Dinuclear metal complexes have enabled breakthroughs in OLEDs, photocatalytic water splitting and CO2 reduction, DSPEC, chemosensors, biosensors, PDT and smart materials.

The singlet oxygen (1O2) generation ability of a photosensitizer (PS) is pivotal for photodynamic therapy (PDT). Transition metal complexes are effective PSs, owing to their high 1O2 generation ability. However, non‐negligible cellular toxicity, poor biocompatibility, and easy aggregation in water limit their biomedical applications. In this work, a series of red‐emitting aggregation‐induced emission (AIE) Ir(III) complexes containing different numbers of Ir centers (mono‐, di‐, and trinuclear) and the corresponding nanoparticles (NPs) AIE‐NPs, are designed and synthesized. The increase of 1O2 generation ability is in line with the increasing number of Ir centers. Compared with the pure Ir(III) complexes, the corresponding NPs offer multiple advantages: (i) brighter emission; (ii) higher phosphorescence quantum yields; (iii) longer excited lifetime; (iv) higher 1O2 generation ability; (v) better biocompatibility; and (vi) superior cellular uptake. Both in vitro and in vivo experiments corroborate that AIE‐NPs with three iridium centers possess potent cytotoxicity toward cancer cells and effective inhibition of tumor growth. To the best of knowledge, this work is the first example of NPs of multinuclear AIE Ir(III) complexes as PSs for enhanced PDT. This study offers a new method to improve the efficiency of PSs for clinical cancer treatments.

Eight new iridium(III) complexes 1‐8, with 1,3,4‐oxadiazole (OXD) derivatives as the cyclometalated C^N ligand and/or the ancillary N^N ligands are synthesized and their electrochemical, photophysical, and solid‐state light‐emitting electrochemical cell (LEC) properties are investigated. Complexes 1, 2, 7 and 8 are additionally characterized by single crystal X‐ray diffraction. LECs based on complexes 1‐8 are fabricated with a structure indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/cationic iridium complex:ionic liquid/Al. LECs of complexes 1–6 with OXD derivatives as the cyclometalated ligands and as the ancillary ligand show yellow luminescence (λmax = 552–564 nm). LECs of complexes 7 and 8 with cyclometalated C^N phenylpyridine ligands and an ancillary N^N OXD ligand show red emission (λmax 616–624 nm). Using complex 7 external quantum efficiency (EQE) values of >10% are obtained for devices (210 nm emission layer) at 3.5 V. For thinner devices (70 nm) high brightness is achieved: red emission for 7 (8528 cd m−2 at 10 V) and yellow emission for 1 (3125 cd m−2 at 14 V).

The past few years have witnessed the rapid development of carbon dots (CDs) due to their outstanding optical properties and a wide range of applications. However, the design and control of CDs with long-wavelength multicolor emission are still huge challenges to be addressed for their practical use in different fields. Here, novel nitrogen-doped multiple-core@shell-structured AC-CDs with tricolor emissions of red, green, and blue were constructed via one-pot hydrothermal method from 5-amino-1,10-phenanthroline and citric acid as reactants and the growth process of AC-CDs was monitored with the reaction time in the synthetic system. The origin of different fluorescence emissions was explored using the unique coordination ability of the surface groups of AC-CDs. An obvious concentration dependence of fluorescent properties was observed for the as-prepared AC-CDs, and a highly fluorescent quantum yield (QY) of 67% for red emission at 630 nm can be obtained by adjusting concentration of AC-CDs. The pure white-light emission (0.33, 0.33; Commission Internationale de l'Elcairage coordinate) was carried out from single carbon dot with QY of 29% through regulation of the excitation and concentration of multiple-core@shell-structured AC-CDs. In addition, because of their excellent photoluminescent properties, the white-emitting AC-CDs as emitting phosphor can be easily used in the fabrication of white-light-emitting diode with good anti-photobleaching and temperature stability.