Quantifying radiation from thermal imaging of residential landscape elements

Loveday, Jane; Loveday, Grant; Byrne, Josh; Ong, Boon-lay; Newman, Peter

doi:10.1051/rees/2017041

Cited by 4 publications

(4 citation statements)

References 6 publications

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“…Recent advances in colloidal nanocrystal (NC) photodetectors have begun to challenge commercial mid- (MIR) and longwave infrared (LWIR) detectors on performance. Currently, commercial demand for cheap detectors is almost entirely met by microbolometers, which detect LWIR photons and meet the demand from a market that is estimated to be worth $1.6 B by 2022. , This growth is expected to come from an increased demand from industries such as autonomous vehicles, firefighting, security screening, environmental monitoring, and a larger general civil uptake. − The expected unit cost for a sensor to be competitive is expected to be less than $10. , Mid-infrared (MIR) detectors fabricated using epitaxial growth techniques can outperform microbolometers in imaging metrics, but are very expensive and are unlikely to compete with them on price. ,− As such, there is a real demand for low cost, MIR detectors that can operate at room temperature with superior performance to microbolometers.…”

mentioning

confidence: 99%

300 nm Spectral Resolution in the Mid-Infrared with Robust, High Responsivity Flexible Colloidal Quantum Dot Devices at Room Temperature

Cryer

Halpert

2018

ACS Photonics

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HgTe colloidal nanocrystals (NCs) are used as the sensitizing layer with a scalable, all air-processed patterning method to produce flexible room temperature multicolor detectors operating in the mid-infrared (MIR) spectral region. These devices demonstrate a “color” sensitivity down to 300 nm in the MIR (∼10% of scale), with superior responsivities for this class of device, up to 0.9 A/W, and competitive specific detectivity up to 8 × 109 Jones at 200 Hz and 300 K. Furthermore, these devices utilize a cheap and robust substrate material that allows operation after deformation up to 45° without degradation over many cycles. As such, this offers a template for ultra low-cost MIR detectors with a performance that rivals microbolometers, but with better measurement speed and spectral sensitivity. As such, these devices showcase the advantages of using colloidal NCs in MIR applications.

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mentioning

confidence: 99%

300 nm Spectral Resolution in the Mid-Infrared with Robust, High Responsivity Flexible Colloidal Quantum Dot Devices at Room Temperature

Cryer

Halpert

2018

ACS Photonics

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“…The camera's software (R esearch IR max , v.4.40.12.38; FLIR) was used to capture leaf temperature variations continuously, and to set longwave radiation emissivity for regions of interest. Setting the emissivity to 1, a piece of crumpled aluminium was used to measure T reflect , as this provides an estimation of longwave radiation emitted by the surrounding environment, which is reflected from all directions by the aluminium (Loveday et al ., 2017). To test the homogeneity of the reflected temperature signal over the field of view of the camera, a large piece of crumpled aluminium (20 cm × 30 cm) was placed under the lamp and subjected to three light pulses (1024, 912, 784 μmol m −2 s −1 , each lasting 30 s and followed by 3.5 min darkness).…”

Section: Methodsmentioning

confidence: 99%

Rapid spatial assessment of leaf‐absorbed irradiance

Zhang,

Kaiser,

Marcelis

et al. 2023

New Phytologist

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Summary Image‐based high‐throughput phenotyping promises the rapid determination of functional traits in large plant populations. However, interpretation of some traits – such as those related to photosynthesis or transpiration rates – is only meaningful if the irradiance absorbed by the measured leaves is known, which can differ greatly between different parts of the same plant and within canopies. No feasible method currently exists to rapidly measure absorbed irradiance in three‐dimensional plants and canopies. We developed a method and protocols to derive absorbed irradiance at any visible part of a canopy with a thermal camera, by fitting a leaf energy balance model to transient changes in leaf temperature. Leaves were exposed to short light pulses (30 s) that were not long enough to trigger stomatal opening but strong enough to induce transient changes in leaf temperature that was proportional to the absorbed irradiance. The method was successfully validated against point measurements of absorbed irradiance in plant species with relatively simple architecture (sweet pepper, cucumber, tomato, and lettuce). Once calibrated, the model was used to produce absorbed irradiance maps from thermograms. Our method opens new avenues for the interpretation of plant responses derived from imaging techniques and can be adapted to existing high‐throughput phenotyping platforms.

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“…Currently, commercial demand for cheap detectors is almost entirely met by microbolometers, which thermally detect in the LWIR and meet the demand from a growing market that is estimated to be worth $1.6B by 2022 [1,2]. This growth is expected to come from an increased demand from industries such as autonomous transport, firefighting, security screening, environmental monitoring and a larger general civil uptake [8,11,12,121]. The unit cost for a sensor to be competitive is expected to be less than $10 [1, 2] and although MIR detectors fabricated using epitaxial growth techniques can outperform microbolometers in imaging metrics, they are very expensive and are very unlikely to ever compete with them on price [2,[122][123][124].…”

Section: Motivationmentioning

confidence: 99%

Device Applications of Solution Processed MIR Semiconductor Nanocrystal Thin Films

Cryer¹

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<p>Colloidal semiconductor nanocrystals (NCs) with bandgaps less than 1 eV allow the development of mid wave infrared (MIR) sensitive detectors that exploit the benefits of colloidal materials, primarily bandgap selection and solution deposition. Additionally, the electrical behaviour of these films can be examined for characteristics that can increase the functionality of NC based detectors. The production of devices that are designed to be competitive as ultra-low-cost, room temperature MIR detectors, operating with photonic, rather than thermal detection is detailed. The evolution of the colloidal synthesis, spray deposition methods, substrate materials and post deposition treatments used here lead to highly robust and high performing devices. These devices demonstrate a “colour” sensitivity down to 300 nm in the MIR (≈10 % of scale), with superior responsivities for this class of device, up to 0.9 AW⁻¹, and competitive specific detectivity up to 8 × 10⁹ Jones at 200 Hz and 300 K. Furthermore, these devices utilise a cheap and robust substrate material that allows operation after deformation up to 45 ° without degradation over many cycles. These devices offer a template for ultra-low-cost MIR detectors with performance that rivals microbolometers but with better measurement speed and spectral sensitivity. As such these devices showcase the key advantages of using colloidal NCs in MIR applications. Planar and fully air processed thin film devices that demonstrate photo-induced memristive behaviour and can be used as a transistors, photode-tectors or memory devices are investigated. Following long term (60 h) air exposure, unpackaged NC films develop reliable memristive characteristics in tandem with temperature, gate and photoresponse. On/off ratios of more than 50 are achieved and the devices show long term stability, producing repeatable metrics over days of measurement. The on/off behaviour is shown to be dependent on previous charge flow and carrier density, implying memristive rather than switching behaviour. These observations are described within a long term trap filling model. This work represents an advance in the integration of NC films into electronic devices, which may lead to the development of multi-functional electronic components. Building on the previous work the steps taken to move from a planar device, that works well in controlled conditions, to a multi-pixel sensor that can demonstrate MIR video imaging at room temperature in a noisy environment are shown. This is achieved with a 15 pixel detector that consists only of a polymer substrate and solution patterned NC pixels. This device can detect a 373 K object with the device at 298 K in a noisy environment. This performance is enabled by photogain at 5 V bias that reaches a maximum External Quantum Efficiency (EQE) of 1940 ± 290 % for a pixel with a 3.3 µm bandgap. Through the use of four separate bandgaps it is shown that “multicolour” thermal imaging systems can deliver another layer of information, on top of intensity, to the user. The behaviour of the system is examined under use and it is shown that the photoconductive device behaves as expected with regards to bias, and that trap enabled gain is sensitive to total incident flux, more than the spectral energy distribution of the target. Finally, it is shown that solution patterned QD fabrication methods can deliver electrical reproducibility between pixels that is sufficient to allow an imaging plane of multiple pixels. The somewhat neglected tin chalcogenide semiconductor nanocrystals are investigated and inverse MIR detection at room temperature is demonstrated with planar, solution and airprocessed PbSnTe and SnTe QD devices. The detection mechanism is shown to be mediated by an interaction between MIR radiation and the vibrational stretches of adsorbed hydroxyl species at the oxdised NC surface. Devices are shown to possess mAW⁻¹ responsivity via a reduction in film conductance due to MIR radiation and, unlike classic MIR photoconductors, are unaffected by visible wavelengths. As such these devices offer the possibility of MIR thermal imaging that has an intrinsic solution to the blinding caused by higher energy light sources. In summary, it is shown that semiconductor NCs with an all ambient fully solution processed deposition and ligand exchange procedure can be used to create simple, robust and cheap devices that are beginning to demonstrate metrics on par with current commercial thermal detector systems. It is also shown that these devices can under certain circumstances demonstrate novel behaviours that offer the prospects of enhanced or novel functionality.</p>

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Quantifying radiation from thermal imaging of residential landscape elements

Cited by 4 publications

References 6 publications

300 nm Spectral Resolution in the Mid-Infrared with Robust, High Responsivity Flexible Colloidal Quantum Dot Devices at Room Temperature

300 nm Spectral Resolution in the Mid-Infrared with Robust, High Responsivity Flexible Colloidal Quantum Dot Devices at Room Temperature

Rapid spatial assessment of leaf‐absorbed irradiance

Device Applications of Solution Processed MIR Semiconductor Nanocrystal Thin Films

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