According to Kasha's rule, high-lying excited states usually have little effect on fluorescence. However, in some molecular systems, the high-lying excited states partly or even mainly contribute to the photophysical properties, especially in the process of harvesting triplet excitons in organic electroluminescent devices. In the current review, we focus on a type of organic light-emitting diode (OLED) materials called “hot exciton” materials, which can effectively harness the non-radiative triplet excitons via reverse intersystem crossing (RISC) from high-lying triplet states to singlet states (Tn → Sm; n ≥ 2, m ≥ 1). Since Ma and Yang proposed the hot exciton mechanism for OLED material design in 2012, there have been many reports aiming at the design and synthesis of novel hot exciton luminogens. Herein, we present a comprehensive review of the recent progress in hot exciton materials. The developments of the hot exciton mechanism are reviewed, the fundamental principles regarding molecular design are discussed, and representative reported hot exciton luminogens are summarized and analyzed, along with their structure–property relationships and OLED applications.

Recent progress in hot exciton materials for organic light-emitting diodes

Recent challenges in biomedical diagnostics show that the development of rapid affinity sensors is very important issue. Therefore, in this review we are aiming to outline the most important directions of affinity sensors where polymer-based semiconducting materials are applied. Progress in formation and development of such materials is overviewed and discussed. Some applicability aspects of conducting polymers in the design of affinity sensors are presented. The main attention is focused on bioanalytical application of conducting polymers such as polypyrrole, polyaniline, polythiophene and poly(3,4-ethylenedioxythiophene) ortho-phenylenediamine. In addition, some other polymers and inorganic materials that are suitable for molecular imprinting technology are also overviewed. Polymerization techniques, which are the most suitable for the development of composite structures suitable for affinity sensors are presented. Analytical signal transduction methods applied in affinity sensors based on polymer-based semiconducting materials are discussed. In this review the most attention is focused on the development and application of molecularly imprinted polymer-based structures, which can replace antibodies, receptors, and many others expensive affinity reagents. The applicability of electrochromic polymers in affinity sensor design is envisaged. Sufficient biocompatibility of some conducting polymers enables to apply them as “stealth coatings” in the future implantable affinity-sensors. Some new perspectives and trends in analytical application of polymer-based semiconducting materials are highlighted.

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Advances in molecularly imprinted polymers based affinity sensors (review)

Organophosphorus compounds are toxic organic phosphorus molecules including nerve agents and pesticides. Organophosphorus pesticides play a significant role in improving large-scale modern agriculture. Nerve agents are neurotoxic chemicals. Therefore, there is a demand for assays to measure organophosphorus analogs in a rapid, sensitive, and convenient way. Here, colorimetric and fluorescence sensors can be an effective approach for sensing these substances. They have been extensively explored due to their portability and high sensitivity. This review summarizes recent development in colorimetric and fluorescent materials including small organic fluorophores, nanomaterials, complexes, and polymers since 2015. We describe advances in sensing a variety of organophosphorus analogs. We also discuss recent challenges and design strategies in developing colorimetric and fluorescent assays with high performance and specific sensing.

Colorimetric and fluorescent sensors for detection of nerve agents and organophosphorus pesticides

Facile Fabrication of Luminescent Eu(III) Functionalized HOF Hydrogel Film with Multifunctionailities: Quinolones Fluorescent Sensor and Anticounterfeiting Platform

Further development of high-efficiency and low-cost organic fluorescent materials is intrinsically hampered by the energy gap law and spin statistics, especially in the near-infrared (NIR) region. Here we design a novel building block with aggregation-induced emission (AIE) activity for realizing highly efficient luminophores covering the deep-red and NIR region, which originates from an increase in the orbital overlap and electron-withdrawing ability. An organic donor–acceptor molecule (BPMT) with the building block is prepared and can readily form J-type molecular columns with multiple C–H⋯N/O interactions. Notably, such synthesized materials can emit fluorescence centered at 701 nm with extremely high photoluminescence quantum yields (PLQYs) of 48.7%. Experimental and theoretical investigations reveal that the formation of the hybridized local and charge-transfer (HLCT) state and substantial C–H⋯N/O interactions contribute to a fast radiative decay rate and a slow nonradiative decay rate, respectively, resulting in high PLQYs in the solid state covering the NIR range. Remarkably, such BPMT crystals, as a first example, reveal strong-penetrability piezochromism along with a distinct PL change from the deep-red (λmax = 704 nm) to NIR (λmax = 821 nm) region. Moreover, such typical AIE-active luminophores are demonstrated to be a good candidate as a lasing medium. Together with epoxy resin by a self-assembly method, a microlaser is successfully illustrated with a lasing wavelength of 735.2 nm at a threshold of 22.3 kW cm−2. These results provide a promising approach to extend the contents of deep-red/NIR luminophores and open a new avenue to enable applications ranging from chemical sensing to lasing.

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A highly emissive AIE-active luminophore exhibiting deep-red to near-infrared piezochromism and high-quality lasing.

Dendrimer‐Based, High‐Luminescence Conjugated Microporous Polymer Films for Highly Sensitive and Selective Volatile Organic Compound Sensor Arrays

Simple and fast detection of chemical warfare agents vapor is necessary and urgent to fight against uncertain terrorist attacks and wars. In this contribution, inspired by the design of the hybrid ...

Visualization of Ultrasensitive and Recyclable Dual-Channel Fluorescence Sensors for Chemical Warfare Agents Based on the State Dehybridization of Hybrid Locally Excited and Charge Transfer Materials

A new strategy for selective fluorescence detection of benzaldehyde and nitrobenzene

An “on-off-on” fluorescent system based on the microwave-assisted preparation of copper-functionalized carbon quantum dots for sensitive detection of ascorbic acid

Wanqi Mo

Papers

Dendrimer‐Based, High‐Luminescence Conjugated Microporous Polymer Films for Highly Sensitive and Selective Volatile Organic Compound Sensor Arrays

Visualization of Ultrasensitive and Recyclable Dual-Channel Fluorescence Sensors for Chemical Warfare Agents Based on the State Dehybridization of Hybrid Locally Excited and Charge Transfer Materials

A new strategy for selective fluorescence detection of benzaldehyde and nitrobenzene

An “on-off-on” fluorescent system based on the microwave-assisted preparation of copper-functionalized carbon quantum dots for sensitive detection of ascorbic acid