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1.
Adv Mater ; : e2402253, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38553842

RESUMO

Emerging neural morphological vision sensors inspired by biological systems that integrate image perception, memory, and information computing are expected to transform the landscape of machine vision and artificial intelligence. However, stable and reconfigurable light-induced synaptic behavior always relies on independent gateport modulation. Despite its potential, the limitations of uncontrollable defects and ionic characteristics have led to simpler, smaller, and more integration-friendly two-terminal devices being used as sidelines. In this work, the synergy between ion migration barriers and readout voltage is proven to be the key to realizing stable, reconfigurable, and precisely controllable postsynaptic current in two-terminal devices. Following the same mechanism, optical and electrical signal synchronous triggering is proposed to serve as a preprocessing method to achieve a recognition accuracy of 96.5%. Impressively, the gradual ion accumulation during the training process induces photocurrent evolution, serving as a reference for the dynamic learning rate and boosting accuracy to 97.8% in just 10 epochs. The PSC modulation potential under short optical pulse of 20 ns is also revealed. This optoelectronic device with perception, memory, and computation capabilities can promote the development of new devices for future photonic neural morphological circuits and artificial vision.

2.
Adv Mater ; : e2400090, 2024 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-38433566

RESUMO

Low-toxicity tin halide perovskites with excellent optoelectronic properties are promising candidates for photodetection. However, tin halide perovskite photodetectors have suffered from high dark current owing to uncontrollable Sn2+ oxidation. Here, 2-cyanoethan-1-aminium iodide (CNI) is introduced in CH(NH2 )2 SnI3 (FASnI3 ) perovskite films to inhibit Sn2+ oxidation by the strong coordination interaction between the cyano group (C≡N) and Sn2+ . Consequently, FASnI3 -CNI films exhibit reduced nonradiative recombination and lower trap density. The self-powered photodetector based on FASnI3 -CNI exhibits low dark current (1.04 × 10-9 A cm-2 ), high detectivity (2.2 × 1013 Jones at 785 nm), fast response speed (2.62 µs), and good stability. Mechanism studies show the increase in the activation energy required for thermal emission and generated carriers, leading to a lower dark current in the FASnI3 -CNI photodetector. In addition, flexible photodetectors based on FASnI3 -CNI, exhibiting high detectivity and fast response speed, are employed in wearable electronics to monitor the human heart rate under weak light and zero bias conditions. Finally, the FASnI3 -CNI perovskite photodetectors are integrated with a 32 × 32 thin-film transistor backplane, capable of ultraweak light (170 nW cm-2 ) real-time imaging with high contrast, and zero power consumption, demonstrating the great potential for image sensor applications.

3.
Nat Commun ; 15(1): 2066, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453948

RESUMO

Free-space coupling, essential for various communication applications, often faces significant signal loss and interference from ambient light. Traditional methods rely on integrating complex optical and electronic systems, leading to bulkier and costlier communication equipment. Here, we show an asymmetric 2D-3D-2D perovskite structure device to achieve a frequency-selective photoresponse in a single device. By combining two electromotive forces of equal magnitude in the opposite directions, the device output is attenuated to zero under constant light illumination. Because these reverse photodiodes have different response speeds, the device only responds near a certain frequency, which can be tuned by manipulating the 2D perovskite components. The target device achieves an ultrafast response of 19.7/18.3 ns in the frequency-selective photoresponse range 0.8-9.7 MHz. This anti-interference photodetector can accurately transmit character and video data under strong light interference with a source intensity of up to 454 mW cm-2.

4.
Adv Mater ; : e2400279, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548708

RESUMO

Light detection and ranging (LiDAR) is indispensable in applications such as unmanned aerial vehicles, autonomous driving, and biomimetic robots. However, the precision and available distance of LiDAR are constrained by the speed and sensitivity of the photodetector, necessitating the use of expensive and energy-consuming avalanche diodes. To address these challenges, in this study, a pyroelectricity-based acceleration strategy with 2D-(graded 3D) perovskite heterojunction is proposed to achieve a record high speed (27.7 ns with an active area of 9 mm2, and 176 ps with an active area of 0.2 mm2) and high responsivity (0.65 A W-1) at zero bias. This success is attributed to the unique mechanism where the electrons from the pyroelectric effect at the Cl-rich 2D/3D interface directly recombine with excess holes during light-dark transitions, breaking speed limitations related to carrier mobility and capacitive effect. Furthermore, the introduced pyroelectric effect significantly enhances the photoresponse, resulting in a self-powered external quantum efficiency exceeding 100%. The study also demonstrates precise position detection at the centimeter level. In conclusion, this research presents a pioneering approach for developing high-speed photodiodes with exceptional sensitivity, mitigating energy and cost concerns in LiDAR applications.

5.
Adv Mater ; 36(2): e2306415, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37660273

RESUMO

The operational stability is a huge obstacle to further commercialization of perovskite solar cells. To address this critical issue, in this work, uracil is introduced as a "binder" into the perovskite film to simultaneously improve the power conversion efficiency (PCE) and operational stability. Uracil can efficiently passivate defects and strengthen grain boundaries to enhance the stability of perovskite films. Moreover, the uracil also strengthens the interface between the perovskite and the Tin oxide (SnO2 ) electron transport layer to increase the binding force. The uracil-modified devices deliver a champion PCE of 24.23% (certificated 23.19%) with negligible hysteresis at active area of 0.0625 cm2 . In particular, the optimal device exhibits over 90% of its initial PCE after tracking for ≈6000 h at its maximum power point under continuous light, indicating its superior operational stability. Moreover, the devices also show great reproducibility in both PCE and operational stability.

6.
Sci Bull (Beijing) ; 69(3): 334-344, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38105158

RESUMO

Perovskite solar cells offer great potential as a sustainable power source for distributed electronic devices that operate indoors. However, the impact of advanced lighting technology, especially the widely used pulse width modulation (PWM) technology, on perovskite photovoltaics has been ignored. Herein, for the first time in photovoltaics, we find that the light impact emitted by the PWM lighting system caused dynamic strain in perovskite thin films, induced phase separation, and accelerated the generation of metallic lead (Pb0) defects, leading to irreversible degradation of the cell performance after 27 h (T80). To address this issue, formamidinium triiodide (FAI3) is chosen to treat the surface of the perovskite and release residual stress, resulting in reduced lattice deformation during dynamic strain processes. Meanwhile, it suppresses harmful Pb0 defects and reduces Voc loss at low light intensity. The champion device achieves impressive power conversion efficiency (PCE) of 35.14% and retains 99.5% of the initial PCE after continuous strobe light soaking for 2160 h.

7.
Am J Transl Res ; 15(11): 6605-6612, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38074802

RESUMO

OBJECTIVE: This study aimed to assess the clinical efficacy of combining vacuum sealing drainage with full irrigation in managing oral and maxillofacial space infections and its impact on serum inflammatory factor levels in patients. METHODS: We retrospectively analyzed data from 110 patients with oral and maxillofacial space infections treated at our hospital between February 2018 and March 2022. Among them, 50 patients underwent simple negative pressure closed drainage (control group), while 60 patients received combined full irrigation using 0.9% sodium chloride solution (observation group). We compared clinical treatment outcomes, treatment duration, antibiotic usage duration, quality of life scores, Visual Analogue Scale (VAS) scores, changes in serum IL-6 and TNF-α levels before and after treatment, and the incidence of complications between the two groups. Additionally, we conducted an analysis of risk factors influencing patient prognosis. RESULTS: The observation group exhibited significantly superior treatment efficacy compared to the control group (P < 0.05). Treatment and antibiotic usage durations were shorter in the observation group (P < 0.05). VAS scores after treatment were significantly lower in the observation group (P < 0.05). Serum inflammatory factors improved significantly in both groups after treatment, with a more substantial improvement observed in the observation group (P < 0.05). Post-treatment quality of life was significantly higher, and the incidence of complications was lower in the observation group (P < 0.05). The choice of treatment method independently influenced patient prognosis (P < 0.05). CONCLUSION: Combining vacuum sealing drainage with full irrigation is an effective approach for managing oral and maxillofacial space infections. This treatment leads to improved clinical symptoms, reduced inflammatory responses, decreased pain intensity, and enhanced quality of life while maintaining safety.

8.
Light Sci Appl ; 12(1): 259, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37899419

RESUMO

The conjugated mode of bound states in a continuum is integrated as a narrowband wavelength extraction unit. A low-cost and easy-to-prepare strategy, using solution-processable semiconductors, has been demonstrated to form a new platform for on-chip spectral analysis.

9.
Sci Bull (Beijing) ; 68(19): 2247-2267, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37659909

RESUMO

Perovskite solar cells (PSCs) have achieved remarkable progress in the past decade and become the most powerful challenger of traditional silicon photovoltaics. Among the many designs, bifacial PSCs have received widespread attention these days due to their ability to fully utilize environmental reflection and scattering light to enhance energy yield. They also can provide better aesthetic design for building-integrated photovoltaics (BIPVs). However, the potential of bifacial PSCs is not limited to these traditional applications. Importantly, such architecture also serves as a universal component for multi-junction cells and photon engineering, which are both critical for further efficiency improvement. In this review, the requirements of different functional layers under various applications are described in detail, starting from the structure of bifacial PSCs. The application developments are introduced, including albedo utilization, semitransparent PSCs (ST-PSCs), TSCs. The present issues (such as stability, large area, recombination of carriers at the back electrode and toxicity etc.) and the extra challenges of bifacial PSCs are highlighted. It is hoped that this review can provide new ideas for the future development and further improve the competitiveness of PSCs.

10.
Small Methods ; 7(11): e2300479, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37653642

RESUMO

The extensive applications of spectrum analysis across various fields have rendered the traditional desktop spectrometers unable to meet the market demand for portability and instantaneity. Reducing the size of spectrometers has become a topic of interest. Based on this trend, a novel type of computational spectrometer is developed and has been widely studied owing to its unique features. Such spectrometers do not need to integrate complex mechanical or optical structures, and most of them can achieve spectrum analysis by the properties of the material itself combines with the reconstruction algorithm. Impressively, a single-detector computational spectrometer has recently been successfully realized based on in situ modulation of material properties. This not only enables the further miniaturization of the device, but also means that the footprint-resolution limitation which has always existed in the field of hyperspectral imaging has been broken, opening a new era of image analysis. This review summarizes the classifications and principles of various spectrometers, compares the spectrum resolution performances of different types of spectrometers, and highlights the progress of computational spectrometers, especially the revolutionary single-detector spectrometer. It is expected that this review will provide a positive impact on expanding the boundary of spectrum analysis and move hyperspectral imaging forward.

11.
Front Microbiol ; 14: 1111516, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36910197

RESUMO

Plantaricin is a kind of bacteriocin with broad-spectrum antibacterial activity on several food pathogens and spoilage microorganisms, showing potential in biopreservation applications. However, the low yield of plantaricin limits its industrialization. In this study, it was found that the co-culture of Wickerhamomyces anomalus Y-5 and Lactiplantibacillus paraplantarum RX-8 could enhance plantaricin production. To investigate the response of L. paraplantarum RX-8 facing W. anomalus Y-5 and understand the mechanisms activated when increasing plantaricin yield, comparative transcriptomic and proteomic analyses of L. paraplantarum RX-8 were performed in mono-culture and co-culture. The results showed that different genes and proteins in the phosphotransferase system (PTS) were improved and enhanced the uptake of certain sugars; the key enzyme activity in glycolysis was increased with the promotion of energy production; arginine biosynthesis was downregulated to increase glutamate mechanism and then promoted plantaricin yield; and the expression of several genes/proteins related to purine metabolism was downregulated and those related to pyrimidine metabolism was upregulated. Meanwhile, the increase of plantaricin synthesis by upregulation of plnABCDEF cluster expression under co-culture indicated that the PlnA-mediated quorum sensing (QS) system took part in the response mechanism of L. paraplantarum RX-8. However, the absence of AI-2 did not influence the inducing effect on plantaricin production. Mannose, galactose, and glutamate were critical metabolites and significantly simulate plantaricin production (p < 0.05). In summary, the findings provided new insights into the interaction between bacteriocin-inducing and bacteriocin-producing microorganisms, which may serve as a basis for further research into the detailed mechanism.

12.
Oral Radiol ; 39(2): 266-274, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-35771318

RESUMO

OBJECTIVE: The purpose of this study was to investigate the prevalence and relevant factors of taurodontism in North China. METHODS: We retrospectively analysed the cone beam computed tomography (CBCT) of 1025 patients (496 male and 529 female) aged between 10 and 59 years. The crown-body/root (CB/R) ratios of the maxillary and mandibular molars were measured. The prevalence of hypotaurodontism, mesotaurodontism, and hypertaurodontism was then calculated and the incidence of taurodontism along with its relevant factors, was evaluated. RESULTS: The overall rate of taurodontism in North China was as high as 78.9%. If the third molars (opsigenes) were excluded, which have a big morphological variation from each other, the rate was 52.4%. The mean CB/R ratio of taurodontism differs from tooth position: maxillary mandibular third molars > maxillary third molars > maxillary second molars > maxillary first molars > mandibular second molars > mandibular first molars (P < 0.05). In addition, the 1025 patients were divided into different age groups, and it was found that the mean CB/R ratio decreased with age (P < 0.05). Moreover, the CB/R ratio of the mandibular first and second molars in female patients was higher than males (P < 0.05). CONCLUSION: This study revealed that taurodontism is widely prevalent in North China. The incidence of taurodontism increases the closer the tooth is to the back end of the dental arch, and quite a few of the maxillary and mandibular third molars teeth have tapered roots. And the taurodontism is decreased by age, as there were more affected female than male patients.


Assuntos
Raiz Dentária , Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Estudos Retrospectivos , Prevalência , Raiz Dentária/diagnóstico por imagem , China/epidemiologia
13.
Front Plant Sci ; 14: 1302417, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38162305

RESUMO

Schisandrae Sphenantherae Fructus (SSF), the dry ripe fruit of Schisandra sphenanthera Rehd. et Wils., is a traditional Chinese medicine with wide application potential. The quality of SSF indicated by the composition and contents of secondary metabolites is closely related to environmental factors, such as regional climate and soil conditions. The aims of this study were to predict the distribution patterns of potentially suitable areas for S. sphenanthera in China and pinpoint the major environmental factors influencing its accumulation of medicinal components. An optimized maximum entropy model was developed and applied under current and future climate scenarios (SSP1-RCP2.6, SSP3-RCP7, and SSP5-RCP8.5). Results show that the total suitable areas for S. sphenanthera (179.58×104 km2) cover 18.71% of China's territory under the current climatic conditions (1981-2010). Poorly, moderately, and highly suitable areas are 119.00×104 km2, 49.61×104 km2, and 10.98×104 km2, respectively. The potentially suitable areas for S. sphenanthera are predicted to shrink and shift westward under the future climatic conditions (2041-2070 and 2071-2100). The areas of low climate impact are located in southern Shaanxi, northwestern Guizhou, southeastern Chongqing, and western Hubei Provinces (or Municipality), which exhibit stable and high suitability under different climate scenarios. The contents of volatile oils, lignans, and polysaccharides in SSF are correlated with various environmental factors. The accumulation of major secondary metabolites is primarily influenced by temperature variation, seasonal precipitation, and annual precipitation. This study depicts the potential distribution of S. sphenanthera in China and its spatial change in the future. Our findings decipher the influence of habitat environment on the geographical distribution and medicinal quality of S. sphenanthera, which could have great implications for natural resource conservation and artificial cultivation.

14.
Biomimetics (Basel) ; 7(4)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36412709

RESUMO

In order to improve the slope movement stability and flexibility of quadruped robot, a theoretical design method of a flexible spine of a robot that was based on bionics was proposed. The kinematic characteristics of the spine were analyzed under different slopes with a Saanen goat as the research object. A Qualisys track manager (QTM) gait analysis system was used to obtain the trunk movement of goats under multiple slopes, and linear time normalization (LTN) was used to calibrate and match typical gait cycles to characterize the goat locomotion gait under slopes. Firstly, the spatial angle changes of cervical thoracic vertebrae, thoracolumbar vertebrae, and lumbar vertebrae were compared and analyzed under 0°, 5°, 10°, and 15° slopes, and it was found that the rigid and flexible coupling structure between the thoraco-lumbar vertebrae played an obvious role when moving on the slope. Moreover, with the increase in slope, the movement of the spine changed to the coupling movement of thoraco-lumbar coordination movement and a flexible swing of lumbar vertebrae. Then, the Gaussian mixture model (GMM) clustering algorithm was used to analyze the changes of the thoraco-lumbar vertebrae and lumbar vertebrae in different directions. Combined with anatomical knowledge, it was found that the motion of the thoraco-lumbar vertebrae and lumbar vertebrae in the goat was mainly manifested as a left-right swing in the coronal plane. Finally, on the basis of the analysis of the maximin and variation range of the thoraco-lumbar vertebrae and lumbar vertebrae in the coronal plane, it was found that the coupling motion of the thoraco-lumbar cooperative motion and flexible swing of the lumbar vertebrae at the slope of 10° had the most significant effect on the motion stability. SSE, R2, adjusted-R2, and RMSE were used as evaluation indexes, and the general equations of the spatial fitting curve of the goat spine were obtained by curve fitting of Matlab software. Finally, Origin software was used to obtain the optimal fitting spatial equations under eight movements of the goat spine with SSE and adjusted-R2 as indexes. The research will provide an idea for the bionic spine design with variable stiffness and multi-direction flexible bending, as well as a theoretical reference for the torso design of a bionic quadruped robot.

15.
Animals (Basel) ; 12(20)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36290256

RESUMO

We investigated the effects of fermenting the plant fraction of a solid complete feed (FPFF) on the growth performance, nutrient utilization, meat quality, antioxidant status, and intestinal microbiota of broiler chickens. The plant-based fraction of the complete feed was fermented using Lactobacillus and Bacillus subtilis. A total of 240, 1-day-old male Arbor Acres broilers were randomly allocated into four treatment groups, each comprised of six replicates. The groups were fed a corn-soybean meal-based diet (basic diet) or the same diet supplemented with 5%, 10%, or 15% FPFF for 6 weeks. As results, adding 10% fermented feed significantly improved the growth performance in 1-21 days, and adding 5% fermented feed significantly improved the growth performance in 1-42 days. Adding 15% fermented feed significantly improved the metabolic rate of the birds in 19-21 days and significantly increased the monounsaturated fatty acid concentration in the chickens. Adding fermented feed significantly reduced the cholesterol content in the chickens. In conclusion, adding 10% fermented feed significantly reduced the feed conversion ratio in 1-21 days and adding 5% fermented feed significantly improved the average daily gain and the average daily feed intake in 1-42 days. In addition, consuming fermented feed improved the meat quality of broilers.

16.
Biomimetics (Basel) ; 7(4)2022 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-36278717

RESUMO

The goose's neck is an excellent stabilizing organ with its graceful neck curves and flexible movements. However, the stabilizing mechanism of the goose's neck remains unclear. This study adopts a dynamic in vivo experimental method to obtain continuous and accurate stable motion characteristics of the goose's cervical vertebra. Firstly, the results showed that when the body of a goose was separately moved back and forth along the Y direction (front and back) and Z direction (up and down), the goose's neck can significantly stabilize the head. Then, because of the limitation of the X-ray imaging area, the three-dimensional intervertebral rotational displacements for vertebrae C4-C8 were obtained, and the role that these five segments play in the stabilization of the bird's neck was analyzed. This study reveals that the largest range of the adjacent vertebral rotational movement is around the X-axis, the second is around the Y-axis, and the smallest is around the Z-axis. This kinematic feature is accord with the kinematic feature of the saddle joint, which allows the flexion/around X-axis and lateral bending/around Y-axis, and prevents axial rotation/around Z-axis.

17.
J Interv Cardiol ; 2022: 9057832, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36311279

RESUMO

Background: Intermediate coronary stenosis (ICS) is defined as a visually estimated percentage of diameter stenosis ranging between 40% and 70% by conventional coronary angiography (CAG). Whether to perform percutaneous coronary intervention (PCI) for these lesions is a challenge in clinical practice. The fractional flow reserve (FFR) can guide treatment by determining the functional significance of ICS. Studies have shown that some clinical indicators can be used to predict FFR. However, there is little research on this in the Chinese population. Methods: We retrospectively analyzed 690 patients who underwent FFR measurements to determine the functional significance of a single ICS. Patients were divided into 2 groups: FFR ≤0.8 (n = 280) and FFR >0.8 (n = 410). We compared the clinical factors between the two groups and performed multivariate logistic regression analyses to explore the risk factors. In addition, receiver-operating characteristic (ROC) curves were constructed for FFR ≤0.8 diagnoses. Results: The mean UHR (uric acid to high-density lipoprotein cholesterol ratio) level was significantly higher in the FFR ≤0.8 group (p < 0.001). UHR corrects negatively with FFR (r = -0.44, p < 0.001). High-level UHR was an independent risk factor for the FFR ≤0.8 (OR = 7.17, 95% CI 4.17-12.34). The area under the curve (AUC) of the UHR diagnostic capacity for the FFR ≤0.8 is 0.77, with 77.3% sensitivity and 68.2% specificity. Conclusion: UHR levels were significantly increased in patients with hemodynamically significant coronary lesions. UHR is a novel predictor of functionally significant lesions in patients with a single-vessel disease of ICS.


Assuntos
Estenose Coronária , Reserva Fracionada de Fluxo Miocárdico , Intervenção Coronária Percutânea , Humanos , Ácido Úrico , Estudos Retrospectivos , HDL-Colesterol , Sensibilidade e Especificidade , Estenose Coronária/diagnóstico , Angiografia Coronária , Curva ROC , Índice de Gravidade de Doença , Valor Preditivo dos Testes
18.
Aging (Albany NY) ; 14(14): 5699-5709, 2022 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-35896004

RESUMO

Previous studies have shown that aging promotes myocardial apoptosis. However, the detailed mechanisms remain unclear. Our recent studies revealed that aging not only activates apoptosis, but also activates some anti-apoptotic factors. By quantitative phosphoproteomics, here we demonstrated that aging increases cytochrome c (Cytc) phosphorylation at threonine 50 (T50), a post-translational modification with unknown functional impact. With point mutation and lentivirus transfection, cardiomyocytes were divided into four groups: empty vector group, WT (wild type), T50E (as a phosphomimic variant), and T50A (non-phosphorylatable). TUNEL staining and flow cytometry were used to determine the apoptosis ratio in different groups after hypoxic/reoxygenated (H/R) treatment. The results showed that T50-phosphorylated Cytc suppressed myocardial apoptosis induced by H/R. Furthermore, Western Blot and ELISA measurements revealed that Cytc T50 phosphorylation inhibited caspase-9 and caspase-3 activity without altering caspase-8, BCL-2, BCL-XL, and Bax expression. In our study, we demonstrated that aging increases phosphorylation Cytc at T50 and this aging-increasing phosphorylation site can suppress H/R-induced apoptosis.


Assuntos
Citocromos c , Treonina , Envelhecimento , Apoptose , Citocromos c/genética , Citocromos c/metabolismo , Humanos , Hipóxia/metabolismo , Miócitos Cardíacos/metabolismo , Fosforilação , Treonina/metabolismo
19.
Adv Mater ; 34(33): e2200221, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35706366

RESUMO

There are significant applications for miniature on-chip spectrometers in many fields. However, at present, on-chip spectrometers have to utilize an integrated strategy to achieve spectral analysis, which undoubtedly squanders the photosensitive area and adds pressure to the miniaturization of the spectrometer. Here, a unique spectrometer design that adopts a single detection point with in situ modulation realized by the photogain control at various bias voltages is demonstrated. With micrometer-level footprints, this single-dot spectrometer processes a resolution of about 5 nm and a response time down to about 197 µs. This is the first in situ perovskite modulation strategy that breaks the footprint-resolution restriction of spectrum analysis and demonstrates a new design direction for functional perovskite devices.

20.
Adv Mater ; 34(23): e2200041, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35332958

RESUMO

Preparation of high-performance perovskite solar cells without strict environmental control is an inevitable trend of commercialization. Humidity is considered the main factor hindering perovskite performance. Formamidine (FA)-based perovskites suffer from the instability of photoactive black α-FAPbI3, especially in humid air, and numerous defects in the surface and bulk of perovskite films limit their performance. In this work, long-chain n-heptylamine (nHA) is introduced via antisolvent engineering into an FA-based perovskite film. nHA removes the negative intermediate adduct and promotes the formation of α-FAPbI3 at room temperature in humid air via intermolecular exchange behavior. Moreover, the existence of nHA in the final perovskite film also reduces the defects and suppresses ion migration. The champion device delivers a power conversion efficiency (PCE) of 23.7% (certificated 22.76%) with negligible hysteresis, and the fabricated devices exhibit superior reproductivity. The device stability is also enhanced, maintaining 95% of its initial PCE after 1500 h in ambient air. Moreover, the PCE has no attenuation at the maximum power point under continuous 1-sun light soaking for 500 h. The universality of this method is also demonstrated by other perovskite compositions, including methylamine lead iodine (MAPbI3 ) and FAx MA1- x PbI3 in humid air.

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