Stimuli‐responsive photofunctional materials for green and security printing

Abstract

Information recording on paper has always been the most important approach to keep records of human activity and to spread civilization. With the progress of science and technology, paper with different functions should be exploited to conform to the increasing demands in various scenarios. In one aspect, traditional paper can only be used once, and using large amounts of paper causes deforestation, additional solid waste treatment, environmental pollution, and high energy consumption. Consequently, the development of rewritable paper that is environment-friendly, low cost, and can save resources is significant for green printing. In the other aspect, information leakage brings security issues, which may lead to severe consequences, such as war outbreak, economic loss, social problems, and so on. Therefore, the development of security printing has also attracted wide interests. Stimuli-responsive photofunctional materials that have reversible variations in absorption or emission in response to changes in the external environmental have a great potential for the achievement of green and security printing. To date, much progress has been made in these research areas. This paper lists different smart materials that respond to various external stimuli, such as light, water, pH, heat, and metal ions, and summarizes the recent advances towards green and security printing. Also, we discuss the current challenges and future directions in this rapidly growing research field. It is expected that this review article will stimulate and guide future studies for the advanced green and security printing.

Color‐Tunable Dual Persistent Emission Via a Triplet Exciton Reservoir for Temperature Sensing and Anti‐Counterfeiting

“…Considering the variable persistent emission at different temperature, these materials were used to monitor temperature changes in a wide range. [21] As shown in Figure 5a, a commercially available ultraviolet LED is coated with a mixture of Ph-C8Br solid and Aloe vera gel. The changed afterglow color can be observed at various temperatures after removing power supply.…”

Reversible On–Off Switching of Excitation-Wavelength-Dependent Emission of a Phosphorescent Soft Salt Based on Platinum(II) Complexes

“…Under different external stimuli, such as light, − mechanical force, − vapor, − electric field, − or temperature, − materials that can exhibit a reversible change in their optical properties have huge application potentials within various optoelectronic fields. Among these types of optical materials, excitation-wavelength-dependent (Ex-De) luminophores have attracted particular interest. − This is due to the facile, fast, and noninvasive manipulation of their luminescence color by varying the excitation energy; such systems demonstrate great promise in bioimaging and anticounterfeiting applications .…”

Mechanoluminescent hybrids from a natural resource for energy‐related applications

“…Stimuli-responsive materials (SRMs), whose characteristics can be switched using an external stimulus such as electricity, light, heat, and mechanical energy, underpin emerging technologies ranging from sensors, actuators, generators, to energy harvesters. 1,2 In particular, as a class of SRMs with a long history, inorganic mechanoluminescent (ML) materials that can repeatedly convert mechanical energy into photon emission with excellent performances have been re-emerging for their potential applications in sensing, [3][4][5][6] displays, [7][8][9][10][11][12] and as special light sources. 13,14 During the last decade, many endeavors have been dedicated to the development of new ML materials with different lanthanide ions paired with different substrates for realizing versatile ML emissions.…”