RESUMO
Organic photodetectors, as an emerging wearable photoplethysmographic (PPG) technology, offer exciting opportunities for next-generation photonic healthcare electronics. However, the mutual restraints among photoresponse, structure complexity, and fabrication cost have intrinsically limited the development of organic photodetectors for ubiquitous health monitoring in daily activities. Here, an effective route to dramatically boost the performance of organic photodetectors with a solution-processed integration circuit for health monitoring application is reported. Through creating an ideal metal-semiconductor junction interface that minimizes the trap states within the device, solution-printed organic field-effect transistors (OFETs) are achieved with an ultrahigh signal amplification efficiency of 37.1 S A-1 , approaching the theoretical thermionic limit. Consequently, monolithic integration of the OFET with an organic photoconductor enables the remarkable amplification of photoresponse signal-to-noise ratio by more than four orders of magnitude from 5.5 to 4.6 × 105 , which is able to meet the demand for accurately extracting physiological information from the PPG waveforms. This work offers an effective and versatile approach to greatly enhance the photodetector performance, promising to revolutionize health monitoring technologies.
RESUMO
Narrow-bandgap Sn-Pb mixed perovskite single crystals are highly promising as photoactive materials for efficient and low-cost near-infrared (NIR) photodetectors. However, because of the significant difference in the crystallization velocities for Pb- and Sn-based perovskites, Sn-Pb mixed perovskites are peculiarly prone to phase separation during the crystallization process, causing the degradation of the optical and electronic properties of materials. Herein, we propose a low-temperature space-confined technique (LT-SCT) that simultaneously reduces the crystallization velocities of pure Sn and Pb perovskites, enabling the fabrication of pure-phase (FASnI3)0.1(MAPbI3)0.9 single crystals. The resulting (FASnI3)0.1(MAPbI3)0.9 single crystals exhibit excellent crystallinity with a high hole mobility of 7.44 × 103 cm2 V-1 s-1 and a low surface trap density of 1.88 × 109 cm-2. These properties benefit the application of (FASnI3)0.1(MAPbI3)0.9 single crystals in self-powered NIR photodetectors and yield outstanding comprehensive performance, especially with a broad linear dynamic range of up to 163.5 dB, a large responsivity (R) of 0.53 A W-1, and a fast response speed of 22.78 µs in the NIR spectral region (750-860 nm). Furthermore, high-quality NIR imaging and wearable health monitoring are achieved by employing high-performance and self-driven NIR photodetectors. This work contributes to developing Sn-Pb mixed perovskite single crystals and provides a promising candidate for efficient and low-cost NIR photodetection.
RESUMO
To investigate the effects of gravel content on runoff and sediment yield on Lou soil accumulation slopes, we conducted indoor simulation rainfall experiments and examined the characteristics of runoff and sediment yield on accumulation slopes with five gravel contents (10%, 20%, 30%, 40%, 50%) under four rainfall intensities (1.0, 1.5, 2.0, 2.5 mm·min-1), with a no gravels slope as control. The average runoff rate under different test conditions ranged from 2.18 to 13.07 L·min-1. The average runoff rate was the maximum under the gravel content of 10% (or 20%) and the minimum under the 50% gravel content. The average flow velocity ranged from 0.06 to 0.22 m·s-1. The variation of flow velocity was complex. The smaller the gravel content, the larger the range of variation and the coefficient of variation. The average flow velocity reached the maximum when the gravel content was 10%. The presence of gravel effectively inhibited the sediment yield, and the sediment reduction benefit reached 84.2%. The rainfall intensity had more influence on the average sediment yield rate than gravel content. Results of partial correlation analysis showed that gravel content was significantly negatively correlated with the ave-rage runoff rate, the average flow velocity, and the average sediment yield rate. The relationships between the ave-rage sediment yield and the average runoff rate, the average flow velocity, and their interaction were all extremely significant linear functions, with the strongest relationship between the average sediment yield and the average runoff rate. This study could provide references for the control of soil erosion and the establishment of erosion models for engineering accumulations in Lou soil areas.
Assuntos
Solo , Movimentos da Água , Chuva , Receptor para Produtos Finais de Glicação Avançada , Sedimentos GeológicosRESUMO
Highly ordered organic semiconductor single-crystal (OSSC) arrays are ideal building blocks for functional organic devices. However, most of the current methods are only applicable to fabricate OSSC arrays of a single component, which significantly hinders the application of OSSC arrays in integrated organic circuits. Here, we present a universal approach, termed three-dimensional (3D) wettability-induced sequential assembly that can programmatically and progressively manipulate the crystallization locations of different organic semiconductors at the same spatial position using a 3D microchannel template, for the fabrication of the two-component OSSC arrays. As an example, we successfully prepared two-component, bilayer structured OSSC arrays consisting of n-type N,N'-bis(2-phenylethyl)-perylene-3,4:9,10-tetracarboxylic diimide and p-type 6,13-bis(triisopropylsilylethynyl)pentacene microbelts. The bicomponent OSSCs show ambipolar carrier transport properties with hole and electron mobilities of 0.342 and 0.526 cm2 V-1 s-1, respectively. Construction of complementary inverters is further demonstrated based on the two-component OSSCs. The capability of integration of multicomponent OSSC arrays opens up unique opportunities for future high-performance organic complementary circuits.