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Zhu J, Shen F, Chen Z, Liu F, Jin S, Lei D, Xu J. Deterministic Areal Enhancement of Interlayer Exciton Emission by a Plasmonic Lattice on Mirror. ACS NANO 2024; 18:13599-13606. [PMID: 38742607 PMCID: PMC11140836 DOI: 10.1021/acsnano.4c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/16/2024] [Accepted: 04/26/2024] [Indexed: 05/16/2024]
Abstract
The emergence of interlayer excitons (IX) in atomically thin heterostructures of transition metal dichalcogenides (TMDCs) has drawn great attention due to their unique and exotic optical and optoelectronic properties. Because of the spatially indirect nature of IX, its oscillator strength is 2 orders of magnitude smaller than that of the intralayer excitons, resulting in a relatively low photoluminescence (PL) efficiency. Here, we achieve the PL enhancement of IX by more than 2 orders of magnitude across the entire heterostructure area with a plasmonic lattice on mirror (PLoM) structure. The significant PL enhancement mainly arises from resonant coupling between the amplified electric field strength within the PLoM gap and the out-of-plane dipole moment of IX excitons, increasing the emission efficiency by a factor of around 47.5 through the Purcell effect. This mechanism is further verified by detuning the PLoM resonance frequency with respect to the IX emission energy, which is consistent with our theoretical model. Moreover, our simulation results reveal that the PLoM structure greatly alters the far-field radiation of the IX excitons preferentially to the surface normal direction, which increases the collection efficiency by a factor of around 10. Our work provides a reliable and universal method to enhance and manipulate the emission properties of the out-of-plane excitons in a deterministic way and holds great promise for boosting the development of photoelectronic devices based on the IX excitons.
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Affiliation(s)
- Jiasen Zhu
- Department
of Electronic Engineering, The Chinese University
of Hong Kong, Shatin 999077, Hong Kong SAR, China
| | - Fuhuan Shen
- Department
of Electronic Engineering, The Chinese University
of Hong Kong, Shatin 999077, Hong Kong SAR, China
| | - Zefeng Chen
- School
of Optoelectronic Science and Engineering and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
| | - Feihong Liu
- Department
of Materials Science and Engineering, City
University of Hong Kong, Kowloon 999077, Hong Kong SAR, China
| | - Shuaiyu Jin
- Department
of Materials Science and Engineering, City
University of Hong Kong, Kowloon 999077, Hong Kong SAR, China
| | - Dangyuan Lei
- Department
of Materials Science and Engineering, City
University of Hong Kong, Kowloon 999077, Hong Kong SAR, China
| | - Jianbin Xu
- Department
of Electronic Engineering, The Chinese University
of Hong Kong, Shatin 999077, Hong Kong SAR, China
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Xiong Y, Chikkaraddy R, Readman C, Hu S, Xiong K, Peng J, Lin Q, Baumberg JJ. Metal to insulator transition for conducting polymers in plasmonic nanogaps. LIGHT, SCIENCE & APPLICATIONS 2024; 13:3. [PMID: 38161207 PMCID: PMC10757999 DOI: 10.1038/s41377-023-01344-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/17/2023] [Accepted: 11/22/2023] [Indexed: 01/03/2024]
Abstract
Conjugated polymers are promising material candidates for many future applications in flexible displays, organic circuits, and sensors. Their performance is strongly affected by their structural conformation including both electrical and optical anisotropy. Particularly for thin layers or close to crucial interfaces, there are few methods to track their organization and functional behaviors. Here we present a platform based on plasmonic nanogaps that can assess the chemical structure and orientation of conjugated polymers down to sub-10 nm thickness using light. We focus on a representative conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), of varying thickness (2-20 nm) while it undergoes redox in situ. This allows dynamic switching of the plasmonic gap spacer through a metal-insulator transition. Both dark-field (DF) and surface-enhanced Raman scattering (SERS) spectra track the optical anisotropy and orientation of polymer chains close to a metallic interface. Moreover, we demonstrate how this influences both optical and redox switching for nanothick PEDOT devices.
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Affiliation(s)
- Yuling Xiong
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Rohit Chikkaraddy
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
- School of Physics & Astronomy, University of Birmingham, Edgbaston, Birmingham, UK
| | - Charlie Readman
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Shu Hu
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Kunli Xiong
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Jialong Peng
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
- College of Advanced Interdisciplinary Studies and Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, China
| | - Qianqi Lin
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
- Hybrid Materials for Opto-Electronics Group, Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Center and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, Enschede, Netherlands
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK.
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