- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Highly Conjugated, Fused-Ring, Quadrupolar Organic Chromophores with Large Two-Photon Absorption Cross-Sections in the Near-Infrared
摘要： The two-photon absorption (2PA) properties are investigated for two series of organic, π-conjugated, fused-ring, quadrupolar A-π-D-π-A chromophores of the type originally developed as non-fullerene acceptors for organic photovoltaics. These molecules are found to exhibit large nondegenerate two-photon absorption (ND2PA) cross-sections (ca. 6-27 × 103 GM) in the near infrared (NIR). In the first series, involving molecules of varying core size, ND2PA spectra and cross-sections characterized by femtosecond ND2PA spectroscopy in chloroform solutions reveal that increases in core size, and thus conjugation length, leads to substantially red-shifted and enhanced 2PA. In a second series, variation of the strength of the terminal acceptor (A) with constant core size (7 rings, indacene-based) led to less dramatic variation in the 2PA properties. Among the two core types studied, compounds in which the donor has a thieno[3,2-b]thiophene center demonstrate larger 2PA cross-sections than their indacene-centered counterparts, due to the greater electron-richness of their cores amplifying intramolecular charge transfer. Excited-state absorption (ESA) contributions to nonlinear absorption measured by open-aperture Z-scans are deduced for some of the compounds by analyzing the spectral overlap between 2PA bands and NIR ESA transitions obtained by ND2PA and transient absorption measurements, respectively. ESA cross-sections extracted from transient absorption and irradiance-dependent open-aperture Z-scans are in reasonable agreement and their moderate magnitudes (ca. 10-21 m2) suggest that, although ESA contributions are non-negligible, the effective response is predominantly instantaneous 2PA.
关键词： pump-probe spectroscopy,Nonlinear optics,Z-scan,organic optoelectronics,ultrafast spectroscopy,two-photon absorption
更新于2025-09-23 15:21:01
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Comment on a??Cooperative Behaviors in Amplified Emission from Single Microcrystals of Thiophene/Phenylene Coa??Oligomers toward Organic Polariton Lasera??
摘要： Yanagi et al. recently reviewed their progress in the field of amplified emission of thiophene/phenylene co-oligomers (TPCO) single crystals (Adv. Opt. Mater. 2019, 7, 1900136), which are a promising platform for highly efficient organic light-emitting devices. In this comment, the most intriguing experimental data from this paper are naturally and easily explained as an effect of unintentional impurities or molecular self-dopants that appear in the course of chemical synthesis of TPCO.
关键词： lasers,organic photoluminescence,thiophene/phenylene co-oligomers,molecular self-doping,organic optoelectronics
更新于2025-09-23 15:19:57
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Solutiona??Processable 2D Materials Applied in Lighta??Emitting Diodes and Solar Cells
摘要： The last decades have witnessed a remarkable scientific progress in the field of organic and perovskite optoelectronics. Two-dimensional (2D) materials are an attractive building block for next-generation devices, thanks to their unique physical, optical, and electric characteristics including atomically thin bodies, high transmittance, ultralight weight, and tunable band structures. The state-of-the-art optoelectronic devices utilizing 2D materials mainly rely on 2D thin films grown by chemical vapor deposition. Although good device performances have been demonstrated, a huge gap between fundamental studies and practical applications remains, because of the high cost and troublesome transfer/restacking processes. Therefore, flexible and transparent light-emitting diodes (LEDs) and solar cells (SCs) containing solution-processed 2D materials from top-down exfoliation methods have recently emerged as promising candidates for future light conversion and emission devices. They combine ease of processing, tailorable optoelectronic features, facile integration with complementary layers, compatibility with arbitrary substrates, and enhanced performances. In addition, the latest processing techniques (such as ink-jet printing, spray coating) also offer the opportunity for the scaled-up fabrication of square-meter-scale low-cost device systems. Recent advances, challenges, and future perspectives of solution-processed 2D materials for usage in emerging LEDs and SCs applications are discussed here.
关键词： perovskite optoelectronics,solution process,organic optoelectronics,2D materials
更新于2025-09-19 17:13:59
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Organic Multi-Channel Optoelectronic Sensors for Wearable Health Monitoring
摘要： Recent progress in printed optoelectronics and their integration in wearable sensors have created new avenues for research in reflectance photoplethysmography (PPG) and oximetry. The reflection-mode sensor, which consists of light emitters and detectors, is a vital component of reflectance oximeters. Here, we report a systematic study of the reflectance oximeter sensor design in terms of component geometry, light emitter and detector spacing, and the use of an optical barrier between the emitter and the detector to maximize sensor performance. Printed red and near-infrared (NIR) organic light-emitting diodes (OLEDs) and organic photodiodes (OPDs) are used to design three sensor geometries: (1) Rectangular geometry, where square OLEDs are placed at each side of the OPD; (2) Bracket geometry, where the OLEDs are shaped as brackets and placed around the square OPD; (3) Circular geometry, where the OLEDs are shaped as block arcs and placed around the circular OPD. Utilizing the bracket geometry, we observe 39.7% and 18.2% improvement in PPG signal magnitude in the red and NIR channels compared to the rectangular geometry, respectively. Using the circular geometry, we observe 48.6% and 9.2% improvements in the red and NIR channels compared to the rectangular geometry. Furthermore, a wearable two-channel PPG sensor is utilized to add redundancy to the measurement. Finally, inverse-variance weighting and template matching algorithms are implemented to improve the detection of heart rate from the multi-channel PPG signals.
关键词： flexible electronics,printed electronics,pulse oximetry,organic optoelectronics,Reflection photoplethysmography sensor,wearable sensors
更新于2025-09-11 14:15:04