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The transparent device of CdS quantum dots modified Cu2O/ZnO orderly nano array p-n junction towards the enhanced photovoltaic conversion
摘要： The transparent device of CdS QDs modified Cu2O/ZnO nano array p-n junction is prepared via simple continuous magnetron sputtering method and chemical deposition. The p-n junction device with good stability exhibits decent transparency of about ~80% in visible light, and evident photovoltaic response enhancement of about ~100 times than the unmodified sample, that can be mainly attributed to the CdS QDs with high QY can improve the visible light response, the p-n junction with self-photovoltage and the ZnO order arrays can improve the transport of the photon-generated carriers.
关键词： p-n junction,CdS quantum dots,Orderly nano array,Transparent device
更新于2025-09-23 15:19:57
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Resistive-type UVa??visible photodetector based on CdS NWs /ZnO nanowalls heterostructure fabricated using in-situ synthesis method
摘要： Here, the resistivity-type UV-visible photodetectors are designed and fabricated by implementation of direct integration between CdS nanowires(NWs) and vertical standing ZnO nanowalls with a facile in-situ synthesis method, in which ZnO nanowalls are employed as good support for anchoring well-dispersed CdS NWs to overcome its random distribution. The photodetectors based on CdS/ZnO heterojunctions demonstrate higher photo response activity than the prinstine CdS NWs and pure ZnO nanowalls photodetectors . The high performance could be attributed to the charge carrier separation efficiency and fast charge transportation facilitated by effective and close contact between CdS NWs and ZnO nanowalls. The results indicate that the ZnO/CdS heterojunctions fabricated by in-situ synthesis method provide a facile approach for nanoscale optoelectronic device.
关键词： photodetector,in-situ synthesis,CdS NWs,ZnO nanowalls
更新于2025-09-23 15:19:57
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Data on the effect of CdS on the lateral collection length of charge carriers for Cu(In,Ga)Se2 solar cells with mesh transparent conducting electrodes
摘要： Mesh transparent conducting electrodes (TCEs) have been successfully employed to Cu(In,Ga)Se2 (CIGS) solar cells (Lee et al., 2018; Jang et al., 2017; Lee et al., 2020) [1-3]. Lateral motion of charge carriers is necessarily required for the carriers to be collected in CIGS solar cell cells having mesh TCEs. Lateral collection length of carriers can be obtain based on the lateral photocurrent values measured in custom designed CIGS test structures, which in turn enables to determine an optimum design of mesh TCEs for these CIGS solar cells (Lee et al., 2019) [4]. In a standard CIGS solar cell, a CdS layer is required to be fully cover the CIGS whole surface. However, it is not the case for mesh TCE based CIGS solar cells (Chung, 2019) [5]. The presence or absence of the CdS layer on the CIGS/Mo planar stack alters the traveling path of the charge carriers, which in turn will affect the lateral photocurrent values. Therefore, it will be helpful to know the effect of the presence or absence of the CdS layer on the lateral photocurrents in mesh TCE based CIGS solar cells.
关键词： Lateral collection length,CdS,CIGS,Lateral photocurrent,Solar cells,Mesh TCE
更新于2025-09-23 15:19:57
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Spin-Controlled Charge Recombination Pathways across the Inorganic/Organic Interface
摘要： Charge transfer and recombination across the inorganic/organic interface in nanocrystal or quantum dot (QD)-molecule hybrid materials has been extensively studied. Principles of controlling charge transfer and recombination via energetics and electronic coupling have been established. However, the use of electron spin to control transfer and recombination pathways in such systems remains relatively underexplored. Here we use CdS QD-alizarin (AZ) as a model system to demonstrate this principle. Using time-resolved spectroscopy, we found that the charge separated states (QD--AZ+) created by selectively exciting AZ molecules mostly recombined to regenerate ground state complexes, whereas the apparently “same” charge separated states created by exciting QDs recombined to produce AZ molecular triplet states. Such a difference can be traced to the distinct spin configurations between excited QDs (QD*, with an ill-defined spin) and AZ (1AZ*, spin singlet) and the asymmetric electron and hole spin-flip rates in II-VI group QDs. The transferability of such a principle was confirmed by similar observations obtained for CdS QD-tetracene complexes. Opening an avenue of controlling charge transfer and recombination pathways via electron spin is potentially important for applications such as artificial photosynthesis.
关键词： CdS QD-alizarin,artificial photosynthesis,quantum dot,inorganic/organic interface,triplet states,electron spin,recombination,time-resolved spectroscopy,Charge transfer
更新于2025-09-23 15:19:57
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The role of CdS doping in improving SWIR photovoltaic and photoconductive responses in solution grown CdS/PbS heterojunctions
摘要： Low cost Short Wavelength Infrared (SWIR) photovoltaic (PV) detectors and solar cells are of very great interest, yet the main production technology today is based on costly epitaxial growth of InGaAs layers. In this study, layers of p-type, quantum confined (QC) PbS nano-domains (NDs) structure that were engineered to absorb SWIR light at 1550nm (Eg=0.8 eV) were fabricated from solution using the Chemical Bath Deposition (CBD) technique. The layers were grown on top of two different n-type CdS intermediate layers (Eg=2.4 eV) using two different CBD protocols on Fluoride Tin Oxide (FTO) substrates. Two types of CdS/PbS heterojunction were obtained to serve as SWIR PV detectors. The two resulting devices showed similar photoluminescence behavior, but a profoundly different electrical response to SWIR illumination. One type of CdS/PbS heterojunction exhibited a PV response to SWIR light, while the other demonstrated a photo-response to SWIR light only under an applied bias. To clarify this intriguing phenomenon, and since the only difference between the two heterojunctions could be the doping level of the CdS layer, we measured the doping level of this layer by means of the surface photo voltage (SPV). This yielded different polarizations for the two devices, indicating different doping levels of the CdS for the two different fabrication protocols, which was also confirmed by Hall Effect measurements. We performed current voltage measurements under super bandgap illumination, with respect to CdS, and got an electrical response indicating a barrier free for holes transfer from the CdS to the PbS. The results indicate that the different response does, indeed, originate from variations in the band structures at the interface of the CdS/PbS heterojunction due to the different doping levels of the CdS. We found that, unlike solar cells or visible light detectors having similar structure, in SWIR photodetectors, a type I heterojunction is formed having a barrier at the interface that limits the injection of the photo-exited electrons from the QC-PbS to the CdS side. Higher n-doped CdS generates a narrow depletion region on the CdS side, with a spike like barrier that is narrow enough to enable tunneling current, leading to a PV current. Our results show that an external quantum efficiency (EQE) of ~2% and an internal quantum efficiency (IQE) of ~20% can be obtained, at zero bias, for CBD grown SWIR sensitive CdS/PbS-NDs heterojunctions.
关键词： CBD,CdS/PbS heterojunction,SWIR photodetector,PbS NDs
更新于2025-09-23 15:19:57
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Effect of Polymer Capping on Photonic Multi-Corea??Shell Quantum Dots CdSe/CdS/ZnS: Impact of Sunlight and Antibacterial Activity
摘要： The highly luminescent CdSe/CdS/ZnS core?multi-shell quantum dots (QDs) were prepared without a protective atmosphere through the precursor injection method (phosphine free) in paraffin liquid and oleic acid. Polymers (PEG, PVA, PVP, and PAA) were coated to CdSe/CdS/ZnS core?multi-shell quantum dots to increase stability. However, core?multi-shell structured QDs reveal enhanced emission in the range 355?410 nm by suppressing the defect sensitive cores and nonradioactive recombination in PL spectra. The cubic zinc blended quantum dots with crystallite size in the range 22?44 nm, as confirmed by XRD, were obtained. The resultant absorption spectra of all the samples showed that the samples were absorbent in the UV region over the 302?380 nm range. In the FT-IR spectrum 712, 731, and 400?700 cm?1 band values were assigned to CdSe, CdS, and ZnS band stretching, respectively. Images of CdSe, CdSe/CdS, and CdSe/CdS/ZnS quantum dots obtained from the SEM were spherical whereas QDs capped with different polymers (PEG, PVA, PVP, and PAA) showed nanofibers that were linear and homogeneous size ranged between 12 and 38 nm. These as prepared QDs were placed under visible light for 48 h. After absorbing UV light, the range of UV?vis intensity was enhanced until 389?464 nm and emission intensity enhanced until 492?509 nm, which was confirmed by UV and PL spectra. CdSe/CdS/ZnS QDs with organic ligands revealed antibacterial activity over a broad range against Klebsiella Pneumoniae and Pseudomonas aeruginosa.
关键词： CdSe/CdS/ZnS,Photoluminescence,Polymer capping,Quantum dots,Antibacterial activity
更新于2025-09-23 15:19:57
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[IEEE 2019 19th International Conference on Advanced Robotics (ICAR) - Belo Horizonte, Brazil (2019.12.2-2019.12.6)] 2019 19th International Conference on Advanced Robotics (ICAR) - An Auto-Focusing System for Endoscopic Laser Surgery based on a Hydraulic MEMS Varifocal Mirror
摘要： Touch-based interactivity has become an important function in displays. This paper reports on the signal processing of touch signals in which touch interactivity is processed as an image, and correlated double sampling (CDS) algorithm is applied for both common-mode noise reduction and global multivalued offset cancellation. Based on experimental results, we achieved a boost in SNR of 7.6 dB. The processed signal reduces detection errors and power consumption of the system.
关键词： Capacitance touchscreen,common-mode noise,global multivalued offset,correlated double sampling (CDS),image signal processing
更新于2025-09-23 15:19:57
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Effect of co-sensitization of InSb quantum dots on enhancing the photoconversion efficiency of CdS based quantum dot sensitized solar cells
摘要： The effect of co-sensitization of CdS and InSb Quantum Dots (QDs) on the enhancement of efficiency of Quantum Dots Sensitized Solar Cells (QDSSCs) has been investigated. InSb is synthesized by a facile solvothermal method using indium metal particles and antimony trichloride as precursors. From TEM images the average particle size of InSb was found to be less than 25 nm. The I–V data showed photoconversion efficiency (PCE) of 0.8% using InSb QDs as a sensitizer layer for QDSSC. However, co-sensitization of InSb QDs and CdS QDs on the TiO2 photoanode in QDSSCs showed an enhanced PCE of 4.94% compared to that of CdS sensitized solar cells (3.52%). The InSb QD layer broadens the light absorption range with reduced spectral overlap causing an improvement in light harvesting along with suppression of surface defects which reduced the recombination losses. As a result, co-sensitized TiO2/CdS/InSb QDSSC exhibits a greatly improved PCE of 4.94%, which is 40% higher than that of TiO2/CdS (3.52%) based QDSSCs due to improved light absorption with low recombination losses.
关键词： quantum dot sensitized solar cells,co-sensitization,photoconversion efficiency,CdS,InSb quantum dots
更新于2025-09-23 15:19:57
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Synthesis and characterization of CdS@ZnO nanoribbon@quantum dot and their enhanced visible-light-driven photocatalytic activities
摘要： CdS/ZnO nanoribbon/quantum dot was prepared using thermal decomposition method. Size and distribution of ZnO quantum dots on CdS nanobelt were controlled by concentrations of zinc acetate ethanol solution and thermal decomposition temperature. The structure and optical properties of CdS nanobelts and CdS/ZnO heterostructures are studied by XRD, TEM, PL and Raman scattering and UV–Vis absorption spectra. The photocatalytic performances of CdS nanobelts and CdS/ZnO heterostructures are tested by photocatalytic degradation of RhB aqueous solution under visible light irradiation. Compared with that (83.57%) of CdS nanobelts, the degradation rate (88.66%) of RhB using CdS/ZnO heterostructures as catalyst is significantly improved, which suggests better development prospect in photocatalytic technology and photoelectric device.
关键词： photocatalytic activities,thermal decomposition method,CdS@ZnO nanoribbon@quantum dots,optical properties
更新于2025-09-23 15:19:57
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Incorporating Selfa??assembled Silanea??crosslinked Carbon Dots into Perovskite Solar Cells to Improve Efficiency and Stability
摘要： Carbon dots (CDs) have significant potential in the chemical decoration, crystal modification, and surface passivation of perovskite photovoltaics. However, incompatibility between the hydrophilic/hygroscopic nature of CDs and moisture sensitive perovskite remains an issue. Solving this problem would yield a significant improvement for stable perovskite devices embedded with CDs. Herein, the hydrophobic passivation layers are realized for perovskite solar cells (PSCs) through the surface engineering of CDs, exploiting electrostatic self–assembly of trichloro(3,3,3–trifluoropropyl)silane (C3H4Cl3F3Si) and CDs. The embedded CDs modify perovskite grains and passivate grain boundary defects, thereby promoting the carrier lifetime and charge collection. The inserted C3H4Cl3F3Si insulating layer provides the tunneling junction at the contact of perovskite and electron transport layer. This tunneling layer can selectively conduct electrons and block the holes, which spatially separate photo–generated carriers to suppress their recombination. As a result, the optimized perovskite devices deliver the highest efficiency of 21.12% with a high fill factor of 82.86%. Moreover, the variation of surface wettability can be achieved by the self–assembly of C3H4Cl3F3Si, which improves the stability of perovskite devices by maintaining nearly 90% efficiency forover 30 days’ exposure to ambient without encapsulation.
关键词： Perovskite solar cells,Self–assembly,tunneling layer,CDs–SAM,Moisture stability
更新于2025-09-23 15:19:57