Flexible broad-spectrum image sensor based on quantum dot/nanowire composite nanostructure
Broad-spectrum imaging technology can usually detect and image the environment or objects in multiple bands (such as ultraviolet, visible, near-infrared, mid-infrared, far-infrared, etc.). In a complex environment, due to the ability to obtain information in multiple bands, wide-spectrum imaging technology has a huge advantage over single-band imaging technology in target detection and recognition. Therefore, this technology has a wide range of applications in biomedicine, criminal investigation, mineral exploration, optical communication and all-weather monitoring. However, traditional wide-spectrum image sensors are usually based on rigid substrates such as silicon, which have disadvantages such as difficult to bend, poor impact resistance, and not easy to carry, and cannot meet the diverse application scenarios and needs of the current society within a certain range. With the increasing demand for flexible electronic equipment, a variety of flexible sensor devices have been developed one after another, such as flexible temperature sensors, pressure sensors, and gas sensors. Therefore, the development of flexible wide-spectrum image sensors is important to meet people's diverse applications. Demand is of great significance. Recently, Shen Guozhen’s research group at the State Key Laboratory of Superlattices of the Institute of Semiconductors of the Chinese Academy of Sciences used a two-step vapor deposition method to modify the surface of wide-band gap n-type Zn2SnO4 (~3.6 eV) nanowires with narrow band gap p-type SnS (~1.3 eV ) Quantum dots, and a flexible PET plastic film as the substrate, successfully developed a flexible UV-Vis-NIR wide-spectrum image sensor. The study found that compared with pure Zn2SnO4 nanowire devices, SnS quantum dot-modified Zn2SnO4 nanowire devices have a higher UV response and a broadened near-infrared spectral response range. This is mainly due to the combination of Zn2SnO4 nanowires and SnS quantum dots. The quasi-type II heterojunction and the narrow band gap of SnS quantum dots formed between them. Because the device is made on a flexible PET film substrate, and Zn2SnO4 nanowires have good toughness due to their ultra-high aspect ratio and a radius of curvature as small as micrometers, the device has excellent bendability. And mechanical stability, even after 5000 bending cycles, there is no significant performance degradation. Under bending conditions, the prepared flexible broad-spectrum image sensor can clearly identify the target pattern composed of red and white light, indicating its potential for future flexible broad-spectrum imaging applications. This work provides a new design idea and feasibility process for obtaining high-performance flexible wide-spectrum image sensors.
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