摘要
The long-standing challenge in designing far-infrared transparent conductors(FIRTC)is the combination of high plasma absorption edge(λ_(p))and high conductivity(σ).These competing requirements are commonly met by tuning carrier concentration or/and effective carrier mass in a metal oxide/oxonate with low optical dielectric constant(ε_(opt)=2-7).However,despite the highσ,the transparent band is limited to mid-infrared(λ_(p)<5μm).In this paper,we break the trade-off between highσandλ_(p)by increasing the“so-called constant”ε_(opt)that has been neglected,and successfully develop the material family of FIRTC withε_(opt)>15 andλ_(p)>15μm.These FIRTC crystals are mainly octahedrally-coordinated heavy-metal chalcogenides and their solid solutions with shallow-level defects.Their highε_(opt)relies on the formation of electron-deficiency multicenter bonds resulting in the great electron-polarization effect.The new FIRTC enables us to develop the first“continuous film”type far-infrared electromagnetic shielder that is unattainable using traditional materials.Therefore,this study may inaugurate a new era in far-infrared optoelectronics.
基金
The authors gratefully acknowledge the financial support from National Natural Science Foundation of China(Grant Nos.52032004,52272153)
KLOMT Key Laboratory Open Project(2022KLOMT02-05).
