Science China Chemistry最新文献

Nonionic poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA)-based inverted wide-bandgap perovskite solar cells (PSCs) are pivotal for advancing all-perovskite tandem architectures and indoor photovoltaics, yet their performance is fundamentally constrained by the hydrophobic nature of PTAA. Herein, we demonstrate a dual-interface molecular engineering strategy to synchronously modulate the perovskite-facing upper interface and substrate-contacting buried interface of PTAA using hydrophilic poly(methyl methacrylate) (PMMA) and poly(3-carboxypentyl thiophene) (P3CT-N). The carbonyl (C=O) groups in PMMA and P3CT-N synergistically enhance interfacial wettability, promoting the controlled crystallization of 1.78 eV wide-bandgap perovskites. Additionally, the carbonyl coordination effectively passivates undercoordinated Pb²⁺ defects, improving charge transport dynamics. Meanwhile, vacuum-level shifting induced by the interface dipole of PMMA and P3CT-N optimizes valence-band alignment, facilitating efficient hole extraction. As a result, the modified PTAA-based single-junction PSCs achieve a remarkable power conversion efficiency (PCE) of 19.38% under AM 1.5G illumination, significantly surpassing the 17.06% of pristine PTAA devices. The sandwich polymer structure-based PTAA design further enhances indoor photovoltaic performance, yielding PCEs of 37.43% and 30.09% under 1000 lux and 200 lux LED illumination, respectively. Moreover, in all-perovskite tandem configurations, the modified hole transport layer (HTL) enables a remarkable PCE of 26.87% under AM 1.5G illumination, outperforming control devices (25.38%). This strategy provides a robust pathway toward highly efficient and stable indoor and all-perovskite tandem photovoltaics based on wide-bandgap perovskite.

Hydrogen species participate in the whole process of electrochemical CO₂ reduction, which is traditionally treated as a negative factor from the competitive hydrogen evolution reaction. Here, we illustrate for the first time that the rapid transfer of hydrogen species can significantly promote the deep reduction of CO₂ to ethylene products on copper-based catalysts. We construct a hydrogen transfer channel on Cu₂O nanowires by introducing a conductive copper meso-tetra(4-carboxyphenyl)porphine (Cu-TCPP) layer, where the Cu nodes can adsorb H₂O and the coordinated carboxyl group can adsorb H_ad simultaneously. The hydrogen species from the bulk solution are transferred to the CO₂ reduction step by forming H₃O⁺ with target H₂O and exchanging with the adsorbed H_ad. Density functional theory (DFT) calculations reveal that the channel eventually facilitates the continuous exothermic hydrogenation reaction of the C₂ intermediate towards ethylene production, which accelerates the ethylene generation with the highest faradic efficiency of 78.6% in neutral conditions in H-cells.

Chiral supramolecular polyelectrolyte nanoporous membranes (CSPPMs) are increasingly important owing to their potential applications in sensing, separation technology, and bioengineering. However, developing such membranes remains challenging due to the lack of suitable synthetic approaches. Herein, we introduce a facile and conceptual approach that uses water molecules as dynamic crosslinkers and pore-forming agents to create CSPPMs from single-component chiral poly(ionic liquid)s. The experimental and theoretical calculation results demonstrated that the supramolecular network of CSPPMs was crosslinked by hydrogen (H)-bonding, C–H⋯π, electrostatic, and π-π interactions. During pore architecture formation in the membranes, an intriguing chiral amplification phenomenon was observed. This phenomenon, combined with the unique fluorescence properties and high enantioselectivity of CSPPMs toward chiral guest molecules, enables easy discrimination of enantiomers under UV lamps or even with the naked eye. The knowledge gained from this fundamental study could serve as a springboard for developing multifunctional chiral polyelectrolyte membranes for diverse applications.

With this research, we introduce and validate the cyclization-regulated fluorescence emission (CRFE) as a photophysical mechanism that activates fluorescence through chemically triggered cyclization. This mechanism, developed from traditional fluorescence principles, generates fluorescence emission only when the rigidity of the lower part of the molecule increases through cyclization, while still satisfying the conditions of other fluorescence mechanisms. The universality of this mechanism was verified in multiple conjugate acceptors derived by integrating different fluorophores into a single conjugated acceptor via Suzuki coupling. The photophysical properties of these molecules were characterized, with density functional theory (DFT) calculations providing insight into the conformational and electronic changes occurring during excitation. It is concluded that cyclization stabilizes the conjugated double bond during excitation, facilitating fluorescence emission. Guided by the mechanism and chemical reactivity, a typical fluorescent probe was exploited for the selective labeling of vicinal thiol groups on target proteins, both in vitro and in living cells. This work presents a new pathway for the design of fluorescent probes with activable photoluminescence, highlighting the potential applications in bioimaging, protein dynamics tracking, and biosensing.

Photodynamic therapy (PDT) and photothermal therapy (PTT) synergistic treatment for hypoxic tumors, always requires high-intensity light irradiation. This study introduces an intramolecular modulation approach for achieving PDT and PTT synergy under gentle light irradiation via the formation of tightly packed J-aggregated nanorings. Specifically, cyanine dyes, designated as TYA and TYB, were synthesized and compared to investigate the influence of intramolecular and intermolecular forces on the formation of compact J-aggregates. Compared to TYA (14.22°, 8.58 Å), the planar quinoline moieties in TYB exhibit a more pronounced rotation around the methylene linker (50.21°), which facilitates intermolecular slippage and reduces the stacking distance to 4.91 Å in J-aggregated nanorings (TYB J-NPs). The smaller monomer separations facilitate the generation of photothermal effects under mild light irradiation. These TYB J-NPs generate reactive oxygen species (ROS) levels comparable to those produced by TYA J-aggregates, while simultaneously producing a thermal effect under near-infrared (NIR) light irradiation (35 mW/cm², 10 min, ΔT > 20 °C). This dual functionality synergistically enables in vivo fluorescence and photothermal imaging, and effectively inhibits the growth and invasion of 4T1 tumors in mice. Moreover, TYB J-NPs demonstrate substantial antibacterial efficacy against both Gram-positive and Gram-negative bacteria, thereby offering effective antibacterial protection during tumor phototherapy. In summary, the intramolecular twisting of TYB effectively resolves the bottleneck associated with intermolecular repulsions at large molecular separations, thereby facilitating the formation of densely packed J-aggregates. This represents the first instance where J-aggregated nanorings enable concurrent PDT and PTT with antibacterial effectiveness under low-density NIR light irradiation. This work may significantly enhance the therapeutic potential of cyanine dyes in cancer treatment, pathogenic bacterial infections, and other diseases.