Photoelectric Process Research Articles

In Situ Photoelectrochemical‐Induced Surface Reconstruction of BiVO4 Photoanodes for Solar Fuel Production

BiVO4 has been widely concerned due to its great potential in photoelectrochemical (PEC) water splitting. However, low carrier mobilities and high recombination efficiency of photogenerated carriers impede its photocatalytic performance. Herein, an in situ PEC cyclic‐voltammetry‐induced surface reconstruction of BiVO4 photoanodes (BVO pristine) is developed with significantly enhanced efficiency for solar water splitting. A series of in situ characterizations (including in situ X‐ray diffraction, in situ Raman), together with electrochemical tests and density‐functional theory calculations, reveal that during the photoelectrical activation process, the BVO pristine surfaces undergo a crystal plane reconstruction with greatly increased {040} crystal face to promote the separation of photogenerated carriers. In addition, abundant vanadium vacancies and oxygen vacancies are also introduced into the BiVO4 surface during the crystal face reconstruction process with more favorable surface water adsorption and increased injection efficiency of photogenerated carriers. Therefore, the charge‐transfer resistance (Rct) between BVO pristine and electrolyte under AM 1.5G illumination substantially reduced from the original 15 200 to 2820 Ω after the activation. Moreover, the photocurrent density of activated BVO pristines increases more than 12 times, relative to the original BiVO4. In this work, a new horizon for in situ photoelectric activation of semiconductor photoelectrodes with significantly enhanced PEC water splitting is provided.

Optoelectronic synapses with chemical-electric behaviors in gallium nitride semiconductors for biorealistic neuromorphic functionality

Optoelectronic synapses, leveraging the integration of classic photo-electric effect with synaptic plasticity, are emerging as building blocks for artificial vision and photonic neuromorphic computing. However, the fundamental working principles of most optoelectronic synapses mainly rely on physical behaviors while missing chemical-electric synaptic processes critical for mimicking biorealistic neuromorphic functionality. Herein, we report a photoelectrochemical synaptic device based on p-AlGaN/n-GaN semiconductor nanowires to incorporate chemical-electric synaptic behaviors into optoelectronic synapses, demonstrating unparalleled dual-modal plasticity and chemically-regulated neuromorphic functions through the interplay of internal photo-electric and external electrolyte-mediated chemical-electric processes. Electrical modulation by implementing closed or open-circuit enables switching of optoelectronic synaptic operation between short-term and long-term plasticity. Furthermore, inspired by transmembrane receptors that connect extracellular and intracellular events, synaptic responses can also be effectively amplified by applying chemical modifications to nanowire surfaces, which tune external and internal charge behaviors. Notably, under varied external electrolyte environments (ion/molecule species and concentrations), our device successfully mimics chemically-regulated synaptic activities and emulates intricate oxidative stress-induced biological phenomena. Essentially, we demonstrate that through the nanowire photoelectrochemical synapse configuration, optoelectronic synapses can be incorporated with chemical-electric behaviors to bridge the gap between classic optoelectronic synapses and biological synapses, providing a promising platform for multifunctional neuromorphic applications.

Light-Cured Junction Formation and Broad-Band Imaging Application in Thermally Mismatched van der Waals Heterointerface.

Van der Waals (vdW) heterostructures are mainly fabricated by a classic dry transfer procedure, but the interface quality is often subject to the vdW gap, residual strains, and defect species. The realization of interface fusion and repair holds significant implications for the modulation of multiple photoelectric conversion processes. In this work, we propose a thermally mismatched strategy to trigger broad-band and high-speed photodetection performance based on a type-I heterostructure composed of black phosphorus (BP) and FePS3 (FPS) nanoflakes. The BP acts as photothermal source to promote interface fusion when large optical power is adopted. The regulation of optical power enables the device from pyroelectric (PE) and/or alternating current photovoltaic (AC-PV) mode to a mixed photovoltaic (PV)/photothermoelectric (PTE)/PE mode. The fused heterostructure device presents an extended detection range (405~980 nm) for the FPS. The maximum responsivity and detectivity are 329.86 mA/W and 6.95 × 1010 Jones, respectively, and the corresponding external quantum efficiency (EQE) approaches ~100%. Thanks to these thermally-related photoelectric conversion mechanism, the response and decay time constants of device are as fast as 290 μs and 265 μs, respectively, superior to current all FPS-based photodetectors. The robust environmental durability also renders itself as a high-speed and broad-band imaging sensor.

Ag-TiO2 Photovoltaic Synergistic Field-catalyzed Degradation Performance of Tetracycline

Background: Tetracycline (TC), a commonly used antibiotic, is extensively utilized in the medical sector, leading to a significant annual discharge of tetracycline effluent into the water system, which harms both human health and the environment. Objective: A novel technique was developed to address the issues of photogenerated carrier complexation and photocatalyst immobilization. Compared to traditional photocatalytic photoelectrodes, the suspended catalyst used in the photovoltaic synergy field is more stable and increases the solidliquid contact area between the catalyst and the pollutant. Methods: This paper uses sol-gel-prepared Ag-TiO2 materials for the photoelectric synergistic fieldcatalyzed degradation of TC. The study examined how the Ag doping ratio, calcination conditions, catalyst injection, pH, electrolytes, and electrolyte injection affected photoelectric synergistic fieldcatalyzed degradation. The experiments were performed in a photocomposite field with a constant 50 mA current and a 357 nm UV lamp for 60 minutes. The composites underwent characterization using XRD, TEM, and XPS techniques. Results: Ag-TiO2 photoelectric synergistic field-catalyzed reaction with 357 nm ultraviolet lamp irradiation for 60 min and a constant current of 50 mA degraded 5 mg/LTC under preparation conditions of molar doping ratio of Ti: Ag=100:0.5, roasting temperature of 500 °C, and roasting time of 2 h. The photoelectric synergistic field-catalyzed degradation process achieved a degradation rate of 90.49% for 5 mg/L TC, surpassing the combined degradation rates of electrocatalysis and photocatalysis. The quenching experiments demonstrated that the degradation rate of TC decreased from 90.49% in the absence of a quencher to 53.23%, 42.58%, and 74.52%. The presence of •OH had a more significant impact than h+ and •O2 -. Conclusion: The findings suggest that Ag-TiO2 significantly enhanced the efficacy of photoelectric synergistic field-catalyzed degradation and can be employed to treat high-saline and lowconcentration TC. This establishes a benchmark for using photoelectrocatalytic materials based on titanium in treating organic wastewater.

Thickness-derived optical-electrical management in Sn-based perovskite solar cells

Tin-based perovskite solar cells (TPSCs) have attracted great attention due to their promising photovoltaic performance and environmental friendliness. Adequate photon trapping and efficient carrier utilization are known to be the keys to achieving high-performance devices, which are closely related to the thickness of the light-absorbing layer and the quality of film formation, respectively. Due to the ultra-fast crystallization characteristics and low defect formation energy, thick tin-based perovskite films are faced with poor electrical performance due to poor quality. Thin tin-based perovskite films are easy to achieve low defects and high crystallization quality, but insufficient thickness leads to the problem of insufficient light trapping. To address these issues, we have thoroughly investigated the various aspects of the photoelectric conversion process in TPSC devices and, for the first time, explored the behavior of front-end optical field management. It is found that the self-constructed microcavity effect can effectively improve the light trapping efficiency under the premise that a thin light-absorbing layer is used, so that sufficient photon trapping and excellent carrier transport characteristics can be ensured simultaneously to realize a high-performance device. Different from the traditional film formation and defect modulation strategy, the present work provides a feasible idea for the performance enhancement of TPSC devices, and is also of great significance for cost control and environmental protection issues in commercial applications.

Pyroelectric effect in high detectivity self-powered photodetector based on Cs2AgBiBr6

The ferroelectric perovskite material Cs2AgBiBr6 has received much attention because of its low poisonous nature and environmental stability. In this paper, we prepared high-quality Cs2AgBiBr6 thin films for self-powered photodetectors using a low-pressure-assisted method, investigated their optical, electrical, and pyroelectric properties, and characterized the film morphology and crystallization. The device modulates the photoelectric process without an external power supply, and has a maximum switching ratio of 1.72 × 106, a response rate of 0.158 A/W, a specific detectivity of 1.39 × 1011 Jones, an external quantum efficiency of 52.8 %, and a fast response time of 15.4/16.8 μs when irradiated with 532 nm light, which is much better than that of previous self-powered devices with the same material on/off ratio and specific detectivity. It is worth mentioning that the pyroelectric effect was observed in the infrared band. In addition, the devices exhibited high stability to water and oxygen in an air environment (25 °C, 60 % humidity), retaining more than 95 % of the initial performance after one month of placement. Our study demonstrates that the lead-free perovskite Cs2AgBiBr6 is a promising and environmentally friendly alternative for the preparation of highly stable self-powered photodetectors and is also of great research value in the field of pyroelectric detection.

Chlorophyll a acts as a natural photosensitizer to drive nitrate reduction in nonphotosynthetic microorganisms

With the death and decomposition of widely distributed photosynthetic organisms, free natural pigments are often detected in surface water, sediment and soil. Whether free pigments can act as photosensitizers to drive biophotoelectrochemical metabolism in nonphotosynthetic microorganisms has not been reported. In this work, we provide direct evidence for the photoelectrophic relationship between extracellular chlorophyll a (Chl a) and nonphotosynthetic microorganisms. The results show that 10 μg of Chl a can produce significant photoelectrons (∼0.34 A/cm2) upon irradiation to drive nitrate reduction in Shewanella oneidensis. Chl a undergoes structural changes during the photoelectric process, thus the ability of Chl a to generate a photocurrent decreases gradually with increasing illumination time. These changes are greater in the presence of microorganisms than in the absence of microorganisms. Photoelectron transport from Chl a to S. oneidensis occurs through a direct pathway involving the cytochromes MtrA, MtrB, MtrC and CymA but not through an indirect pathway involving riboflavin. These findings reveal a novel photoelectrotrophic linkage between natural photosynthetic pigments and nonphototrophic microorganisms, which has important implications for the biogeochemical cycle of nitrogen in various natural environments where Chl a is distributed.

An integrated, multi-functional intrinsic responsive foldable protective layer for space station solar panels

The functionalized foldable protective layer proficiently alleviates the potential detriment endured by space station solar panels due to prolonged and uninterrupted exposure to the environment. Soft actuators demonstrate significant value in foldable protective layers due to their intrinsic response characteristics and programmability. However, current soft actuators still struggle to meet the requirements of work stability and scene applicability in the space environment. A PMT (Polydimethylsiloxane (PDMS)/Multi-walled carbon nanotubes (MWCNTs)-Thermoplastic polyimides (TPI)) soft actuator was proposed to address this issue in this paper. The PMT soft actuators exhibit strong interlayer interfacial adhesion, stable physical and chemical performance, and excellent mechanical performance. Notably, the PMT soft actuators can sense thermal, electric fields, infrared light, and mechanical force simultaneously with only one active layer. Furthermore, analytical models were calibrated to provide predictions, and the thermal and photoelectric actuation processes of PMT soft actuators with different structures and application scenes were predicted accurately. The experimental results validated the application value of PMT actuators as foldable protective layers for space station solar panels. The preparation, testing, application, and model construction of the PMT system provide new research ideas and development opportunities for the practical application of functional polymers in intelligent sensing and actuation systems.

Real-time generation of circular patterns in electron beam lithography

Electron beam lithography (EBL) involves the transfer of a pattern onto the surface of a substrate by first scanning a thin layer of organic film (called resist) on the surface by a tightly focused and precisely controlled electron beam (exposure) and then selectively removing the exposed or nonexposed regions of the resist in a solvent (developing). It is widely used for fabrication of integrated circuits, mask manufacturing, photoelectric device processing, and other fields. The key to drawing circular patterns by EBL is the graphics production and control. In an EBL system, an embedded processor calculates and generates the trajectory coordinates for movement of the electron beam, and outputs the corresponding voltage signal through a digital-to-analog converter (DAC) to control a deflector that changes the position of the electron beam. Through this procedure, it is possible to guarantee the accuracy and real-time control of electron beam scanning deflection. Existing EBL systems mostly use the method of polygonal approximation to expose circles. A circle is divided into several polygons, and the smaller the segmentation, the higher is the precision of the splicing circle. However, owing to the need to generate and scan each polygon separately, an increase in the number of segments will lead to a decrease in the overall lithography speed. In this paper, based on Bresenham’s circle algorithm and exploiting the capabilities of a field-programmable gate array and DAC, an improved real-time circle-producing algorithm is designed for EBL. The algorithm can directly generate circular graphics coordinates such as those for a single circle, solid circle, solid ring, or concentric ring, and is able to effectively realizes deflection and scanning of the electron beam for circular graphics lithography. Compared with the polygonal approximation method, the improved algorithm exhibits improved precision and speed. At the same time, the point generation strategy is optimized to solve the blank pixel and pseudo-pixel problems that arise with Bresenham’s circle algorithm. A complete electron beam deflection system is established to carry out lithography experiments, the results of which show that the error between the exposure results and the preset patterns is at the nanometer level, indicating that the improved algorithm meets the requirements for real-time control and high precision of EBL.

Interfacial Mass Diagnostics: Quantitative Perspective on Construction and Mechanism Understanding of Dye-Sensitized, Perovskite and Quantum Dots Solar Cells.

Dye-sensitized solar cells (DSSCs), quantum dot-sensitized solar cells (QDSSCs) and perovskite solar cells (PSCs) have attracted wide attention. DSSCs, QDSSCs and PSCs can be prepared by liquid phase or solid phase, which causes a certain range of interface micro-mass changes during preparation. In addition, the photoelectric conversion process occurring inside the device also inevitably causes interface micro-mass changes. Interpretation of these interface micro-mass changes can help to optimize the cell structure, improve the stability and performance repeatability of the device, as well as directly or indirectly infer, track and predict the internal photoelectric conversion mechanism of the device. Quartz crystal microbalance (QCM) is a powerful tool for studying surface mass changes, extending this technology to the fields of solar cells to directly obtain interface micro-mass changes, which makes the research more in-depth and opens up a new perspective for explaining the basic principles of solar cells. This review summarizes the research progress of QCM application in DSSCs, QDSSCs and PSCs in recent years, and explores the challenges and new opportunities of QCM application in new solar cells in the future.

Research on interference compensation methods for color image sensors based on iterative learning

PurposeFixed mode noise and random mode noise always exist in the image sensor, which affects the imaging quality of the image sensor. The charge diffusion and color mixing between pixels in the photoelectric conversion process belong to fixed mode noise. This study aims to improve the image sensor imaging quality by processing the fixed mode noise.Design/methodology/approachThrough an iterative training of an ergoable long- and short-term memory recurrent neural network model, the authors obtain a neural network model able to compensate for image noise crosstalk. To overcome the lack of differences in the same color pixels on each template of the image sensor under flat-field light, the data before and after compensation were used as a new data set to further train the neural network iteratively.FindingsThe comparison of the images compensated by the two sets of neural network models shows that the gray value distribution is more concentrated and uniform. The middle and high frequency components in the spatial spectrum are all increased, indicating that the compensated image edges change faster and are more detailed (Hinton and Salakhutdinov, 2006; LeCun et al., 1998; Mohanty et al., 2016; Zang et al., 2023).Originality/valueIn this paper, the authors use the iterative learning color image pixel crosstalk compensation method to effectively alleviate the incomplete color mixing problem caused by the insufficient filter rate and the electric crosstalk problem caused by the lateral diffusion of the optical charge caused by the adjacent pixel potential trap.

Rational molecular engineering towards efficient heterojunction solar cells based on organic molecular acceptors

The selection of photoactive layer materials for organic solar cells (OSCs) is essential for the photoelectric conversion process. It is well known that chlorophyll is an abundant pigment in nature and is extremely valuable for photosynthesis. However, there is little research on how to improve the efficiency of chlorophyll-based OSCs by matching chlorophyll derivatives with excellent non-fullerene acceptors to form heterojunctions. Therefore in this study we utilize a chlorophyll derivative, Ce6Me3, as a donor material and investigate the performance of its heterojunction with acceptor materials. Through density functional theory, the photoelectric performances of acceptors, including the fullerene derivative PC71BM and the terminal halogenated non-fullerene DTBCIC series, are compared in detail. It is found that DTBCIC-Cl has better planarity, light absorption, electron affinity, charge reorganization energy and charge mobility than others. Ce6Me3 has good energy level matching and absorption spectral complementarity with the investigated acceptor molecules and also shows good electron donor properties. Furthermore, the designed Ce6Me3/DTBCIC interfaces have improved charge separation and reorganization rates (K CS/K CR) compared with the Ce6Me3/PC71BM interface. This research provides a theoretical basis for the design of photoactive layer materials for chlorophyll-based OSCs.

A signal-on photoelectrochemical sensor based on the target-triggered double-ion exchange reaction for Hg2+ under visible light

A photoelectrochemical (PEC) sensor driven by visible light has been developed to detect Hg2+ with a signal output "turn-on" mode on basic of the double ZIF-Cds@Zns@HgS type-II heterojunction formed by a target-triggered double-ion exchange reaction. The type-II heterojunction photocatalysts ZIF-CdS@ZnS were prepared through growing ZnS nanoparticles onto ZIF-CdS hollow nanocages which were innovatively synthesized using ZIF-67 as a template by MOF-engaged directional deposition strategy. An obvious photocurrent amplification effect induced by mercury ions is evident in ZIF-CdS@ZnS modified ITO electrodes, compared to ZIF-CdS or pure ZnS modified electrodes. The ZIF-CdS@ZnS heterojunction would successfully utilize visible light to promote the photoelectric response process due to the synergistic effect of the narrow band gap component and cavity structure. More importantly, the photocurrent can be greatly amplified by the target-triggered double-ion exchange reaction, which results in the generation of double type-II heterostructures HgS@ZnS@CdS, where an electrical field resulting from the unification of the fermi level facilitates the separation of photogenerated charges and increases the output photocurrent. Besides, the target-triggered double ion exchange strategy can provide guidance for the design of signal-on PEC sensors to detect other heavy metal ions sensitively.

Research on phosphorite photoelectric sorting process based on fuzzy algorithm

Abstract In this paper, we synthesize the differences in grayscale and texture information of phosphorite X-ray images and extract a total of six feature quantities under their grayscale and texture features, respectively. After feature fusion, a fuzzy support vector machine classifier with a normal plane-type affiliation function is used to optimize the binary classification method of traditional support vector machines, which improves the accuracy of classification. To improve the sorting model’s division of the optimal classification hyperplane, the centroid position of the two types of samples is considered comprehensively. In order to give full play to the classification performance of the sorting model, the particle swarm algorithm is further used to optimize the core parameters of the fuzzy support vector machine, the penalty factor, and the kernel parameters to complete the construction of the classifier model. In the face of the mixed colloidal phosphorite that can not be exploited, based on the PSO-NP-FSVM photoelectric sorting operation, the concentrate yield rate, operation recovery rate, and optical sorting waste rate are 56.52%, 20.87%, and 71.17%, respectively. After photoelectric sorting, the grade of concentrate P2 O5 can be increased to 20.98%, which can meet the requirements for the grade of the processing plant. Therefore, the photoelectric sorting process combined with a fuzzy algorithm is capable of meeting the actual production requirements.

Charge photogeneration and recombination dynamics in non-fullerene solar cells based on a polymer donor with a mono-fluorinated π-bridge.

Non-symmetric fluorine substitution is an important route for designing π-conjugated polymers for high-performance solar cells. However, excited state dynamics in a non-symmetric fluorinated polymer and solar cells are poorly understood. In this work, excited state dynamics in a neat mono-fluorinated polymer (PTzBI-dF) film and blend films (PTzBI-dF:Y6) were studied using time-resolved spectroscopy. For the neat donor film, we found the activation energy of the PTzBI-dF film transiting from radiative states to non-radiative states to be ∼58 meV. Besides, we found that both exciton diffusion coefficient and exciton diffusion length in the PTzBI-dF film are higher than those in the PTzBI-Cl film, which has no fluorinated π-bridge. The high exciton diffusion length of the PTzBI-dF film benefits from its long exciton lifetime (∼327.8 ps), which is much longer than that of the polymer donors such as P3HT and PM6. For PTzBI-dF:Y6 blend films, we found that the energy level offsets of the HOMO (0.13 eV) and LUMO (0.23 eV) are sufficient to dissociate the acceptor and donor excitons, respectively. Besides, we found that carrier recombination in PTzBI-dF:Y6 and PTzBI-Cl:Y6 blend films are dominated by bimolecular recombination processes, and thermal annealing treatment has a weak influence on the charge photogeneration and recombination process of the PTzBI-dF:Y6 film at an ultrafast time scale. Thus, this work is helpful for understanding photoelectrical conversion processes in non-symmetric fluorinated polymer-based solar cells.

Achieving High External Quantum Efficiency for ITIC‐Based Organic Solar Cells with Negligible Homo Energy Offsets

AbstractMinimizing energy loss in organic solar cells (OSCS) is critical for attaining high photovoltaic performance. Among the parameters that correlated to photovoltaic performance, the energy offsets between donor–acceptor pairs play a vital role in photoelectric conversion processes. For so far reported a large number of non‐fullerene acceptors (NFAs), only Y6 and its derivatives can achieve external quantum efficiencies (EQEs) over 80% with negligible energy offsets when combined with polymeric donors. Thus, understanding the relationship between energy offsets and energy losses in representative NFAs is the key to further enhancing the efficiency of OSCs. In this study, a series of wide‐bandgap polymer donors based on pyrrolo[3,4‐f]benzotriazole‐5,7(6H)‐dione (TzBI) and benzo[1,2‐c:4,5‐c′] dithiophene‐4,8‐dione building blocks are combined with representative NFAs, including ITIC and Y6, to gain deep insights into their photovoltaic performances and related energy losses. Outstanding EQEs (≈70%) and suppressed non‐radiative recombination are achieved at negligible energy offsets. Moreover, it is noted that a prolonged exciton lifetime of acceptor is not essential to obtain high EQEs in OSCs with negligible energy offsets. Eventually, ITIC derivatives with high electroluminescence efficiencies and near‐infrared absorptions have the potential to be assembled to obtain high‐efficiency OSCs.

A solar-blind vacuum-ultraviolet photodetector based on free-standing lamellar aluminum nitride single crystal

High-quality aluminum nitride (AlN) crystals are the key material for the development of high-performance solid-state solar-blind vacuum-ultraviolet (VUV) photodetectors. However, the commonly used epitaxial method to grow AlN crystals would limit this development due to the existence of indispensable substrates. This study addresses this issue using free-standing lamellar AlN single crystals that are grown using the physical vapor transport method. The large lateral dimension of the crystal enables the construction of an Au-AlN-graphene van der Waals heterojunction, which can function as a vertical VUV photodetector with the graphene serving as the light window. The asymmetric junctions formed on the two sides of the crystal and the limited penetration of the VUV endow the device with a bias polarity-dependent photoresponse feature arising from different photoelectric processes. Furthermore, the device demonstrates a high responsivity of 5.77 A W−1 and a high specific detectivity of 1.71 × 1013 cm Hz1/2 W−1 under the illumination of a 193 nm laser. The high crystallinity of the AlN guarantees a high spectral selectivity of responsivity with a 193 nm/280 nm rejection ratio of 3 × 102. This work would inspire the development of wide-bandgap-semiconductor-based VUV photodetectors in terms of methodology and mechanism.

Performance investigation on a concentrating photovoltaic thermal system integrated with spectral splitter and absorption heat pump

To alleviate the energy consumption crisis and environmental pollutant problems, a concentrating photovoltaic thermal system integrated with spectral splitter and absorption heat pump is proposed. Through solar spectral splitting, the photo-electric and photo-thermal processes are decoupled, which facilitates the cogeneration of electricity and high-temperature heat. Through absorption heat pump, the temperature of geothermal energy is improved by high-temperature solar heat for subsequent utilization. Thus, the efficient utilization of full spectrum solar energy is achieved. To further evaluate the performances, an electric-thermal coupled model is developed and the comprehensive analysis is carried out from energy, exergy and exergoeconomic viewpoints. Results indicate that for an optical window of 400–1300 nm, strong LiBr/H2O solution concentration of 64 %, concentration difference of 5 % and thermal receiver temperature of 438.15 K, the overall energy and exergy efficiency is obtained about 102.14 % and 37.49 %, respectively. Among all components, parabolic trough concentrator is the most inefficient component with energy losses of 123.86 MWh. Highest exergy destruction is observed in the solar cell, accounting for 67.51 % of the total destruction. Moreover, a total exergoeconomic factor of 79.94 % is obtained for the entire system indicating that 20.06 % of the total costs are related to exergy destruction.

All-optical 8-QAM signal demodulator based on 2D photonic crystals

This paper proposes a novel two-dimensional photonic crystal-based 8-QAM signal demodulator with a unique combination of nonlinear cavities and line defects. It consists of chalcogenide cylinders arranged in a square lattice against an air background. The proposed structure enables 8-QAM signal demodulation in an all-optical environment. Instead of the photoelectric conversion process, the structure converts the communication signal into the corresponding optical logic signal by distinguishing the intensity and phase differences of the incident light. The performances are analyzed and calculated by using the finite difference time-domain method and the plane wave expansion method. Simulation results illustrate that the maximum response time of the demodulator is 1.067 ps, and the minimum light contrast ratio is 4.39 dB.

Self-powered photoelectrochemical immunosensor with triple enhanced photoelectric response for sensitive detection of cTnI

A self-powered photoelectrochemical (PEC) immunosensor triple enhanced photoelectric response was proposed for the sensitive cardiac troponin (cTnI) detection. The self-powered PEC platform was constructed by sulfur indium copper hollow nanocage as a photocathode and hollow nanometer sphere heterojunction (In2S3 @CdIn2S4) as a photoanode, where the coulomb force of distinct photoelectrodes as the driving force effectively improves the photoelectric response without redox-mediator or external potential. In addition, the reverse transfer of photo-generated charge carriers increases the photoelectric response capacity due to the internal electric field effect in type II heterojunction. What is more exciting is that carefully designed hollow materials playing energy conversion function possess compelling properties. Given the advantages of multiple reflection effects in the cavity, thin-shell configuration and large surface, the designed hollow materials possessed a higher photon capture rate, a shorter-range transfer for photon-generated charges, and more active site points for the associated redox reactions, which facilitated the entire photoelectric response process. Based on the above strategies, the proposed PEC immunosensor achieved triple enhanced photoelectric response to present high sensitivity for detecting cTnI. The present study has gone some way to design nanomaterials with superior photoelectric activity, which paves a way for detecting other disease markers in high sensitivity.