Tuning the Photoresponse of Nano‐Heterojunction: Pressure‐Induced Inverse Photoconductance in Functionalized WO3 Nanocuboids

Advanced Science

Hajra Saqib¹  Saqib Rahman¹  Lin Wang¹  Sudeshna Samanta¹  Daniel Errandonea²  Junling Lu³  Jaeyong Kim⁴  Alexei Kuzmin⁵  Dale L. Brewe⁶ 

[1] Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China;Departamento de Física Aplicada‐ICMUV MALTA Consolider Team Universidad de Valencia Edificio de Investigación C/Dr. Moliner 50 Burjassot 46100 Valencia Spain;Department of Chemical Physics University of Science and Technology of China Hefei 230026 China;HYU‐HPSTAR‐CIS High Pressure Research Center Department of Physics Hanyang University Seoul 04763 Republic of Korea;Institute of Solid State Physics University of Latvia Kengaraga street 8 LV‐1063 Riga Latvia;X‐Ray Science Division Advanced Photon Source Argonne National Laboratory 9700 South Cass Avenue Argonne IL 60439 USA;

关键词: charge carriers;    compression;    decompression;    inverse photoconductivity;    nano‐heterojunctions;    phase transition;   

DOI  :  10.1002/advs.201901132

来源: DOAJ

【 摘 要 】

Abstract Inverse photoconductivity (IPC) is a unique photoresponse behavior that exists in few photoconductors in which electrical conductivity decreases with irradiation, and has great potential applications in the development of photonic devices and nonvolatile memories with low power consumption. However, it is still challenging to design and achieve IPC in most materials of interest. In this study, pressure‐driven photoconductivity is investigated in n‐type WO3 nanocuboids functionalized with p‐type CuO nanoparticles under visible illumination and an interesting pressure‐induced IPC accompanying a structural phase transition is found. Native and structural distortion induced oxygen vacancies assist the charge carrier trapping and favor the persistent positive photoconductivity beyond 6.4 GPa. The change in photoconductivity is mainly related to a phase transition and the associated changes in the bandgap, the trapping of charge carriers, the WO6 octahedral distortion, and the electron–hole pair recombination process. A unique reversible transition from positive to inverse photoconductivity is observed during compression and decompression. The origin of the IPC is intimately connected to the depletion of the conduction channels by electron trapping and the chromic property of WO3. This synergistic rationale may afford a simple and powerful method to improve the optomechanical performance of any hybrid material.

【 授权许可】

Unknown