Running rings around mercuric ions: A [26]hexaphyrin(1.1.1.1.1.0), comprising an α,α′‐bipyrrole unit and four pyrrolic and five pentafluorophenyl rings, was prepared and characterized by X‐ray crystallography (see picture; N blue, F green, C black). The expanded porphyrin displays near‐infrared luminescence above 900 nm and may serve as a highly sensitive and selective chemodosimeter for Hg2+ ions.

To develop new hole-transporting materials (HTMs) for efficient and stable perovskite solar cells (PSCs), 5,10,15,20-tetrakis{4-[N,N-di(4-methoxylphenyl)amino-phenyl]}-porphyrin was prepared in gram scale through the direct condensation of pyrrole and 4-[bis(4-methoxyphenyl)amino]benzaldehyde. Its Zn(II) and Cu(II) complexes exhibit excellent thermal and electrochemical stability, specifically a high hole mobility and very favorable energetics for hole extraction that render them a new class of HTMs in organometallic halide PSCs. As expected, ZnP as HTM in PSCs affords a competitive power conversion efficiency (PCE) of 17.78%, which is comparable to that of the most powerful HTM of Spiro-MeOTAD (18.59%) under the same working conditions. Meanwhile, the metal centers affect somewhat the photovoltaic performances that CuP as HTM produces a lower PCE of 15.36%. Notably, the PSCs employing ZnP show a much better stability than Spiro-OMeTAD. Moreover, the two porphyrin-based HTMs can be prepared from relatively cheap raw materials with a facile synthetic route. The results demonstrate that ZnP and CuP can be a new class of HTMs for efficient and stable PSCs. To the best of our knowledge, this is the best performance that porphyrin-based solar cells could show with PCE > 17%.

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N-rich metal-free and metal-doped carbon quantum dots (CQDs) have been prepared through one-step hydrothermal method using tetraphenylporphyrin or its transition metal (Pd or Pt) complex as precursor. The structures and morphology of the as-prepared nanoparticles were analyzed by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectra. Three kinds of nanocomposites show similar structures except for the presence of metal ions in Pd-CQDs and Pt-CQDs indicated by X-ray photoelectron spectroscopy. All of them display bright blue emission upon exposure to ultraviolet irradiation. The CQDs exhibit typical excitation-dependent emission behavior, with the emission quantum yield of 10.1%, 17.8%, and 15.2% for CQDs, Pd-CQDs, and Pt-CQDs, respectively. Moreover, the CQDs, Pd-CQDs, and Pt-CQDs could serve as fluorescent probes for the specific and sensitive detection of Fe 3+ ions in aqueous solution. The low cytotoxicity of CQDs is demonstrated by MTT assay against HeLa cells. Therefore, the CQDs can be used as efficient probes for cellular multicolor imaging and fluorescence sensors for the detection of Fe 3+ ions due to their low toxicity, excellent biocompatibility, and low detection limits. This work provides a new route to synthesize highly luminescent N-rich metal-free or metal-doped CQDs for multifunctional applications.