Corannulene derivatives for organic electronics:From molecular engineering to applications

This paper intends to provide an overview for using corannulene derivatives in organic electronics such as organic field-effect transistors（OFETs）,organic solar cells（OSCs）,and organic light-emitting diodes（OLEDs）.We highlight the rational design strategies,tuning molecular orbital energy levels and arrangement in single crystals of corannulenes.The topological structure and properties of corannulene make it a unique candidate for organic electronics.

Building 2D quasicrystals from 5-fold symmetric corannulene molecules

The formation of long-range ordered aperiodic molecular films on quasicrystalline substrates is a new challenge that provides an opportunity for further surface functionalization. This aim can be realized through the smart selection of molecular building blocks, based on symmetry-matching between the underlying quasicrystal and individual molecules. It was previously found that the geometric registry between the C60 molecules and the 5- and 10-fold surfaces was key to the growth of quasiperiodic organic layers. However, an attempt to form a quasiperiodic C60 network on i-Ag-In-Yb substrates was unsuccessful, resulting in disordered molecular films. Here we report the growth of 5-fold symmetric corannulene C20H10 molecules on the 5-fold surfaces of i-Ag-In-Yb quasicrystals. Low-energy electron diffraction （LEED） and scanning tunneling microscopy （STM） revealed long-range quasiperiodic order and 5-fold rotational symmetry in self-assembled corannulene films. Recurrent decagonal molecular rings were seen, resulting from the decoration of specific adsorption sites with local pentagonal symmetry by corannulenes, adsorbed with their bowl-openings pointing away from the surface. They were identified as （Ag, In）-containing rhombic triacontahedral （RTH） duster centers and pentagonal Yb motifs, which cannot be occupied simultaneously due to steric hindrance. It is proposed that symmetry-matching between the molecule and specific substrate sites drives this organization. Alteration of the molecular rim by the introduction of CH substituents appeared to increase molecule mobility on the potential energy surface and facilitate trapping at these specific sites. This finding suggests that rational selection of molecular moiety enables the templated self-assembly of molecules leading to an ordered aperiodic corannulene layer.

Columnar Liquid Crystalline Corannulenes: Synthesis, Assembly and Charge-Carrier Transport Properties

Two discotic liquid crystalline(LC)molecules consisting of a bowl-shaped corannulene core and five-fold photoactive azobenzene branches with differe nt pa raff i nk side chai ns were developed.Their self-assembly,photo-resp on sive behavior and charge-carrier tran sport properties were investigated in detail.A wider mesophase temperature range was achieved when utilizi ng Ion ger and furcal flexible side chai n substituti on.2D XRD measureme nts revealed the n-packed cora nnulen e-ce ntered lb(i.e.,with furcal side alkoxy I chains)exhibited helical columnar LC phase.This packing structure also led to a higher hole charge carrier mobility of 7.07 ×1O^(-2) cm^(2)-V^(-1)s^(-1) compared to that of the counterpart la with linear side chain substitutions.

Carbon-based materials for photodynamic therapy: A mini-review

Carbon-based materials have been extensively applied in photodynamic therapy owing to the unique optical characteristics,good biocompatibility and tunable systematic toxicity.This mini-review mainly focuses on the recent application of carbon-based materials including graphene,carbon nanotube,fullerene,corannulene,carbon dot and mesoporous carbon nanoparticle.The carbon-based materials can perform not only as photosensitizers,but also effective carriers for photosensitizers in photodynamic therapy,and its combined treatment.