Research group of Xu Bingjia, associate researcher of South China Normal University: pure organic aggregation induced force induced ultra long room temperature phosphorescence and photoluminescence trichromatic conversion of white materials

Mechanical luminescence (ML) refers to the phenomenon that materials directly produce light emission under the action of external forces (such as compression, stretching, bending, cutting, grinding, vibration, scraping, etc.), which is different from the common photoluminescence and electroluminescence The long-term afterglow with the name of "night pearl" refers to the phenomenon that the luminescence of materials is still continuing after the excitation source is removed It is usually formed by ultra long room temperature phosphorescence emission In the past, the long afterglow of pure organic materials was triggered by light or electricity, which limited its application to a large extent Recently, Xu Bingjia, an associate researcher of South China Normal University, has made important progress in the field of organic electroluminescent materials and developed pure organic white light materials that can generate afterglow through force triggering Relevant work was published in angelw Chem Int ed (DOI: 10.1002 / ange 201800762) Brief introduction of Xu Bingjia's research group Xu Bingjia, deputy researcher, was founded in March 2017, relying on the Key Laboratory of the Ministry of environmental theory and chemistry of South China Normal University and the Institute of materials science and engineering His main research fields are: 1) synthesis, performance and exploration of light-emitting or light-emitting color changing mechanism of new force stimulated response organic light-emitting materials; 2) synthesis and localization of organic / polymer photoelectric response functional materials Applications in sensing, OLED and biomedical imaging and therapy Xu Bingjia, associate researcher, School of chemistry and environment, South China Normal University Graduated from the school of chemistry and chemical engineering of Sun Yat sen University in June 2008, with a bachelor's degree of science; from February 2012 to February 2014, he was supported by the national fund for studying abroad to carry out joint training of doctoral students in the Department of chemistry and Biomolecular Engineering of UCLA, under the guidance of Professor Lu Yunfeng; in June 2014, he graduated from the school of chemistry and chemical engineering of Sun Yat sen University, with a master's degree in engineering His tutors are Professor Xu Jiarui and Professor Chi Zhenguo; from August 2014 to November 2016, he worked in the optical engineering mobile station of Sun Yat sen University for postdoctoral research (special grant type), and his co tutor is Professor Jin chongjun Since October 2016, he has been an associate researcher of the school of chemistry and environment of South China Normal University, and the "top young" talents of South China Normal University So far, more than 40 SCI papers have been published Among them, as the first author and corresponding author, I worked in angelw Chem Int ed., chem SCI, More than 10 papers have been published in the top journals of SCI area I in chemistry field such as chem.commun., including 2 papers reported by chemistviews.org as research highlights, 2 papers highly cited by ESI, and 1 paper among the top 10 papers downloaded by chem.sci quarterly The first author and corresponding author's papers have been cited by SCI for more than 500 times At present, he has presided over many projects, such as the National Natural Science Foundation, major scientific research projects of Guangdong universities, Guangzhou Science and technology plan, etc He has been selected as a young Pearl River scholar in Guangdong Province and a new star of Pearl River science and technology in Guangzhou Leading edge scientific research achievements: pure organic aggregation induces the forced ultra long room temperature phosphorescence emission of white light materials and the conversion of light-induced trichromatic emission The forced light-emitting materials refer to a kind of solid materials that can directly generate light emission under the external force, which have important potential applications in display, lighting, stress sensing, security and anti-counterfeiting fields However, the traditional organic materials in the solid state will occur aggregation concentration quenching (ACQ), resulting in the weak and even difficult to observe the electroluminescence at room temperature From 2015 to 2016, Dr Xu Bingjia, Professor Chi Zhenguo, Professor Zhang Yi and Professor Xu Jiarui of Sun Yat sen University, through a series of comparative studies, found that the large transition dipole moment of polar molecules and the aggregation induced emission of molecules in the noncentrally symmetric crystal structure, AIE) effect has a significant enhancement effect on the electroluminescence of organic materials, providing direction and effective strategies for molecular design of such materials (chem SCI., 2015, 6, 3236; chem SCI., 2016, 7, 5307) In recent two or three years, many important progresses have been made in the field of organic electroluminescence in the world, and some high brightness organic electroluminescent materials with aggregation induced luminescence properties have been developed However, there is no report on the study of long afterglow organic materials In the past, the long afterglow of pure organic materials was triggered by light or electricity, and its application range was limited to a great extent Fig 1 Photoluminescence conversion of compounds (source: angelw Chem Int ed.) recently, Xu Bingjia, an associate researcher, worked with the research group on organic electroluminescent materials, organic single molecule white light materials (chem SCI., 2016, 7, 2201) and instantaneous fluorescence room temperature phosphorescence double emission organic materials (chem SCI., 2017, 8, 1909), etc In cooperation with Professor Shi Guang, a pure organic white light compound IMBR with the properties of "aggregation induced luminescence" and "instantaneous fluorescence room temperature phosphorescence double emission" was synthesized by introducing halogen substituted bromine into N - (4-trifluoromethylphenyl) phthalimide It is found that the crystal powder of the compound can emit strong blue light under the action of external force, and yellow ultra long room temperature phosphorescence can still be observed when the external force disappears, which shows the characteristics of persistent room temperature mechanism The research results not only change the current situation that the long-term afterglow of pure organic materials can only be triggered by light or electricity, but also make the research of organic electroluminescence take an important step forward, creating a broader space for the application of long-term afterglow materials and organic electroluminescence materials At the same time, under the irradiation of UV lamp, the light-emitting color of the material can change from blue to white; after the UV lamp is removed, the light-emitting color of the material changes from white to yellow In other words, by simply turning on and off the UV lamp, the luminous color of the material can be reversed between blue, white and yellow, which has important potential applications in security, anti-counterfeiting, information storage and other fields The results of single crystal structure analysis and quantum chemistry calculation show that the mechanism of the long afterglow of the compound IMBR is related to the strong spin orbit coupling of the bromine atom in the molecule, the formation of the H-aggregate in the asymmetric crystal structure and the restriction of the intramolecular motion In addition, the preliminary molecular design strategy of this kind of materials is put forward through comparative study, which provides a theoretical basis for the follow-up study Fig 2 The force-induced ultra long room temperature phosphorescence emission of compounds and its possible formation mechanism (source: angelw Chem Int ed.) related results were recently published on angelw Chem Int ed., associate researcher Xu Bingjia and Professor Shi Guang were co correspondents of the paper, and undergraduate students li Jian'an and Zhou Jinghong were co first authors of the paper The research work was supported by the National Natural Science Foundation of China, Guangzhou Science and technology plan, Guangdong University's major scientific research special characteristic innovation project, Guangdong Natural Science Fund and the "young top" talent introduction start-up fund of South China Normal University Chemistviews.org, an international well-known academic website, also reported the work as a highlight Corresponding author: Professor Shi Guang, associate researcher Xu Bingjia, said that people and scientific research are increasingly valued in the economic life of scientific and technological elements Today, China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeango app, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.