High‐Performance Wearable Organic Photodetectors by Molecular Design and Green Solvent Processing for Pulse Oximetry and Photoplethysmography

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(9)

Published: Dec. 6, 2023

Abstract White‐light detection from the visible to near‐infrared region is central many applications such as high‐speed cameras, autonomous vehicles, and wearable electronics. While organic photodetectors (OPDs) are being developed for applications, several challenges must be overcome produce scalable high‐detectivity OPDs. This includes issues associated with low responsivity, narrow absorption range, environmentally friendly device fabrication. Here, an OPD system processed 2‐methyltetrahydrofuran (2‐MeTHF) sets a record in light detectivity, which also comparable commercially available silicon‐based photodiodes reported. The newly designed employed devices monitor heart rate blood oxygen saturation using flexible OPD‐based finger pulse oximeter. In achieving this, framework detailed understanding of structure–processing–property relationship these OPDs developed. bulk heterojunction (BHJ) thin films 2‐MeTHF characterized at different length scales advanced techniques. BHJ morphology exhibits optimal intermixing phase separation donor acceptor moieties, facilitates charge generation collection process. Benefitting high carrier mobilities shunt leakage current, specific detectivity above 10 12 Jones over 400–900 nm, higher than those reference chlorobenzene ortho ‐xylene.

Language: Английский

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Near-Infrared Electron Acceptors with Cyano-Substituted 2-(3-Oxo-2,3-dihydroinden-1-ylidene)malononitrile End-Groups for Organic Solar Cells

ACS Energy Letters, Journal Year: 2023, Volume and Issue: 8(6), P. 2641 - 2651

Published: May 17, 2023

Near-infrared (NIR) electron acceptors are critical components for constructing organic solar cells (OSCs). Herein, we report a set of A-DA′D-A-type with end-groups cyano-substituted 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (CN-IC), which possesses the strongest electron-withdrawing ability among reported to date. An optical bandgap as low 1.29 eV was obtained CN-IC end-groups, is decreased by 0.12 respect that reference acceptor. Meanwhile, deep-lying frontier molecular orbital energy levels were maintained in these acceptors. These advantages endow broad light-harvesting range and capacity match prevalent polymer donors. Consequently, OSCs power conversion efficiency 18.1% obtained. results suggest huge potential NIR

Language: Английский

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8-nm narrowband photodetection in diamonds

Opto-Electronic Science, Journal Year: 2023, Volume and Issue: 2(7), P. 230010 - 230010

Published: Jan. 1, 2023

Spectrally-selective photodetection plays a crucial role in various applications, including target imaging and environmental monitoring. Traditional deep-ultraviolet (DUV) narrowband systems consist of broadband photodetectors filters, which complicates the architecture constrains quality. Here, we introduce an electronic-grade diamond single-crystal photodetector exhibiting exceptionally narrow spectral response DUV range with full width at half maximum 8 nm. By examining varying dislocation densities, propose that mitigating defect-induced trapping effect to achieve charge collection narrowing, assisted by free exciton radiative recombination, is effective strategy for photodetection. The superior performance this device evidenced through light sources, showcasing its capability differentiate between distinct sources monitor human-safe sterilization systems. Our findings underscore promising potential applications offer valuable technique identifying diamond.

Language: Английский

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Highly Sensitive Resonance-Enhanced Organic Photodetectors for Shortwave Infrared Sensing

ACS Energy Letters, Journal Year: 2024, Volume and Issue: 9(4), P. 1446 - 1454

Published: March 11, 2024

Shortwave infrared (SWIR) sensing has various applications, including night vision, remote sensing, and medical imaging. SWIR organic photodetectors (OPDs) offer advantages such as flexibility, cost-effectiveness, tunable properties; however, lower sensitivity limited spectral coverage compared to inorganic counterparts are major drawbacks. Here, we propose a simple yet effective widely applicable strategy extend the wavelength detection range of OPD longer wavelength, using resonant optical microcavity. We demonstrate proof-of-concept in PTB7-Th:COTIC-4F blend system, achieving external quantum efficiency (EQE) > 50% over broad spectrum (450–1100 nm) with peak specific detectivity (D*) 1.1 × 1013 Jones at λ = 1100 nm, while speed linearity preserved. By employing small-molecule-acceptor IR6, EQE 35% D* 4.1 1012 obtained 1150 nm. This research emphasizes importance design optoelectronic devices, proposing simpler method broaden photodetection traditional approaches narrow gap absorbers.

Language: Английский

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Ultranarrow-bandgap small-molecule acceptor enables sensitive SWIR detection and dynamic upconversion imaging

Science Advances, Journal Year: 2024, Volume and Issue: 10(23)

Published: June 5, 2024

Short-wavelength infrared (SWIR) light detection plays a key role in modern technologies. Emerging solution-processed organic semiconductors are promising for cost-effective, flexible, and large-area SWIR photodiodes (OPDs). However, the spectral responsivity ( R ) specific detectivity D *) of OPDs restricted by insufficient exciton dissociation high noise current. In this work, we synthesized an small molecule with coverage 0.3 to 1.3 micrometers peaking at 1100 nanometers. The photodiode, optimized dissociation, charge injection, transmittance, achieves record 0.53 ampere per watt * 1.71 × 10 13 Jones 1110 nanometers under zero bias. 1 1.2 surpasses that uncooled commercial InGaAs photodiode. Furthermore, semitransparent all-organic upconversion devices integrating photodiode realized static dynamic SWIR-to-visible imaging, along excellent efficiency spatial resolution. This work provides alternative insights developing sensitive detection.

Language: Английский

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