Key Takeaways & Executive Findings
- •• A flexible dual-mode photodetector array enables simultaneous electrical and optical signal generation for human–machine collaborative infrared imaging. • Geometrically asymmetric electrodes enhance the photothermoelectric responsivity to 0.33 mA W−1, doubling performance compared to symmetric designs. • The device maintains stable performance after 300 bending cycles, demonstrating excellent mechanical flexibility for wearable applications. • Coupling MXene photothermal conversion with thermochromic composites enables real-time visualization of invisible infrared radiation, setting a new benchmark for human–machine collaborative optoelectronics.
Abstract
Photothermoelectric (PTE) photodetectors with self-powered and uncooled advantages have attracted much interest due to the wide application prospects in the military and civilian fields. However, traditional PTE photodetectors lack of mechanical flexibility and cannot operate independently without the test instrument. Herein, we present a flexible PTE photodetector capable of dual-mode output, combining electrical and optical signal generation for enhanced functionality. Using solution processing, high-quality MXene thin films are assembled on asymmetric electrodes as the photosensitive layer. The geometrically asymmetric electrode design significantly enhances the responsivity, achieving 0.33 mA W−1 under infrared illumination, twice that of the symmetrical configuration. This improvement stems from optimized photothermal conversion and an expanded temperature gradient. The PTE device maintains stable performance after 300 bending cycles, demonstrating excellent flexibility. A new energy conversion pathway has been established by coupling the photothermal conversion of MXene with thermochromic composite materials, leading to a real-time visualization of invisible infrared radiation. Leveraging this functionality, we demonstrate the first human–machine collaborative infrared imaging system, wherein the dual-mode photodetector arrays synchronously generate human-readable pattern and machine-readable pattern. Our study not only provides a new solution for functional integration of flexible photodetectors, but also sets a new benchmark for human–machine collaborative optoelectronics.
1. Introduction
Infrared photodetectors are devices that convert incident infrared radiation signals into electrical signals, which have a wide range of applications such as military infrared guidance, security monitoring cameras, and medical thermal imaging diagnosis [1–4]. Infrared photodetectors utilize the physical effects presented by the interaction between infrared radiation and matter to detect the invisible light. According to the working mechanism of the devices, they can be divided into different classes including photoconductive detectors, photovoltaic detectors, quantum well detectors, bolometers, pyroelectric detectors and so on [5–8].
Among numerous infrared detecting mechanisms, the photothermoelectric (PTE) mode photodetectors are a kind of self-powered device that combine photothermal and thermoelectric effects. With the advantages of room temperature operability and low dark current, PTE photodetectors have become a research hotspot in recent years [9–12]. For example, Gong et al. designed a metasurface on a semimetallic Cd3As2 nanoplate to improve its thermoelectric photoresponse, yielding a responsivity of about 1 mA W−1 with the metasurface-enhanced light absorption [13]. Bao et al. developed a phonon-enhanced PTE photodetector with sensitivity up to 1.2 V W−1 and broadband spectral response from 325 nm to 10.67 μm based on reduced STO (SrTiO3-δ) single crystal [14]. Wang and co-workers proposed an infrared PTE photodetector with ultrahigh polarization sensitivity up to 2.5 × 10^4, which was constructed on tellurium nanoribbon and perfect plasmonic absorber [15].
Despite these significant progress, infrared photodetectors based on the principle of PTE effect still have some issues to overcome. Inorganic materials that combine photothermal and thermoelectric effects are usually hard and brittle, lacking mechanical flexibility, which limits the application in flexible electronics and wearable devices. In this situation, there is an urgent need for flexible photodetectors that combine high detection performance and excellent mechanical performance [16–19]. Another drawback is that all photodetectors convert light into electrical signals, and without an electrical signal detection instrument, the device cannot work independently. In the wild or in some emergency situations, there is only a need to quickly and qualitatively determine the presence or absence of infrared radiation. However, the existing photothermoelectric photodetectors lack a convenient and visual recognition mode.
Loading authentic research manuscript (Pages 1–5)...
Huajing Fang, Xinxing Xie, Kai Jing, Shaojie Liu, Ainong Chen, Daixuan Wu, Liyan Zhang, He Tian (2025). A Flexible Dual-Mode Photodetector for Human–Machine Collaborative IR Imaging. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01758-5
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is a dual-mode photodetector?
A dual-mode photodetector is a device that can generate both electrical and optical signals in response to infrared radiation, enabling simultaneous machine-readable and human-readable outputs.
How does the asymmetric electrode design improve performance?
The geometrically asymmetric electrodes enhance the photothermoelectric responsivity by optimizing photothermal conversion and expanding the temperature gradient, achieving a responsivity of 0.33 mA W−1, twice that of symmetric configurations.
What is the role of MXene in this photodetector?
MXene thin films serve as the photosensitive layer, providing efficient photothermal conversion and contributing to the device's flexibility and high performance.
How does the device achieve human–machine collaborative imaging?
The device couples MXene photothermal conversion with thermochromic composites, allowing real-time visualization of infrared radiation (human-readable) while also generating electrical signals (machine-readable), enabling a collaborative imaging system.
What are the potential applications of this technology?
Potential applications include wearable electronics, military infrared guidance, security monitoring, medical thermal imaging, and human–machine collaborative systems where both visual and electronic detection are needed.
Related Technical Papers & Translations
Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration
The rapid accumulation of spent LiFePO4 (LFP) cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies. In this context, direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials, offering a streamlined pathway to restore their electrochemical functionality. We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP. The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode–electrolyte interface, giving a remarkable rate capability with specific capacities of 122 mAh g−1 at 5C and 106 mAh g−1 at 10C (1C = 170 mA g−1). It also maintained capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles. It could be used in harsh environments and could be stably cycled at subzero temperatures (−10 and −20 °C) and in solid-state electrolyte batteries. Life cycle assessment combined with economic evaluation using the EverBatt model reveals that this direct regeneration approach has high economic and environmental benefits.
Oxide Semiconductor for Advanced Memory Architectures: Atomic Layer Deposition, Key Requirement and Challenges
Oxide semiconductors (OSs), introduced by the Hosono group in the early 2000s, have evolved from display backplane materials to promising candidates for advanced memory and logic devices. The exceptionally low leakage current of OSs and compatibility with three-dimensional (3D) architectures have recently sparked renewed interest in their use in semiconductor applications. This review begins by exploring the unique material properties of OSs, which fundamentally originate from their distinct electronic band structure. Subsequently, we focus on atomic layer deposition (ALD), a core technique for growing excellent OS films, covering both basic and advanced processes compatible with 3D scaling. The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced. Furthermore, material design strategies, such as cation selection, crystallinity control, anion doping, and heterostructure engineering, are discussed. We also highlight challenges in memory applications, including contact resistance, hydrogen instability, and lack of p-type materials, and discuss the feasibility of ALD-grown OSs as potential solutions. Lastly, we provide an outlook on the role of ALD-grown OSs in memory technologies. This review bridges material fundamentals and device-level requirements, offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
Laser powder bed fusion of biodegradable Zn-4Cu alloy: Processing, microstructure and properties
Zn's natural degradability and biocompatibility make it a promising candidate for implants, however, its mechanical properties remain insufficient for bone applications. In this study, the performance of Zn was enhanced by developing Zn-Cu alloys via laser powder bed fusion (LPBF). Optimal LPBF parameters for forming stable tracks were achieved by adjusting laser power and scanning speed. Under optimized conditions of 100 W and 100 mm/s, high-density (99.58%) Zn-Cu alloys with improved hardness (68.2HV) and yield strength (160 MPa) were achieved. These improvements are attributed to solid solution strengthening, segregation strengthening, and grain refinement. The Zn-Cu alloys also demonstrated favorable degradation behavior, with a rate of 0.16 mm/year. This degradation is primarily driven by micro-galvanic corrosion between the CuZn5 phase and Zn matrix, along with refined grains and increased grain boundary density. This work demonstrates a viable strategy for fabricating Zn-based implants with enhanced structural integrity and mechanical performance via LPBF.