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Phototheranostic agents have thrived as promising tools for cancer theranostics because of the integration of sensitive in situ fluorescence imaging and effective multi-model synergistic therapy. However, how to manipulate the intangible photon energy transfer to balance the competitive radiative and nonradiative processes is still challenging. Although numerous phototheranostic molecules are reported, their complicated molecular design and tedious synthesis often stumble further their development. Herein, three simple molecules with electron donating−accepting structures are developed. The electron acceptor engineering on molecules by introducing acridinium unit gives rise to TPEDCAc with aggregation-induced second near-infrared emission (AIE NIR-II), high reactive oxygen species generation capability, and excellent photothermal conversion efficiency (44.8%) due to the drastic intramolecular motion of large acridinium rotor and balanced AIE effect. Experimental analysis and calculation on the controlled molecules suggested that large torsional angle and the strong electron-withdrawing ability of the acridinium unit are keys for NIR-II emission and balanced photodynamic/photothermal conversion. Impressively, the positively charged TPEDCAc shows mitochondria-targeting capability and high performance in in vivo multi-modal cancer theranostics under NIR laser irradiation. Hence, this work not only provides a single NIR-II AIE-based multi-modal cancer theranostic system but inspires new insights into future development of new theranostic platforms. © 2022 Wiley-VCH GmbH

Stable organic radicals are promising materials for information storage, molecular magnetism, electronic devices, and biological probes. Many organic radicals have been prepared, but most are non- or weakly emissive and degrade easily upon photoexcitation. It remains challenging to produce stable and efficient luminescent radicals because of the absence of general guidelines for their synthesis. Herein, we present a photoactivation approach to generate a stable luminescent radical from tris(4-chlorophenyl)phosphine (TCPP) with red emission in the crystal state. The mechanistic study suggests that the molecular symmetry breaking in the crystal causes changes of molecular conformation, redox properties, and molecular packing that facilitates radical generation and stabilization. This design strategy demonstrates a straightforward approach to develop stable organic luminescent radicals that will open new doors to photoinduced luminescent radical materials.

The development of solid-state intelligent materials, in particular those showing photoresponsive luminescence (PRL), is highly desirable for their cutting-edge applications in sensors, displays, data-storage, and anti-counterfeiting, but is challenging. Few PRL materials are constructed by tethering the classic photochromic systems with newly-emerged solid-state emitters. Selective solid-state photoreactions are demanded to precisely manipulate the luminescent behavior of these emitters, which require dramatic structural change and enough free space, thus limiting the scope of the PRL family. Here, a new PRL material, TPE-4N, that features sensitive and reversible fluorescence switching is reported. The interesting on–off luminescent property of TPE-4N can be facilely tuned through fast phototriggering and thermal annealing. Experimental and theoretical investigations reveal that subtle molecular conformation variation induces the corresponding PRL behavior. The crystalline and amorphous state endows an efficient and weak ISC process, respectively, to turn on and off the emission. The readily fabricated thin-film of TPE-4N exhibits non-destructive PRL behavior with high contrast (>102), good light transmittance (>72.3%), and great durability and reversibility under room light for months. Remarkably, a uniform thin-film with such fascinating PRL properties allows high-tech applications in invisible anti-counterfeiting and dynamic optical data storage with micro-resolution. © 2020 Wiley-VCH GmbH

Stable organic radicals are promising materials for information storage, molecular magnetism, electronic devices, and biological probes. Many organic radicals have been prepared, but most are non- or weakly emissive and degrade easily upon photoexcitation. It remains challenging to produce stable and efficient luminescent radicals because of the absence of general guidelines for their synthesis. Herein, we present a photoactivation approach to generate a stable luminescent radical from tris(4-chlorophenyl)phosphine (TCPP) with red emission in the crystal state. The mechanistic study suggests that the molecular symmetry breaking in the crystal causes changes of molecular conformation, redox properties, and molecular packing that facilitates radical generation and stabilization. This design strategy demonstrates a straightforward approach to develop stable organic luminescent radicals that will open new doors to photoinduced luminescent radical materials.

Because of their innate ability to store and then release energy, long-persistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic systems have had difficulties reaching similar timescales. In this work, a design principle based on the successes of inorganic systems to produce an organic LPL (OLPL) system through the use of a strong organic electron trap is proposed. The resulting system generates detectable afterglow for up to 7 h, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long-persistent phosphors, opening the door to new OLPL materials. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A pentagonal macrocycle (MC5-PER) with radialene topology was facilely synthesized through a selective one-pot Suzuki-Miyaura cross-coupling reaction. The resulting product is endowed with a pentagonal architecture as revealed by its single crystal structure, which affords the smallest ring strain and the best conjugation. As tetraphenylethene subunits are embedded, MC5-PER is highly emissive in the solid state due to the aggregation-induced emission effect. Because of the flexible structure and preferable fibre-like self-assembly, the aggregate of MC5-PER displays interesting polymorphism-dependent emission and acts as a sensitive fluorescence sensor for explosives detection.