Stimuli-Responsive Purely Organic Room-Temperature Phosphorescence Materials

This Minireview summarizes the recent progress of stimuli-responsive purely organic phosphorescence materials. Organic phosphorescence is closely related to the intermolecular interactions, because such interactions are beneficial to promote spin orbital coupling (SOC) and boost intersystem cross (ISC) efficiency and finally are conducive to satisfactory phosphorescence. It is found that the intermolecular interactions, which are essential for organic phosphorescence, are easily disturbed by external stimuli such as mechanical force, photon, acid, chemical vapor, leading to the luminescence change. According to this principle, various purely organic phosphorescence materials sensitive to external stimuli have been developed. This Minireview categorizes reported stimuli-responsive purely organic phosphorescence materials on the basis of different stimuli, including mechanochromism, mechanoluminescence, photoactivity, acid-responsiveness and other stimuli. Some prospective strategies for constructing stimuli-responsive purely organic phosphorescence molecules are provided.     

固体基质室温磷光发光机理进展

本文从磷光体在基质中的分布、磷光体与基质中重原子的作用和磷光体基质中的刚性化三个方面对固体基质室温磷光发光机理进行了详细评述,着重介绍了磷光体与基质之间的作用 ,并对研究前景进行了讨论。     

Molecular Engineering for Metal-Free Amorphous Materials with Room-Temperature Phosphorescence

Materials displaying room-temperature phosphorescence (RTP) have been attracting wide attention in recent years due to their distinctive characteristics including long emissive lifetime and large Stokes shift, and their various applications. Most synthesized RTP materials are metal complexes that display enhanced intersystem crossing and crystallization is a common way to restrict nonradiative transition. Amorphous metal-free RTP materials, which do not rely on expensive and toxic metals and can be prepared in a straightforward fashion, have become an important branch of the field. This Minireview summarizes recent progress in amorphous RTP materials according to the approaches used to immobilize phosphors: host–guest interactions, molecule doping, copolymers, and small-molecule self-assembly. Some existing challenges and insightful perspectives are given at the end of the Minireview, which should benefit the future design and development of amorphous metal-free RTP materials.     

Stimuli‐Responsive Circularly Polarized Organic Ultralong Room Temperature Phosphorescence

Purely organic materials showing room temperature phosphorescence (RTP) and ultralong RTP (OURTP) have recently attracted much attention. However, it is challenging to integrate circularly polarized luminescence (CPL) into RTP/OURTP. Here, we show a strategy to realize CPL‐active OURTP (CP‐OURTP) by binding an achiral phosphor group directly to the chiral center of an ester chain. Engineering of this flexible chiral chain enables efficient chirality transfer to carbazole aggregates, resulting in strong CP‐OURTP with a lifetime of over 0.6 s and dissymmetry factor of 2.3×10^?3 after the conformation regulation upon photo‐activation. The realized CP‐OURTP is thus stable at room temperature but can be deactivated quickly at 50 °C to CP‐RTP with high CPL stability during the photo‐activation/thermal‐deactivation cycles. Based on this extraordinary photo/thermal‐responsive and highly reversible CP‐OURTP/RTP, a CPL‐featured lifetime‐encrypted combinational logic device has been successfully established.     

环糊精诱导室温磷光发光机理研究进展

本文综述了环糊精诱导室温磷光发光机理，并对得原子作用及除氧技术作了介绍。     

H-Bonding Room Temperature Phosphorescence Materials via Facile Preparation for Water-Stimulated Photoluminescent Ink

Pure organic room-temperature phosphorescence (RTP) materials built upon noncovalent interactions have attracted much attention because of their high efficiency, long lifetime, and stimulus-responsive behavior. However, there are limited reports of noncovalent RTP materials because of the lack of specific design principles and clear mechanisms. Here, we report on a noncovalent material prepared via facile grinding that can emit fluorescence and RTP emission differing from their components’ photoluminescent behavior. Exciplex can be formed during the preparation process to act as the minimum emission unit. We found that H-bonds in the RTP system provide restriction to nonradiative transition but also enhance energy transformation and energy level degeneracy in the system. Moreover, water-stimulated photoluminescent ink is produced from the materials to achieve double-encryption application with good resolution.     

色氨酸无保护流体室温燐光和胶束增稳室温燐光性质的比较

研究了色氨酸的无保护流体室温燐光和以非离子表面活性剂Tween 20、Tween 40、Tween 80、Tween 85、Brij35、TritonX 100、乳化剂OP及高分子分散剂聚乙二醇 200(PEG 200)、PEG 400为介质的流体室温燐光 性质。直接用于大米、花生、大豆及竹笋中色氨酸的测定,相对标准偏差2.26%～3.28%,与荧光法比较,相 对误差-3.9%～4.2%。     

钯卟啉室温燐光氧传感器的研究

以Dowex 5 0× 2 1 0 0树脂为载体固定四 (三甲氨基苯基 )钯卟啉 (Pd TAPP) ,利用其光被氧猝灭的特性 ,采用流动注射分析 (FIA)技术 ,制成氧传感器。该方法响应快 (响应时间从氮气到氧气为 1 8s,反之为86s) ,灵敏度高 (I0 I1 0 0 值为 5 .6) ,检测限可达 0 .0 9% (V V)。     

Clustering-Triggered Efficient Room-Temperature Phosphorescence from Nonconventional Luminophores

Pure organic room-temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Herein, we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boosts the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5 % is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results will spur the future fabrication of nonconventional phosphors and advance the understanding of the underlying emission mechanism.     

无保护流体室温磷光法测定1-萘胺的研究

研究了 1 -萘胺 ( NNA)的无保护流体室温磷光 ( NP- RTP)测定条件及共存物影响。在以 KI为重原子微扰剂、Na2 SO3为除氧剂及 λex/λem=31 7/5 1 8nm的最佳组合条件下 ,测定 NNA的线性范围及检出限分别为 1 .4× 1 0 - 7～ 2 .5× 1 0 - 5mol/L及1 .2× 1 0 - 8mol/L。方法已用于江水及井水样品中 NNA的测定 ,回收率 98.2 %～1 0 1 .9%,相对标准偏差 1 .2 %～ 1 .3%。     

纸基质室温燐光法测定痕量6-苄氨基嘌呤的研究

本文经实验发现6-苄氨基嘌呤吸附在滤纸基质上能够发射出室温燐光。较详细地研究了其室温燐光特性。实验表明,在弱碱性条件下,以KI-NaAc作混合重原子微扰剂时,6-苄氨基嘌呤能产生较强的燐光发射,在此条件下,6-苄氨基嘌呤浓度与室温燐光发射强度之间在1×10~(-5)～9×10~(-4)mol/L范围内呈良好的线性关系。检出限为8ng/斑点。     

4-溴联苯的无保护性介质流体室温燐光和延迟荧光性质研究

发现４－溴联苯在无保护性介质存在且不需除氧的条件下即有一定强度的流体室温燐光和延迟荧光发射。借助于少量有机溶剂的增溶作用和除氧操作，可以获得完全清澈透明的延迟荧光测量体系，溴联苯的检出限为１．５×１０－６ｍｏｌ／Ｌ。     

吲哚在无保护溶液体系中的室温燐光

本文研究了吲哚的无保护流体室温燐光(NP-RTP)性质。基于NP-RTP建立起来的分析方法已直接用于鱼中吲哚的测定。方法的线性范围为1.0×10-7~7.0×10-6mol/L,相对标准偏差为2.1%~3.4%。本方法无须保护性介质而仅以KI为重原子微扰剂、Na2SO3为除氧剂即可。0.60 mol/L KI、2.0×10-3mol/L Na2SO3和pH 8.6为方法的最佳测定条件。     

胶束增稳室温燐光法中化学除氧技术的研究

简便、快速的Na_2SO_3化学除氧技术改善了胶束增稳室温燐光法(MS-RTP)通氮除氧过程费时、繁冗的操作。本文对化学除氧MS-RTP的各种影响条件做了较详细的研究。实验表明,除了SDS、TINO_3、Na_2SO_3用量及温度等因素外,pH对RTP强度和除氧时间也有显著的影响。本文对前人工作作了补充和完善,并对化学除氧机理提出了不同的认识。文中对国产SDS进行了提纯。在荧光光度计上建立了化学除氧MS-RTP法。     

罗丹明和荧光素类染料的固体基质室温燐光研究

研究了13种吨染料在滤纸基质上的室温燐光（RTP）性质。发现具有重原子取代基的荧光素本身能有较强的RTP发射。若以Ph（AC）2为重原子微扰剂，则所有染料均能产生不同强度的RTP信号。探讨了取代基对RTP发射的影响，测定了它们的RTP寿命。     

胶束介质中萘敏化双乙酰的室温磷光

研究了ＳＤＳ胶束介质中萘敏化双乙酰有室温磷光，认为ＳＤＳ增加了萘与乙酰的能量转移效率，敏化磷光强度与Ｐｏｉｓｓｏｎ分布有关，并由胶团中含较少给（受）体的Ｐｉ３ｓａ＾Ａ×Ｐｌｅｓｓ＾Ｄ决定。选择了最佳实验条件，该法简便、快速、萘的检出限达６．５×１０＾－８ｍｏｌ／Ｌ。     

隐丹参酮和丹参酮IIA滤纸基质室温磷光法的研究

考察了隐丹参酮和丹参酮 IIA的滤纸基质室温磷光法 ( PS- RTP)特性。选择Cd( Ac) 2 作为重原子微扰剂 ,对影响这两种丹参酮类化合物发光强度的各种因素进行了详细研究。同时建立了隐丹参酮和丹参酮 IIA的 PS- RTP分析测定的新方法     

Room-Temperature Phosphorescence from a Series of 3-Pyridylcarbazole Derivatives

Exploration of pure metal-free organic molecules that exhibit strong room-temperature phosphorescence (RTP) is an emerging research topic. In this regard, unveiling the design principles for an efficient RTP molecule is an essential, but challenging, task. A small molecule is an ideal platform to precisely understand the fundamental role of each functional component because the parent molecule can be easily derivatized. Here, the RTP behaviors of a series of 3-pyridylcarbazole derivatives are presented. Experimental studies in combination with theoretical calculations reveal the crucial role of the n orbital on the central pyridine ring in the dramatic enhancement of the intersystem crossing between the charge-transfer-excited singlet state and the locally excited triplet states. Single-crystal X-ray crystallographic studies apparently indicate that both the pyridine ring and fluorine atom contribute to the enhancement of the RTP because of the restricted motion owing to weak C−H⋅⋅⋅N and H⋅⋅⋅F hydrogen-bonding interactions. The single crystal of the fluorine-substituted derivative shows an ultra-long phosphorescent lifetime (τ_P) of 1.1 s and a phosphorescence quantum yield (Φ_P) of 1.2 %, whereas the bromine-substituted derivative exhibits τ_P of 0.15 s with a Φ_P of 7.9 %. We believe that this work provides a fundamental and universal guideline for the generation of pure organic molecules exhibiting strong RTP.     

Crystallization-Enhanced Emission and Room-Temperature Phosphorescence of Cyclic Triimidazole-Monohexyl Thiophene Derivatives

The development of organic room-temperature phosphorescent (ORTP) materials represents an active field of research due to their significant advantages with respect to their organometallic counterparts. Two cyclic triimidazole (TT) derivatives bearing one and three hexyl-thiophene moieties, TT-HThio and TT-(HThio)₃, have been prepared and characterized. Both compounds display enhanced quantum yields in their crystalline form with respect to those in a solution state, revealing crystallization-enhanced emissive (CEE) behavior. Importantly, while single fluorescence is observed in solution, crystalline powders also feature dual ORTP, whose respective molecular and aggregate origins have been disclosed through X-ray diffraction analysis and DFT/TDDFT calculations. The relation between the photophysical properties of TT-HThio and its crystallinity degree has been confirmed by a decrease in photoluminescent quantum yield (Φ) and loss of vibronic resolution when its crystals are ground in a mortar, revealing mechanochromic behavior and confirming CEE features.     

Enhanced Room-Temperature Phosphorescence through Intermolecular Halogen/Hydrogen Bonding

Room-temperature phosphorescence (RTP) materials with high efficiency have attracted much attention because they have unique characteristics that cannot be realized in conventional fluorescent materials. Unfortunately, efficient RTP in metal-free organic materials is very rare and it has traditionally been considered as the feature to divide purely organic compounds from organometallic and inorganic compounds. There has been increasing research interest in the design and preparation of metal-free organic RTP materials in recent years. It has been reported that intermolecular interactions make a big difference to the photophysical behavior of organic molecules. In this regard, herein, the parameters that affect RTP efficiency are discussed, and a brief review of recent intermolecular halogen-/hydrogen-bonding strategies for efficient RTP in metal-free organic materials are provided. The opportunities and challenges are finally elaborated in the hope of guiding promising directions for the design and application of RTP materials.