Reversible Multilevel Stimuli‐Responsiveness and Multicolor Room‐Temperature Phosphorescence Emission Based on a Single‐Component System

Abstract

There are limited reports about the transformation of pure organic room-temperature phosphorescence (RTP) materials with multilevel stimuli-responsiveness at different RTP emission wavelengths under external stimuli. It is difficult to ensure efficient intersystem crossing (ISC) in different states of a singlecomponent system. This research reports the conversion of the organic single-component small molecule 1,2bis(4-alkoxyphenyl)ethane-1,2-dione (N-BOX) with multilevel stimuli-responsiveness between high-efficiency blue and yellow RTP by grinding or thermal annealing N-BOX crystals. The RTP emission of N-BOX in the crystalline state was easy to adjust by external stimuli (grinding or thermal annealing) due to its non-compact packing, which led to a phase transition and generated unique multilevel stimuli-responsiveness. In particular, the RTP quantum yield of 7-BOX with multilevel stimuli-responsiveness reached 68.4 %, which provides an opportunity for regulation of smart optical materials based on pure organic RTP.

A Mild‐Stimuli‐Responsive Fluorescent Molecular System Enables Multilevel Anti‐Counterfeiting and Highly Adaptable Temperature Monitoring

“…1 H NMR (600 MHz, DMSO-d 6 , 298 K, δ): 10.71 (s, 1H), 8.95 (d, J = 8.6 Hz, 1H), 8.45 (d, J = 7.2 Hz, 1H), 8.11 (s, 1H), 8.06 (t, J = 7.8 Hz, 1H), 7.88 (t, J = 7.9 Hz, 1H), 7.81 (d, J = 6.1 Hz, 1H), 7.76 (d, J = 8.6 Hz, 1H), 7.19-7.15 (m, 5H), 7.10 (t, J = 7.2 Hz, 2H), 7.05 (d, J = 7.5 Hz, 4H), 3.97 (t, J = 7.2 Hz 2H), 1.59-1.54 (m, 2H), 1.35-1.28 (m, 2H), 0.90 (t, J = 7.4 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 , 298 K, δ): 164. 16, 163.83, 150.63, 143.62, 141.90, 139.12, 138.21, 133.78, 130.12, 128.01, 127.86, 127.74, 126.33, 125.79, 122.66, 119.59, 117.56, 115.81, 115.37, 55.37, 30.21, 20.30, 14.16 Construction of Mild-Stimuli-Responsive Fluorescent Molecular Systems: Two kinds of mild-stimuli-responsive fluorescent systems were constructed in solution and film state of the NI-CBN, respectively.…”

“…Over the last few decades, organic luminescent materials with responses to one or more external “triggers,” such as light, [ 11,12 ] heat, [ 13,14 ] mechanical force [ 15,16 ] and chemical vapors, [ 17,18 ] have gained increasing attention owing to their potentials for a variety of applications. [ 19 ] The feature of adjustable fluorescence color changes on demand endows the smart materials with an encoding capacity, as well as an easily decodable property through visualized patterns.…”

“…[5][6][7] Compared to conventional physical (e.g., mercury, ethanol) and electronic (e.g., thermocouple) thermometers, luminescence thermometers possess distinct merits of visualization, non-invasiveness, fast response, and particularly can work in an electromagnetic circumstance, and provide high spatial and thermal resolutions. [8][9][10] Over the last few decades, organic luminescent materials with responses to one or more external "triggers," such as light, [11,12] heat, [13,14] mechanical force [15,16] and chemical vapors, [17,18] have gained increasing attention owing to their potentials for a variety of applications. [19] The feature of adjustable fluorescence color changes on demand endows the smart materials with an encoding capacity, as well as an easily decodable property through visualized patterns.…”

Recent Advances in Mechano-responsive Fluorescent Organic and Organometallic Compounds: Structural Diversity, Phase Transformation and Applications

“…Phase conversion from the crystalline to the amorphous states is one of the most common transformations that occur as a result of mechano-responsive fluorescent compounds being subjected to a mechanical stimulus. [74][75][76][77] The said transformation contributed to MCL accompanied by structural variation of solvent exclusion, intermolecular interactions transformation, conformational fluctuations, and so on.…”

Dual Guests Synergistically Tune the Phosphorescence Properties of Doped Systems through Chemical Interactions with Bases

“…Organic room temperature phosphorescence (RTP) materials with a long afterglow property have unique advantages in anticounterfeiting, biological diagnosis and treatment, and optoelectronic devices. − Intersystem crossing (ISC) of excitons and stable triplet excitons are prerequisites for organic materials to exhibit phosphorescence. − Early organic RTP materials were mainly single-component compounds; the researchers increased the ISC ability of excitons by introducing carbonyl groups or halogen atoms into the molecules or designing donor–acceptor type molecular configurations. ,− As an emerging technology in recent years, people have found that guest–host doped strategy can cause the doped materials to have RTP activity, which has attracted widespread attention. − The host matrix can help the energy transfer of guest excitons, and the rigid structure of the host can effectively limit the motion of the guests, thereby stabilizing the triplet excitons. − However, despite the rapid development of doped RTP materials, these systems are basically two-component systems, which are often limited by low performance and limited functionality.…”