Na Sa, Shanzhi Qu, Jinfeng Xu, Kaiqi Nie, Jia-Ou Wang, Junyong Kang, Jin-Cheng Zheng, Meng Wu, Shengli Huang, Hui-Qiong Wang
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引用次数: 0
Abstract
Ionic liquid gating (ILG) is an emergent technique for controlling multiple types of ionic doping and leads to numerous attractive physical properties in quantum materials. This study widens its intriguing applications in metal-free graphitic carbon nitride (g-C3N4) semiconductor which is distinct by various extrinsic defects (vacancies, interlayer defects, etc) and intrinsic defects (irregular melon chains, dangling bonds, etc.). Here, the efficient passivation of defects is realized in g-C3N4through combined electrostatic and electrochemical mechanisms. By optimizing the ionic liquid concentration and applying a negative electric field, the gated g-C3N4exhibit a changed local bonding environment, an increased bandgap, as well as a suppression of photoluminescence (PL) intensity over 80%. Our results demonstrate that the charged ions from the mixed electrolyte passivate the charged defect centers, redistribute the charges within the g-C3N4framework, leading to the improved photogenerated carries separation, which is verified by the enhanced photocatalytic efficiency of treated g-C3N4. In particular, the changes of the density of states near the Fermi level reflect ionic interaction induced defect passivation in g-C3N4, which plays a key role in regulating its PL properties. These findings provide novel insights in ILG mechanisms in layered porous materials and shed light on its potential prospects in other semiconductors with controlled defect engineering.
期刊介绍:
Journal of Physics: Condensed Matter covers the whole of condensed matter physics including soft condensed matter and nanostructures. Papers may report experimental, theoretical and simulation studies. Note that papers must contain fundamental condensed matter science: papers reporting methods of materials preparation or properties of materials without novel condensed matter content will not be accepted.