Radical Hybrids with Multiple Responses to Thermal Stimuli via Electron Transfer

• Published in: Advanced functional materials 2022-09, Vol.32 (39), p.n/a
• Main Authors: Sang, Yu‐Feng, Zeng, Hao, Xu, Liang‐Jin, Chen, Zhong‐Ning
• Format: Article
• Language: English
• Subjects: Cations; Chains; Circuits; Color; conductivities; Electrical resistivity; Electron paramagnetic resonance; Electron transfer; Electronic devices; Electrons; Heat conductivity; Heat transfer; hybrid; Materials science; Modular design; Photoelectrons; radicals; Stimuli; Temperature dependence; Thermal conductivity; thermochromism
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202206459

It is desirable to develop semiconductors with simultaneously multiple responses to single stimuli. Herein, a thermally responsive hybrid semiconductor (AEV)[Pb2Br8] (AEV4+ = 1,1′‐bis(2‐ammonioethyl)‐[4,4′‐ bipyridine]‐1,1′‐diium) is successfully prepared by introducing functionalized organic cations into 1D lead(II) chains. The lead(II) chain contains an edge‐sharing PbBr6 octahedron with highly electron‐deficient cations distributed in the interspace of the inorganic framework. Interestingly, the as‐formed hybrid exhibits extraordinary thermochromic behavior along with intriguing temperature‐dependent conductivity and thermal conductivity due to the thermal motion of the electrons in the hybrid. Specifically, the color of the pristine hybrid changes from yellow to brown when the temperature rises to 70 °C, and gradually deepens as the temperature continues to rise, accompanied by the continuous decline in electric conductivity and thermal conductivity. Once heating is stopped, the color and conductivity recover to the original state in a few minutes. As demonstrated by electron paramagnetic resonance and X‐ray photoelectron spectroscopy studies, the thermal‐induced electron transfer is likely responsible for the intriguing thermally responsive behaviors. This work provides a paradigm for the modular and functional design of hybrid materials that manifest potential applications in semiconductor refrigeration, thermal power generation, intelligent circuit, and other opt‐electronic devices. A 1D organic–inorganic hybrid material (AEV)[Pb2Br8] with multiple responses to thermal stimuli is obtained by reacting viologen derivative with PbBr2, the as‐formed hybrid displays strong electron paramagnetic resonance signal at room temperature and exhibits significant thermochromic behavior along with intriguing conductivity and thermal conductivity with various temperature due to the thermal motion of electrons in the hybrids.