Short‐Wave Infrared Sensor by the Photothermal Effect of Colloidal Gold Nanorods

Abstract

Photodetection in the short-wave infrared (SWIR) spectrum is a challenging task achieved often by costly low bandgap compound semiconductors involving highly toxic elements. In this work, an alternative low-cost approach is reported for SWIR sensors that rely on the plasmonic-induced photothermal effect of solution-processed colloidal gold nanorods (Au NRs). A series of uniform solution-processed Au NRs of various aspect ratios are prepared exhibiting a strong and well-defined longitudinal localized surface plasmon resonance (L-LSPR) maximum from 900 nm to 1.3 µm. A hybrid device structure is fabricated by applying Au NRs on the surface of a thermistor. Under a monochromatic illumination, hybrid Au-NR/thermistor devices exhibit a clear photoresponse in the form of photoinduced resistance drop in the wavelength window from 1.0 to 1.8 µm. The photoresponsivity of such hybrid devices reaches a maximum value of 4.44 × 10 Ω W at λ = 1.4 µm (intensity = 0.28 mW cm ), a wavelength in agreement with the L-LSPR of the Au NRs applied. Colloidal Au NRs, capable to perform fast conversion between photon absorption and thermal energy, thus open an interesting avenue for alternative low-cost SWIR photodetection.

Plasmon Coupled Colloidal Gold Nanorods for Near‐Infrared and Short‐Wave‐Infrared Broadband Photodetection

“…To compare with other colloidal nanoparticle based photodetectors, Table 1 summarizes the major characteristics of colloidal plasmonic metallic nanoparticles for visible, near‐IR, and/or SWIR photodetectors from previous applications and the current work. Despite the fact that colloidal plasmonic metallic nanoparticles, e.g., NPs [ 40–43 ] and NRs, [ 23,36,44 ] have been successfully applied previously for photodetection, in comparison to previous studies, the current results demonstrate a remarkable broadband detection covering the NIR‐SWIR spectrum from λ = 800 to 2000 nm, with a detection speed comparable or faster than many previous reports. Innovations on solution‐processed broadband photodetection devices in the NIR‐SWIR spectrum is particularly important because current technologies detecting this spectrum window suffer from high cost and often demand highly toxic heavy metal elements.…”

“…[35] On photodetection, Au NRs have been proved to be a promising medium due to their remarkable fast plasmonic-induced photothermal effect. [36,37] On this aspect, SWIR photodetectors based on a single type of Au-NRs have been demonstrated by depositing Au NRs on a 2 by 10 µm platinum short microwire. [38] To our best knowledge, broadband photodetection achieved by plasmon coupled colloidal Au NRs of different dimensions has not been demonstrated.…”

Enhanced Photocarrier Generation with Selectable Wavelengths by M‐Decorated‐CuInS2 Nanocrystals (M = Au and Pt) Synthesized in a Single Surfactant Process on MoS2 Bilayers

“…Previous works have revealed the enhanced electromagnetic field and the light confinement effect by combining plasmonic metal nanostructures and 2D‐based photodetectors, leading to the improvement of the light absorption under the visible spectral region . Also, by applying metal particles with diverse morphologies such as nanoparticles, nanotubes/nanowires, nanodiscs, core–shell particles and creating nanoarray patterns, the resonance wavelength can be tunable. To achieve the better performance of photodetector on the MoS 2 layered material, we aim to combine highly absorptive CuInS 2 (CIS) nanoparticles with noble metal nanoparticles as the photosensitizer to enhance the intrinsic absorptivity of noble metal nanocrystals.…”

Long-Term Stable Near-Infrared–Short-Wave-Infrared Photodetector Driven by the Photothermal Effect of Polypyrrole Nanostructures

“…Colloidal Au-NRs used in this work were synthesized by following previously described methods 9,53 . Au nanoparticle seed solution: After mixing 5 ml of 0.5 mM HAuCl 4 solution with 5 ml of 0.2 M CTAB solution, 1 ml of 0.006 M NaBH 4 solution was added followed by vigorously stirring for 2 minutes.…”