Dr. Zhang hanyue of Southeast University published the latest research results of metal organic semiconductor ferrite in the Journal of American Chemical Society

Recently, Zhang hanyue, Ph.D student of International Institute of molecular ferroelectric science and application and Jiangsu Provincial Key Laboratory of molecular ferroelectric science and application, School of chemistry and chemical engineering, Southeast University, published "narrow band gapobserved in a molecular ferroelectric: ferrocenium" on the top journal of the American Chemical Society (Journal of the American Chemical Society) Academic paper of tetrachloroferrate (DOI: 10.1021 / JACS 9b13446) This study is the first to report the ferrocenium tetrachloroferrate, [Fe (CP) 2] [FeCl 4] with narrow band gap (1.61 EV) and high phase transition temperature (407.7 K) This research will stimulate people's interest in the further research of metal organic ferroelastic materials, and point out the direction for the potential application of metal organic ferroelastic materials in optoelectronic devices As one of the three main ferrous materials, ferrite has laid a foundation for the research of multiferrous materials At the same time, the great contributions of multifunctional coupling in the fields of nano transducer, sensor, actuator, solar photovoltaic and non-volatile memory bring endless possibilities for the development of multifunctional coupling materials in the future Fig 1 (a) crystal structure diagram of [Fe (CP) 2] [FeCl 4]; and (b) crystal stacking diagram along the c axis (source: J am Chem SOC.) Fig 2 (a) temperature change PXRD diagram of [Fe (CP) 2] [FeCl 4]; (b) DSC curve; (c) real part curve of dielectric constant at 1MHz frequency with temperature change; (d) UV-Vis absorption spectrum, embedded figure: tauc diagram (source: J am Chem SOC.) in the field of ferroelastic materials, successive researchers have made great contributions, but there are still some areas that have not been fully developed, among which ferroelastic materials with excellent photovoltaic effect are found particularly attractive With the emergence of solar cells based on (ch3nh3) pbi3, the reliable mechanism to explain the high photoelectric conversion efficiency in the organic-inorganic system has been in active debate However, centrone et al attributed it to the ferroelasticity of (ch3nh3) pbi3 and provided reliable experimental evidence In addition, vanadium dioxide (VO 2) is a typical ferroelastic material with narrow band gap semiconductor characteristics There is a reversible transition from monoclinic structure to tetragonal structure in the vicinity of 341k It is worth noting that it is the Elasto-optical effect that makes VO 2 widely concerned in many fields such as fast switching and electrochromism Figure 3 Ferroelastic domain changes during continuous heating and cooling (source: J am Chem SOC.) As a beneficial supplement to inorganic ferrite, molecular ferrite has the advantages of environmental friendliness, easy processing, mechanical flexibility, matching of acoustic impedance with human body and biocompatibility, while outstanding structural controllability also provides an ideal design platform for material performance optimization through molecular modification However, there is still a certain gap in performance between molecular ferrite and inorganic ferrite In view of this, Dr Zhang hanyue, under the guidance of his tutor and through unremitting efforts, has successfully developed the world's first ferrocene Ferrite: [Fe (CP) 2] [FeCl 4], whose band gap is only 1.61 EV, which is significantly lower than many typical undoped ferrite, such as BiFeO 3 (2.7 EV), m-bivo 4 (2.4 EV) and CS 3 Bi 2 I = (2.0 ~ 3.5 EV) And so on In addition, the phase transition temperature of 407.7 K (far beyond 330 K of (ch3nh3) pbi3) further guarantees that it can adapt to a wider application range (Figure 2) The change of ferroelastic domain with temperature can be directly observed by polarizing microscope, which is a direct proof of ferroelasticity of the material (Fig 3) This work shows the great application potential of metal organic ferrite in the new generation of optoelectronic devices The first author of this paper is Zhang hanyue, Ph.D student of School of chemistry and chemical engineering of Southeast University, the corresponding author is Professor Xiong rengen, and Southeast University is the first communication unit The research results are supported by the "top ten scientific and technological issues of Southeast University" start-up cultivation fund.