The interaction between organic photoelectric molecules leads to the formation of a certain aggregation structure, which plays a pivotal role in the charge transport at the intermolecular interface. In view of this, we investigated the mechanism and law of intermolecular interaction by detecting the self-assembled behaviors between organic photoelectric molecules at the interface by scanning tunneling microscopy (STM). In this work, the structural transformations of tetraphenylethylene acids (H₄ETTCs) on graphite surface induced by temperature and triazine derivatives (zcy-19, zcy-27, and zcy-38 molecules) were studied by STM technology and density functional theory (DFT) calculations. At room temperature, zcy-19 and H₄ETTC molecules formed a small range of ordered co-assembled nanostructure, while for zcy-27 or zcy-38 molecules, no co-assembled nanostructures were observed and only their own self-assembled structures existed on graphite surface, individually. In the thermal annealing trials, the original co-assembled H₄ETTC/zcy-19 structure disappeared, and only zcy-19 and H₄ETTC self-assembled in separate domains. Nevertheless, new well-ordered H₄ETTC/zcy-27 or H₄ETTC/zcy-38 co-assembled structures appeared at different annealing temperatures, respectively. Combined with DFT calculations, we further analyzed the mechanism of such structural transformations by triazine derivatives and temperature. Results reveal that triazine derivatives could interact with H₄ETTC by N–H···O and O–H···N hydrogen bondings, and whether temperature or zcy series compounds could achieve successful regulation of H₄ETTC assembly behavior is closely associated with the conjugated skeleton length of zcy series compounds.

Semitransparent organic solar cells show attractive potential in the application of building-integrated photovoltaics, agrivoltaics, floating photovoltaics, and wearable electronics, as their multiple functionalities of electric power generation, photopermeability, and color tunability. Design and exploration of semitransparent organic solar cells with optimal and balanced efficiency and average visible light transmittance and simultaneously high stability are in great demand. In this work, based on a layer-by-layer-processed active layer and an ultrathin metal electrode, inverted semitransparent organic solar cells (ITO/AZO/PM6/BTP-eC9/MoO₃/Au/Ag) were fabricated. Optimal and balanced efficiency and average visible light transmittance were demonstrated, and simultaneously promising thermal and light stability were achieved for the obtained devices. The power conversion efficiency of 13.78–12.29% and corresponding average visible light transmittance of 14.58–25.80% were recorded for the ST-OSC devices with 25–15 nm thick Ag electrodes, respectively. Superior thermal and light stability with ~90% and ~85% of initial efficiency retained in 400 h under 85 ℃ thermal stress and AM1.5 solar illumination were demonstrated, respectively.

The prediction of two-dimensional molecular self-assembly structures has always been a problem to be solved. The molecules with meta-dicarboxyl groups can self-assemble into a specific hexagonal cavity, which has an important influence on the prediction of molecular self-assembly structures and the application of functional molecules with meta-dicarboxyl groups. Two kinds of molecules with four pairs of meta-dicarboxyl groups, 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene (H₈TIAPy) and 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1’-biphenyl]-3,5-dicarboxylic acid)) (H₈ETTB) molecules were chosen to observe the self-assembly behavior at the heptanoic acid/highly oriented pyrolytic graphite (HA/HOPG) interface. H₈TIAPy molecules self-assembled into well-ordered quadrilateral structures and could be regulated into kagomé networks with hexagonal pores by coronene (COR) molecules. H₈ETTB molecules self-assembled into lamellar structures and transformed into acid-COR-acid-COR co-assembled structures at low concentration of COR solution and acid-COR dimer-acid-COR dimer co-assembled structures at high concentration of COR solution. The reason that H₈ETTB molecules could not be regulated into hexagonal porous architecture was attributed to the steric hindrance by the similar length and width of H₈ETTB molecules. The H₈ETTB templates had stronger adsorption for COR than that of hexaphenylbenzene (HPB), regardless of the order of molecular introduction.