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Sensing from the ultraviolet (UV)-visible to infrared (IR) is critical to environmental monitoring and remote sensing, fibre-optic communication, day and night-time surveillance, and emerging medical imaging modalities. Today, separate sensors or materials are required for different sub-bands within the UV to IR wavelength range. In general, AlGaN, Si, InGaAs and PbS based photodetectors (PDs) are used for the four important sub-bands: 0.25 μm-0.4 μm (UV), 0.45 μm-0.8 μm (visible), 0.9 μm-1.7 μm (near IR), 1.5 μm-2.6 μm (middle IR), respectively. To obtain the desired sensitivity, these detectors must be operated at low temperatures (for example, at 4.2 K). Thus, a “breakthrough” technology would be enabled by a new class of PDs ---- PDs that do not require cooling to obtain high detectivity; PDs which are fabricated by solution-processing to enable low-cost multi-color, high quantum efficiency, high sensitivity and high speed response over this broad spectral range. The availability of such PDs for use at room temperature (RT) would offer new and important applications. In this presentation, we would like to share with you how we approach RT operated ultrasensitive broad-band solution-processed PDs.
- By developing novel low bandgap semiconducting polymers, we are able to develop RT operated solution-processed polymers PDs with spectral response from 350 nm to 1450 nm, the detectivity over 1013 Jones and linear dynamic range over 100 dB; spectral response from 350 nm to 2500 nm, the detectivity over 1012 Jones;
- By using low bandgap semiconducting polymers mixed with high electrical conductivity PbS quantum dots (QDs), inverted polymer hybrid PDs with spectral response from 300 nm to 25000 nm, the detectivity over 1013 Jones and linear dynamic range over 100 dB are realized;
- By using novel perovskite hybrid materials incorporated with carbon nanotubes, novel n-type newly developed semiconducting polymers, we are able to realize RT operated solution-processed PDs with spectral response from 350 nm to 1400 nm, the detectivity over 1012 Jones and linear dynamic range approximatively 100 dB.
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