Chaoyuan Zeng

To enhance both the efficiency and stability of perovskite solar cells (PSCs), an ideal interface needs to be formed; that is, defect passivation, efficient charge transport and suppression of ion migration must be achieved simultaneously. We rationally designed a series of multifunctional pseudohalide (PH) anions in this study, including APCA, APCA2OH, and APCA3OH, and systematically and synergistically regulated the interfacial properties by introducing functional groups such as -COO-, -OH, -NH2, -CN, and aromatic rings. First-principles calculations and ab initio molecular dynamics (AIMD) simulations indicate that the optimal APCA3OH molecule anchors to the perovskite surface via strong multidentate chelation. Cooperative coordination can reduce both deep and shallow trap states effectively by breaking up the harmful Pb3 trimers and Pb2 dimers associated with Pb-I antisite (PbI) and iodine vacancy (VI) defects. From an electronic standpoint, the intrinsic dipole moments of the designed PH anions can adjust the surface work function to reduce the energy-level mismatch at the electron-selective contact and promote non-radiative carrier extraction. In addition, the synergistic chemical bonding and prominent steric hindrance caused by the ortho-hydroxyl group in APCA3OH increase the activation energy for iodide migration to 10.72 eV and thus inhibit halide diffusion. The functionalized structure also forms a dense hydrogen-bonding network that restricts water infiltration and enhances dynamic stability. By elucidating the structure-activity relationships of these complex molecular architectures, this work provides fundamental molecular insights for the design of comprehensive interfacial passivants for future perovskite photovoltaics.

Design and application of the probe DEA-PT-Py.

The SSF probe enables the detection of environmental microplastics and cell polarity.

Cysteine (Cys) is an essential sulfur-containing amino acid in the human body and is involved in many important physiological processes. The reliable detection of Cys is of great significance for the precise diagnosis of diseases. Fluorescent probes are powerful tools for the detection of Cys. In the study, we designed and synthesized a series of Cys-recognizable fluorescent probes by employing different recognition groups and conjugated units. Our results demonstrated that the probe based on acrylate and acrolein emits almost no fluorescence in organic solvents, whereas it achieved a near-infrared fluorescence emission (652 nm) due to the excited-state intramolecular proton transfer (ESIPT) effect in the presence of Cys. Importantly, the probe exhibited high selectivity and fast response time (in 10 min). In particular, the limit of detection (LOD) is as low as 3.42 × 10⁻⁴ µM. This probe has been successfully applied for the detection and imaging of Cys in biological cells.

Methylation steric hindrance lowers HR factors and reorganization energy, boosting fluorescence and enabling selective in vivo HClO imaging.