Xiaohong Cheng

Benzodithiophene‐based bolaamphiphiles 1 and 2 , differing only in the length of the rigid core, can self‐assemble into two distinct highly coordinated cubic liquid crystalline phases through a delicate balance of molecular geometry and optimized packing. Shorter core compound 1 forms a single 6‐connected primitive cubic network (SP, Pm m ), while longer core compound 2 stabilizes an 8‐connected body‐centered cubic network (BCC, Im m ), representing an exceptionally high coordination number of junctions achieved via thermodynamic control. Notably, despite its achiral molecular design, compound 1 also exhibits spontaneous symmetry breaking in the gel state formed in polar solvents. Here, it organizes into chiral helical nanoribbons through a columnar hexagonal packing mode driven by directional π‐π stacking, which is distinct from the thermotropic cubic liquid crystalline phases formed in bulk. Furthermore, these bolaamphiphiles were incorporated as dopants into the hole transport layers of perovskite solar cells. As a result, the devices exhibit enhanced charge transport, reduced interfacial defects, and improved energy level alignment, achieving a power conversion efficiency of 23.88% and retaining more than 90% of initial performance over 1500 h. This work provides fundamental insights into the design of soft matter with programmable nanoarchitectures and demonstrates their potential for high‐performance optoelectronics.

A series of bow-shaped hexacatenar molecules based on a diphenylamine core are reported.

4,6-Diamino-1,3,5-triazine (DT) derivatives typically exhibit excellent liquid crystal properties, attracting numerous researchers interested in enhancing their performance. In this paper, two DT molecules (DT−10 and DT−12) are employed to elucidate the effects of their backbone length and number of branches in the tail chains on self-assembled nanostructures using scanning tunneling microscopy (STM) at the 1-octanoic acid/highly ordered pyrolytic graphite interface, compared to our previous report (2TDT−n, n = 10,12,16,18). DT−10 features a short backbone and a trialkoxy chain tail, whereas DT−12 possesses a long backbone and bifurcated chain tails. STM results reveal that DT−10 assembles into a cross-shaped nanostructure with DT head groups arranged in a head-to-head configuration stabilized by a pair of N–H···N hydrogen bindings (HBs). In contrast, DT−12 assembles into a two-row linear pattern, where DT head groups exhibit a side-by-side arrangement mediated by a pair of N–H···N HBs. Comparison with our previous findings indicates that although variations in backbone length and tail chain branching can modulate the nanostructural features of DT derivatives, the chain length of DT molecules emerges as a pivotal factor governing their assembly architecture.

Diaminetriazine (DT) derivatives typically exhibit excellent liquid crystal properties, attracting numerous researchers interested in enhancing their performance. In this paper, two DT molecules (DT−10 and DT−12) are used to investigate how their backbone length and number of branches in the tail chains influence self-assembled nanostructures using scanning tunnelling microscopy (STM) at the 1-octanoic acid/graphite interface, compared to our previous report (2TDT−n, n = 10,12,16,18). DT−10 has a short backbone and a trialkoxy chain tail and DT−12 has a long backbone and a bifurcated chain tail. The STM results demonstrate that DT−10 adopts a cross-shaped nanostructure design and the DT heads take a head-to-head fashion connected by a pair of N–H···N hydrogen bindings (HBs). DT−12 assembles into a two-row linear pattern and DT heads take a side by side fashion connected by a pair of N–H···N HBs. After comparing with the results we previously reported, it is demonstrated that changes in the length of the backbone and the number of tail branches can only regulate the nanostructure of DT derivatives, however, the chain length of DT molecules is a key factor determining their assembly structure.

Polycatenar columnar liquid crystals nT (n = 1–6) of π-conjugated oligothiophenes end-capped with bulky N-tris(hexadecyloxy)benzyl carbazole groups exhibit unusual molecular tilted and parallel assemblies, realizing the reversal of birefringence within the columnar liquid crystalline (LC) phases depending on core length and temperature. In the parallel arrangement of short core compounds 2T and 3T, molecules align perpendicular to the column axis. The stacking of these molecules involves a rotational component, resulting in local helical assembly, and this specific packing motif collectively stabilizes the Col_hex/p6mm phase with negative birefringence. In the tilted arrangement of long core compounds 5T and 6T, the long rigid core-driven tilted assemblies induce a structural transition to the Col_rec/c2mm phase, accompanied by a characteristic reversal of birefringence from negative to positive. In particular, compound 4T forms a Col_hex/p6mm phase at lower temperature, but transforms into a Col_rec/c2mm phase at higher temperature, accompanied by an inversion of optical birefringence. These special LC nanostructures provide important insights into the correlation between the molecular structure and assembly orientation in π-conjugated oligothiophenes. Furthermore, with an increase in π-conjugation length, these compounds exhibit bright blue-to-red emission in both solution and thin-film states, covering the entire visible spectrum and enabling their use in the preparation of full-color light-emitting diodes (LEDs), including white light. Most interestingly, solution-processable nano-films derived from columnar polycatenar oligothiophenes exhibit excellent hole mobility. Thus, this work proposes a strategy to develop polycatenar LC semiconductors that exhibit full-color emission.

Carbazole‐based bolaamphiphiles, featuring two thiophenes interconnected by a central carbazole as rigid core, decorated with three lateral chains and two sticky glycerol end groups, can exhibit complex self‐assembly structures of square honeycomb via smectic A to body‐centered cubic mesophase in bulk state and multiplex supramolecular organogels in solvent through alkyl chain engineering. The relevant self‐assembly mechanism has been elucidated based on polarizing optical microscopy, differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy measurements, as well as theoretical calculations. It is very interesting and fascinating to find that such carbazole‐based bolaamphiphiles can be integrated into the Spiro hole transport layer of perovskite solar cells, enhancing the photoelectric conversion efficiency to 23.39%.

Coumarin asymmetric multi‐chain liquid crystals (LCs) were synthesized using click reaction, with coumarin core and 1,2,3‐triazole dendritic wings on both sides. The properties of these LCs and the resulting gels were investigated using polarized optical microscopy (POM), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). These polycatenars demonstrate the ability to self‐assemble into columnar LCs phases, exhibiting p4 mm symmetry in their bulk states. In DMF solvent, ether compounds yield gels with notably more ordered, spherical flower‐like morphologies, while ester compounds produce gels that are less ordered and exhibit a nanosphere morphology. The findings indicate that the polarities of both the linkages and the solvents play a critical role in the formation of supramolecular nanostructures. Interestingly, the 2 was proved as promising imaging probe for latent fingerprints (LFPs) and fluorescent fingerprints images were obtained with high‐resolution, which showed potential practical application for LFPs detection. Additionally, LCs compounds are used as dopants to modify the poly(3,4‐ethylenedioxythiophene):polystyrene (PEDOT:PSS) injection layer of Organic silicone‐based heterojunction solar cells (HSCs). Finally, Density functional theory (DFT) calculations are performed to theoretically study such as geometric structure, frontier molecular orbitals, molecular electrostatic potential, and dipole moment.