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Abstract The development of infrared (IR) plastic optics for infrared thermal imaging, particularly, in the long‐wave IR (LWIR) spectrum (7–14 µm) is an area of growing technological interest due to the potential advantages associated with plastic optics (e.g., moldability and low cost). The development of a new class of optical polymers, chalcogenide‐based inorganic/organic hybrid polymers (CHIPs) derived from the inverse vulcanization of elemental sulfur, has enabled significant improvements in IR transparency due to reduction of IR absorbing organic comonomer units. The vast majority of effort has focused on new chalcogenide hybrid polymer synthesis and optical property improvements (e.g., refractive index, Abbe number, and LWIR transmission); however, fabrication and IR imaging methodology to prepare optical components has not been demonstrated, which remains critical to develop viable IR plastic optics. A new methodology is reported to fabricate optical components and evaluate LWIR imaging performance of this emerging class of optical polymers. New diffractive flat optics with a Fresnel lens design for these materials have been developed, along with a basic LWIR imaging system to evaluate CHIPs for LWIR imaging. This system‐based approach enables correspondence of copolymer structure‐property correlations with LWIR imaging performance, along with demonstration of room temperature LWIR imaging.
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Radiation Hardened Infrared Photodetectors Based on a Narrow Bandgap Conjugated Polymer Semiconductor
Abstract Space missions critically rely on sensors that operate throughout the near‐ to longwave infrared (NIR – LWIR, λ = 0.9–14 µm) regions of the electromagnetic spectrum. These sensors capture data beyond the capabilities of traditional optical tools and sensors, critical for the detection of thermal emissions, conducting atmospheric studies, and surveillance. However, conventional NIR‐LWIR detectors depend on bulky, cryogenically cooled semiconductors, making them impractical for broader space‐based applications due to their high cost, size, weight, and power (C‐SWaP) demands. Here, an IR photodetector using a solution‐processed narrow bandgap conjugated polymer is demonstrated. This direct bandgap photoconductor demonstrates exceptional infrared sensitivity without cooling and has minimal changes in figures‐of‐merit after substantial ionizing radiation exposure up to 1,000 krad – equivalent to three years in the most intense low Earth orbit (LEO). Its performance and resilience to radiation notably surpass conventional inorganic detectors, with a 7.7 and 98‐fold increase in radiation hardness when compared to epitaxial mercury cadmium telluride (HgCdTe) and indium gallium arsenide (InGaAs) photodiodes, respectively, offering a more affordable, compact, and energy‐efficient alternative. This class of organic semiconductors provides a new frontier for C‐SWaP optimized IR space sensing technologies, enabling the development of new spacecraft and missions with enhanced observational capabilities.
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- Award ID(s):
- 2323665
- PAR ID:
- 10587322
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Volume:
- 11
- Issue:
- 11
- ISSN:
- 2199-160X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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