 m Ah g^-1 at 5 A g^-1 after 3000 cycles（25℃）,and320 m Ah g^-1 at 200 m A g^-1 after 1000 cycles even at low temperature（-20℃）.The present strategy opens up new approaches in the design ofπ-conjugated anode materials for lithium-ion batteries based on weak C-H…πinteractions.（2）Although fullerene derivatives such as[6,6]-phenyl-C₆₁/C₇₁-butyric acid methyl ester(PC₆₁BM/PC₇₁BM)have dominated the n-type materials as the photoactive acceptors in bulk heterojunction organic solar cells（OSCs）and the electron transporting materials（ETMs）in inverted perovskite solar cells（PVSCs）,they have several drawbacks such as weak absorption,limited structural tunability,prone to aggregation,and high costs of production.Constructing non-fullerene small molecules with three-dimensional（3D）molecular geometry is one of the strategies to replace fullerenes in both OSCs and PSCs.In this study,a 3D molecule,contorted hexa-cata-hexabenzocoronene tetra perylene diimide（HBC-4-PDI）,was designed and synthesized.HBC-4-PDI shows a wide and strong light absorption in the whole UV-vis region and suitable energy levels as an acceptor for OSCs and ETM for PVSCs.More importantly,the 3D construction effectively reduced the self-aggregation of c-HBC,leading to an appropriate scale phase separation of the blend film morphology in OSCs.A preliminary power conversion efficiency（PCE）of 2.70%with a champion open-circuit voltage of 1.06 V was obtained in OSCs with HBC-4-PDI as the acceptor,which was the highest among the previously reported OSCs based on c-HBC derivatives.Meanwhile,a promising PCE of 8.34%was also achieved in PVSCs when HBC-4-PDI was used as the ETM.The results indicated that HBC-4-PDI may serve as a good candidate to replace the fullerene derivatives.（3）Chichibabin’s hydrocarbons are polycyclic aromatic hydrocarbons with open-shell properties,and their related derivatives have been shown to possess remarkable two-radical properties as well as unique optical,electronic,and magnetic properties.However,the high reactivity of the radicals is a great challenge for their stabilization in the air environment,and previous studies have demonstrated that extending theπ-conjugated structure of Chichibabin’s hydrocarbons as well as increasing the spatial site resistance of the radical carbons is an effective strategy for the synthesis of stable open-shell Chichibabin’s hydrocarbons.In this dissertation study,the twisted structure,π-conjugate extension,andπ-conjugate blocking of a class of molecules of naphtholates Chichibabin’s hydrocarbons were precisely tuned by means of organic synthesis,and nine molecules of Chichibabin’s hydrocarbons derivatives with similar structures were prepared and tested for their radical properties to investigate the structural micro-modulation of the molecules’shell-opening properties.