Periodic Reporting for period 1 - ORGUP (ORGanic UPconversion device for SWIR imaging)
Période du rapport: 2023-12-01 au 2025-05-31
Short-wave infrared (SWIR) imaging is a powerful tool to access and visualize the composition of materials and biological tissues contact free and in real time. Extending the sensitivity of the human eye (400- 700nm), SWIR radiation (900-1700nm) outperforms visible light detection, as material specific, strong absorption peaks allow to differentiate a multitude of chemical compositions and its penetration through many surfaces exposes the underlying structures. Beyond inspection and quality assurance in industrial manufacturing processes – including agriculture, pharmaceutics, chemicals, photovoltaics, wafers, metals and glasses – SWIR imaging is also applied in industrial waste sorting, environmental vision and medical diagnostics. In-vivo deep-tissue bioimaging, exploiting the second biological window (1000 - 1350 nm) is used in cancer research and offers a resolution of a few millimetres. So far, commercial SWIR imaging relies on cameras based on inorganic semiconductors, i.e. germanium (Ge) or indium gallium arsenide (InGaAs). The complex manufacturing resulting in camera prices in the range of 25k€ hinders that consumers or low-end applications (e.g. smartphones) can make use of the vast application potential of SWIR imaging.
This project takes steps to enable remote, real-time & high-resolution SWIR imaging - at low cost, without toxic elements. We develop all-organic, ultra-thin up-conversion devices combined with silicon cameras as an attractive alternative for SWIR imaging. The organic upconversion devices convert invisible SWIR images into visible images, being then captured by conventional low-cost cameras, visible-image sensors, or the naked eye.
ORGUP aims to extend the sensitivity limit of organic SWIR upconverters and demonstrate for the first-time affordable SWIR upconversion up to 1400 nm. Additionally, the construction of upconversion devices from allorganic materials, e.g. free of toxic heavy-metals, will further emphasize the attractiveness of the technology, opening new windows of opportunity for bio-imaging and bio-medical applications. The device will match the need for reliable, high-quality imaging at a low operating voltage (V < 10V), at room temperature or above, with no need for cooling, as well as high resolution thanks to the intrinsic low lateral conduction of organic semiconductors. The imager also will have a low weight and an overall thickness of around 100 nm which gives it the potential to be flexible and conform to curved surfaces.
This project takes steps to enable remote, real-time & high-resolution SWIR imaging - at low cost, without toxic elements. We develop all-organic, ultra-thin up-conversion devices combined with silicon cameras as an attractive alternative for SWIR imaging. The organic upconversion devices convert invisible SWIR images into visible images, being then captured by conventional low-cost cameras, visible-image sensors, or the naked eye.
ORGUP aims to extend the sensitivity limit of organic SWIR upconverters and demonstrate for the first-time affordable SWIR upconversion up to 1400 nm. Additionally, the construction of upconversion devices from allorganic materials, e.g. free of toxic heavy-metals, will further emphasize the attractiveness of the technology, opening new windows of opportunity for bio-imaging and bio-medical applications. The device will match the need for reliable, high-quality imaging at a low operating voltage (V < 10V), at room temperature or above, with no need for cooling, as well as high resolution thanks to the intrinsic low lateral conduction of organic semiconductors. The imager also will have a low weight and an overall thickness of around 100 nm which gives it the potential to be flexible and conform to curved surfaces.
The project has resulted in a few demonstrator videos and 2 manuscripts in preparation. The extension of the wavelength range using this fully organic approach and its incorporation into a demonstrator, as well as the realization of a self-driven device are beyond the state of the art.
- A voltage driven upconvertor (driving voltage = 5V) with cutoff wavelength (1400 nm) beyond was Si realized. Further research in characterizing and improving the stability of the devices is required. The project has generated and excludes some ideas for further improvement of the photon upconversion yield, in which potential IP lies. But further research is needed to explore these pathways.
- Work done in the project on building the demonstrator has resulted in the realization that the need for an external driving voltage inevitably increases the (unwanted) light output under full dark conditions. A self-driven organic up-convertor was therefore developed and has been demonstrated. Patent protection of device concept was investigated but abandoned, as it was found that a similar concept has been proposed for inorganic technologies. Further research is needed to shift wavelength response to wavelengths longer than Si for self-driven device concept. Future IPR possibilities lie in new materials and readout protocols of this device.
- A voltage driven upconvertor (driving voltage = 5V) with cutoff wavelength (1400 nm) beyond was Si realized. Further research in characterizing and improving the stability of the devices is required. The project has generated and excludes some ideas for further improvement of the photon upconversion yield, in which potential IP lies. But further research is needed to explore these pathways.
- Work done in the project on building the demonstrator has resulted in the realization that the need for an external driving voltage inevitably increases the (unwanted) light output under full dark conditions. A self-driven organic up-convertor was therefore developed and has been demonstrated. Patent protection of device concept was investigated but abandoned, as it was found that a similar concept has been proposed for inorganic technologies. Further research is needed to shift wavelength response to wavelengths longer than Si for self-driven device concept. Future IPR possibilities lie in new materials and readout protocols of this device.
- Validation of lab-scale upconversion devices: (i) A novel large batch of SWIR absorbing polymer was synthesized, with an optical gap of 1400 nm and was incorporated into the device stack, using a green, low driving voltage OLEDs. Up-conversion is observed at a driving voltage of 5V, and is on the order of 5%, mainly limited by the photovoltaic quantum efficiency of the novel low gap polymer. (ii) By stacking several devices, we demonstrated biasless upconversion in lab-scale devices. We demonstrate a low cost, low temperature fabrication procedure without the need for lithography for pixelation, still achieving an image resolution of less than 15 um.
- Incorporation of the up-conversion devices into an imaging system as technology demonstrator: we have developed a low cost lens system to project the SWIR upconverted image onto a raspberry pi camera and have developed the readout/imaging software. We have demonstrated imaging of several biological samples using light from a halogen lamp.
- Incorporation of the up-conversion devices into an imaging system as technology demonstrator: we have developed a low cost lens system to project the SWIR upconverted image onto a raspberry pi camera and have developed the readout/imaging software. We have demonstrated imaging of several biological samples using light from a halogen lamp.