Conformation-dependent dynamic organic phosphorescence through thermal energy driven molecular rotations

Abstract

Organic room-temperature phosphorescent (RTP) materials exhibiting reversible changes in optical properties upon exposure to external stimuli have shown great potential in diverse optoelectronic fields. Particularly, dynamic manipulation of response behaviors for such materials is of fundamental significance, but it remains a formidable challenge. Herein, a series of RTP polymers were prepared by incorporating phosphorescent rotors into polymer backbone, and these materials show color-tunable persistent luminescence upon excitation at different wavelengths. Experimental results and theoretical calculations revealed that the various molecular conformations of monomers are responsible for the excitation wavelength-dependent (Ex-De) RTP behavior. Impressively, after gaining insights into the underlying mechanism, dynamic control of Ex-De RTP behavior was achieved through thermal energy driven molecular rotations of monomers. Eventually, we demonstrate the practical applications of these amorphous polymers in anti-counterfeiting areas. These findings open new opportunities for the control of response behaviors of smart-responsive RTP materials through external stimuli rather than conventional covalent modification method.

Recent Advances of Pure Organic Room Temperature Phosphorescence Based on Functional Polymers

“…The molecular conformation of luminophore may be changed by a rigid environment. Thus, various twisted conformations can cause continuous changes in RTP wavelength with the excitation wavelength . The use of multiple luminophores to prepare codoped RTP systems by Li et al also obtained excitation wavelength-dependent RTP (Figure ).…”

“…Thus, various twisted conformations can cause continuous changes in RTP wavelength with the excitation wavelength. 52 The use of multiple luminophores to prepare codoped RTP systems by Li et al 53 also obtained excitation wavelength-dependent RTP (Figure 8). And this method introduced is controllable compared to unquantifiable aggregates.…”

Photo-activated time-dependent color-changeable ultralong organic room temperature phosphorescence by co-doping strategy

“…Ultralong organic room temperature phosphorescence (UORTP) is a hot topic [1][2][3][4][5][6] and has wide application potential in health monitoring, [7][8][9] light-emitting devices, [10][11][12] anti-counterfeiting [13][14][15][16] and information encryption, [17][18][19][20] due to the long-lived characteristics of phosphorescence and easy modification of organic molecules. [21][22][23][24] Since the discovery of H-benzo[f]indole (Bd, a carbazole isomer) in carbazole-based phosphorescence systems, 25,26 guest-matrix doping has become a popular strategy to construct UORTP materials.…”

A Dual‐Responsive Liquid Crystal Elastomer for Multi‐Level Encryption and Transient Information Display

“…With the booming of the Internet of Things (IoT) and 5G wireless communications technology, information security becomes more and more important, promoting the development of responsive materials and technologies for encryption, anti-counterfeiting, and secure storage of information. In recent years, tremendous efforts have been made to develop advanced anti-counterfeiting materials and corresponding encryption techniques, including photonic crystals, [1][2][3][4][5] structural-color materials, [6][7][8] rewritable materials, [9][10][11] wrinkles, [12][13][14] watermarks, [15] holograms, [16] and fluorescent/phosphorescent imaging, [17][18][19][20] etc, to avoid the threat of false information and information leakage. By combining multiple anti-counterfeiting techniques or multiple stimuli (such as light, temperature, pH, and moisture) that trigger decryption, the information is thus made more difficult to copy, enhancing the security level.…”