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The investigation on the catalytic properties of porous organic cages is still in an initial stage. Herein, the reaction of cyclohexanediamine with 5,15-di[3',5'-diformyl(1,1'-biphenyl)]porphyrin affords a porphyrin tubular organic cage, PTC-1(2H). Transient absorption spectroscopy in solution reveals much prolonged triplet lifetime of PTC-1(2H) relative to monomer reference, illustrating the unique photophysical behavior of cagelike photosensitizer. The long triplet lifetime ensures high-efficiency singlet oxygen evolution according to homogeneous photo-bleach experiment, electron spin-resonance spectroscopy, and aerobic photooxidation of benzylamine. Furthermore, microporous supramolecular framework of PTC-1 (2H) is able to promote the heterogeneous photo-oxidation of various primary amines with conversion efficiency above 99% under visible light irradiation. These results indicate the great application potentials of porous organic cages in heterogeneous phase.

A linear tetracene trimer linked by phenyl groups has been prepared for the first time. The triplet quantum yield formed via intramolecular singlet fission can reach up to 96% in this trimer, which is enhanced significantly compared with that in the dimer. This can be attributed to the stronger electronic coupling between tetracene subunits and more delocalized excitons in the trimer.

Ar obust 2,2'-bipyridine (bpy)-derived biological hydrogen-bonded framework (HOF-25) has been realized depending on guanine-quadruplex with the assistance of p-p interaction, which reacts with Re(CO) 5 Cl to give ap ost-functionalizedH OF-25-Re.X-raya bsorption fine structure spectroscopic study on HOF-25-Re confirms the covalent attachment of Re(bpy)(CO) 3 Cl segments to this HOF.R obust and recycled HOF-25-Re bearing photocatalytic Re(bpy)-(CO) 3 Cl centers displays good heterogeneous catalytic activity towards carbon dioxide photoreduction in the presence of [Ru(bpy) 3 ]Cl 2 and triisopropanolamine in CH 3 CN under visible-light irradiation, with both high CO production rate of 1448 mmol g À1 h À1 and high selectivity of 93 %. Under the same conditions,t he experimental turnover number of HOF-25-Re (50) is about 8times as that of the homogeneous control Re(bpy)(CO) 3 Cl. The sustainably regenerated HOF-25-Re via crystallization and post-modification processes shows recovered photocatalytic performance.

A covalently linked tetracene dimer has been prepared and its molecular structure is characterized by (1)H NMR and MALDI-TOF mass spectroscopy, and elemental analysis. The minimized molecular structure reveals that the tetracene subunits in a dimer adopt a "face-to-face" stacked configuration. Its absorption spectrum differs significantly from that of the monomeric counterpart in solution, suggesting the presence of strong interactions between the two tetracene subunits. In solution, the fluorescence spectrum is dominated by a band at around 535 nm, due to an oxidative impurity. In the longer wavelength range, a short-lived lower energy emission can be identified as the intrinsic emission of the dimer. In a polystyrene matrix or at low temperatures, the lifetime of the lower energy emission lengthens and it becomes more prominent. We suggest that the interactions between the two tetracene subunits produce a short-lived, lower energy "excimer-like" state. The fluorescence decays show no observable dependence on an applied magnetic field, and no obvious evidence of significant singlet fission is found in this dimer. This research suggests that even though there are strong electronic interactions between the tetracene subunits in the dimer, singlet fission cannot be achieved efficiently, probably because the formation of "excimer-like" states competes effectively with singlet fission.

Covalently linked perylenetetracarboxylic diimide (PDI) dimers (D1 and D2) and trimers (T1 and T2) with slipped “face-to-face” stacked structure are prepared and their molecular structures are characterized by 1H NMR, MALDI-TOF mass spectroscopy and elemental analysis. The rigid molecular structures of these compounds make it easier to establish a direct correlation between the aggregate structure and the photophysical properties. The minimized molecular structures of these compounds reveal that they are all “face-to-face” stacked aggregates with large longitudinal displacement. Their absorption spectra show red-shifted bands, suggesting the presence of “J” type excitonic coupling between the PDI subunits in these compounds. However, their steady state and time resolved fluorescence spectra revealed that the emission from the “excimer-like” states dominates the fluorescence of these compounds, this is similar to that of “H-type” aggregates and may be ascribed to the “face-to-face” stacked structure. In the fluorescence spectra of these compounds, a minor “J-type” emission can be identified for the compounds with a relatively large longitudinal displacement. An increase in the number of subunits in one aggregate from 2 to 3 also brings about distinctive changes in their photophysical properties, which can be ascribed to the changes in the stacking structure caused by the steric hindrance.

Surface passivation is a widely used approach to promote the efficiency and stability of perovskite solar cells (PSCs). In the present project, a series of new organic surface passivation molecules, which contain the same triphenylamino group with the hole transfer material of PSCs, have been synthesized. These new passivation molecules are supposed to have both "carrier transfer" capability and "defect passivation" potential. We find that, by using N-((4-(N,N,N-triphenyl)phenyl)ethyl)ammonium bromide (TPA-PEABr) as a surface passivation molecule, the efficiency of the PSCs can be improved from 16.69 to 18.15%, mainly due to an increased Voc (1.09 V compared with 1.02 V in control devices). The increased Voc is due to the reduced surface defect density and a better alignment for the related energy levels after introducing the TPA-PEABr molecules. Moreover, the stability of the PSCs can be significantly improved in TPA-PEABr passivated devices due to the hydrophobic nature of TPA-PEABr. Our results successfully demonstrate that passivation of the perovskite surface with a carefully designed multifunctional small organic molecule should be a useful approach for more stable PSCs with high efficiency.

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