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Improving the photovoltaic performance of CdSe0.2S0.8 alloyed quantum dot sensitized solar cells using CdMnSe outer quantum dot
摘要： In this paper, by introducing the Mn-doped CdSe (CdMnSe) layer as outer quantum dot (QD) on ternary CdSe0.2S0.8 QDs surface, we developed an effective way to enhance the power conversion efficiency (PCE) of the CdSexS1-x alloyed quantum dot sensitized solar cells (QDSSCs) when the molar ratio of Se/Na2S·9H2O is 1:4. As a result, a cascade band structure and the midgap states which favorable for electron injection and the hole transport, are obtained when the concentration of Cd2+, Se2+ and Mn2+ ions are 0.5, 0.5 and 0.05 M, respectively, in the CdMnSe outer QD deposited by the successive ionic layer absorption and reaction (SILAR) method with three cycles. Hence, with using polysulfide electrolyte and Cu2S-brass as counter electrode, the measured PCE for the CdSe0.2S0.8/10%CdMnSe QDSSC is 5.420% (Voc = 0.70 V, Jsc = 16.834 mA.cm?2, and FF = 0.460) at AM 1.5G, which is higher than the PCE of 4.327% for the device with bare CdSe0.2S0.8 QDs or a ~25.5% increase. Our findings indicate that such improvement in PCE is caused by the increasing of light-absorption, decrease of the surface roughness, improvement of electrons transfer from QDs to TiO2 CB, reduction of electrons recombination and thereby, the increasing collection of electrons in TiO2 film.
关键词： CdMnSe outer QD,Ternary CdSe0.2S0.8 QDs,Quantum dot sensitized solar cells,Cascade band structure
更新于2025-09-19 17:13:59
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Facile synthesis and color conversion of Cu-doped ZnSe quantum dots in an aqueous solution
摘要： A facile growth-doping method in aqueous solution has been developed to synthesize Cu-doped ZnSe (ZnSe:Cu) QDs by using thioglycolic acid (TGA) as a stabilizer. The effects of the Cu doping concentration, reaction temperature and pH value on the synthesis of ZnSe:Cu QDs were investigated systematically. The as-synthesized ZnSe:Cu QDs with an excellent green emission still belong to a cubic zinc blende crystalline structure, and the average particle size is approximately 3.0 nm. The photoluminescent quantum yield (PLQY) is as high as 20%, and the exciton radiative lifetime is approximately 113.8 ns. Moreover, the patterned ZnSe:Cu QDs thin films have been successfully fabricated by using an inkjet printing method to verify the ability of the potential application to the color conversion. With the assistance of 5.5 pair distributed bragg reflector (DBR) structures, the color coordinate of the ZnSe:Cu QDs thin film excited by the blue LEDs is located at (0.2182, 0.4352) and the intensity of PL peak located at 513 nm reaches to be 45.1%. In addition, the PLQY of color conversion-based ZnSe:Cu QDs thin film is approximately 9.64%. Based on these results, ZnSe:Cu QDs are potentially useful for the fabrication of optoelectronic devices, especially QDs photoluminescence and electroluminescence.
关键词： color conversion,Cu-doped ZnSe QDs,photoluminescent quantum yield,inkjet printing,aqueous solution
更新于2025-09-16 10:30:52
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p-GaN/n-ZnO Nanoplate/CsPbBr3 Quantum Dots Heterojunction Light-Emitting Diode for Dual-Wavelength Emission
摘要： In this paper, we report a p-GaN/n-ZnO nanoplate/CsPbBr3 quantum dots (QDs) heterojunction light-emitting diode (LED) for dual-wavelength emission. ZnO nanoplates were prepared by vapor phase transport on the GaN thin film to form the p-GaN/n-ZnO nanoplate heterojunction. Afterwards, green CsPbBr3 QDs (band gap of 2.25 eV) were deposited on ZnO nanoplates to realize green light emission. The structure and photoluminescence of the ZnO nanoplates and CsPbBr3 QDs were characterized. The as-prepared LED device with turn-on voltage of ~ 2.7 V displays a typical rectification behavior. The electroluminescence spectra with narrow emission peaks reveal the device presents commendable dual-wavelength electroluminescence performance at ~ 385 nm and ~ 512 nm and the electroluminescence intensity saturates at about 65 mA/cm2. Moreover, the detailed electroluminescence mechanism including emission originate of n-ZnO/p-GaN heterojunction was discussed based on the band diagram. Thus, our work indicates compelling potential for the practical application of perovskite LEDs.
关键词： CsPbBr3 QDs,Light emitting diode,electroluminescence,ZnO nanoplate
更新于2025-09-16 10:30:52
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Effect of surface ligands with different terminal group on the optical stability and cytotoxicity of CuInS <sub/>2</sub> /ZnS quantum dots with the crystal structure of sphalerite
摘要： A novel method for preparing CuInS2/ZnS quantum dots (CuInS2/ZnS QDs) with the crystal structure of sphalerite by one-pot hot injection was developed in this paper. The as-prepared core CuInS2 quantum dots (CuInS2 QDs) was uniform spherical nanoparticle with the average diameter of about 2 nm with the ?uorescent quantum yields (QY) of about 2.6%. By capping a shell of ZnS on the surface of CuInS2 QDs, the formed CuInS2/ZnS QDs exhibited obvious enhanced ?uorescent emission with the QY of about 20%. Intriguingly, the crystal structure of obtained CuInS2/ZnS QDs is sphalerite, which was con?rmed by XRD. Considering the different terminal group between these small organic molecules, mercaptoacetic acid (TGA), thioglycerol (TGC) and mercaptoethylamine (MEA) were further selected as capping molecules to exchange the surface ligands of CuInS2/ZnS QDs. The obtained CuInS2/ZnS QDs modi?ed with TGC exhibited excellent photostability in physiological conditions. To investigate the effect of ligand molecules on the biocompatible of CuInS2/ZnS QDs, the experiment on the cytotoxicity of CuInS2/ZnS QDs to A549 cells were conducted. The results indicated that CuInS2/ZnS QDs capped with TGC showed the lowest cytotoxicity while CuInS2/ZnS QDs capped with MEA exhibited the highest cytotoxicity among the three types of CuInS2/ZnS QDs modi?ed with ligands with different terminal group. These results provided a sight on how to select surface ligands to modify CuInS2/ZnS QDs when CuInS2/ZnS QDs will apply in biological ?elds.
关键词： sphalerite,photostability,CuInS2/ZnS QDs,cytotoxicity,surface ligands
更新于2025-09-16 10:30:52
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Transcriptome Profile Alteration with Cadmium Selenide/Zinc Sulfide Quantum Dots in Saccharomyces cerevisiae
摘要： Quantum Dots (QDs) are becoming more prevalent in products used in our daily lives, such as TVs and laptops, due to their unique and tunable optical properties. The possibility of using QDs as fluorescent probes in applications, such as medical imaging, has been a topic of interest for some time, but their potential toxicity and long-term effects on the environment are not well understood. In the present study, we investigated the effects of yellow CdSe/ZnS-QDs on Saccharomyces cerevisiae. We utilized growth assays, RNA-seq, reactive oxygen species (ROS) detection assays, and cell wall stability experiments to investigate the potential toxic effects of CdSe/ZnS-QDs. We found CdSe/ZnS-QDs had no negative effects on cell viability; however, cell wall-compromised cells showed more sensitivity in the presence of 10 μg/mL CdSe/ZnS-QDs compared to non-treated cells. In CdSe/ZnS-treated and non-treated cells, no significant change in superoxide was detected, but according to our transcriptomic analysis, thousands of genes in CdSe/ZnS-treated cells became differentially expressed. Four significantly differentiated genes found, including FAF1, SDA1, DAN1, and TIR1, were validated by consistent results with RT-qPCR assays. Our transcriptome analysis led us to conclude that exposure of CdSe/ZnS-QDs on yeast significantly affected genes implicated in multiple cellular processes.
关键词： yeast,QDs,gene expression,toxicity,CdSe/ZnS,RNA-seq
更新于2025-09-16 10:30:52
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Label-free quantum dot conjugates for human protein IL-2 based on molecularly imprinted polymers
摘要： Herein, the development of a fluorescent-based sensor by combining quantum dots (QDs) with molecularly-imprinted technology (MIP), intensively optimized to generate exceptional operating features is presented. This sensor is designed to target human interleukin-2 (IL-2) in synthetic human serum. IL-2 is a regulatory protein released as a triggered response from the immune system towards an inflammation. For this purpose, cadmium telluride (CdTe) QDs are prepared with 3-mercaptopropionic acid (MPA) and modified afterwards to produce an IL-2 imprinted polymer with methacrylic acid and N,N′-methylenebis(acrylamide), upon removal of the template under optimized conditions. During IL-2 rebinding, the fluorescence intensity of CdTe@MPA QDs is quenched in a concentration dependent manner. Using surface imprinting technology, the optimal fluorescence signals yielded a linear response versus logarithm of IL-2 concentration from 35 fg/ml to 39 pg/ml, in a 1000-fold diluted synthetic human serum. The limit of detection obtained is 5.91 fg/ml, lying below the concentration levels of IL-2 with clinical interest for cancer diagnosis (9.4-19.2 pg/ml). Overall, the method presented herein is a demonstration that the combination of MIP and QDs for protein detection constitutes a powerful tool in clinical analysis, providing low cost, sensitive and quick responses. The same concept may be further extended to other proteins of interest.
关键词： interleukin-2,conjugated-QDs,protein,molecularly imprinted polymer,Quantum dots,cancer biomarker
更新于2025-09-16 10:30:52
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Low-cost uncooled MWIR PbSe quantum dots photodiodes
摘要： A mid-wave infrared (MWIR) uncooled PbSe-QDs/CdS p–n heterojunction photodiode has been fabricated using a wet-chemical synthesis route. This offers a low-cost alternative to traditional monocrystalline photodiodes relying on molecular beam epitaxy (MBE) technology. It was demonstrated that the post-annealing is critical to tailor the photoresponse wavelength and to improve the performance of photodiodes. After annealing at 673 K in air for 0.5 h, the ligand-free PbSe-QDs/CdS photodiode exhibits a MWIR spectral photoresponse with a cutoff wavelength of 4.2 mm at room temperature. Under zero-bias photovoltaic mode, the peak responsivity and specific detectivity at room temperature are 0.36 (cid:1) 0.04 A W(cid:3)1 and (8.5 (cid:1) 1) (cid:4)108 cm Hz1/2 W(cid:3)1, respectively. Temperature-dependent spectral response shows an abnormal intensity variation at temperatures lower than 200 K. This phenomenon is attributed to the band alignment transition from type II to type I, resulting from the positive temperature coefficient of PbSe. In addition, it was proved that In doped CdSe (CdSe:In) films could be used as a promising new candidate of infrared transparent conductive electrodes, paving the way for monolithic integration of uncooled low-cost MWIR photodiodes on Si readout circuitry.
关键词： infrared transparent conductive electrodes,MWIR,photodiode,CdSe:In,wet-chemical synthesis,PbSe-QDs,annealing
更新于2025-09-16 10:30:52
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Water-soluble ZnO quantum dots modified by (3-aminopropyl)triethoxysilane: The promising fluorescent probe for the selective detection of Cu2+ ion in drinking water
摘要： Copper, as an essential element in human body, can have adverse impact on environment and healthy individuals if it is excessive. So it is necessary to establish a rapid and effective method for detecting Cu2+. In this work, we describe a method for determination of Cu2+ based on water-soluble ZnO quantum dots (QDs) modified with (3-aminopropyl)triethoxysilane (APTEs). The ZnO QDs functionalized with APTEs (NH2-ZnO QDs) synthesized by a simple sol-gel method and displayed strong yellow-green fluorescence with a peak at 535 nm under 350 nm excitation. High-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, luminescence, and UV-visible absorption spectroscopy were used to characterize the NH2-ZnO QDs. In addition, the emission from NH2-ZnO QDs was selectively quenched upon addition of Cu2+. Therefore, this finding was used to design a fluorescent probe based on NH2-ZnO QDs to detect Cu2+ in water solution, and the linear relationships were 2-20 nM and 1-100 μM respectively, with detection limit for Cu2+ at 1.72 nM (on the basis of 3σ/slope criterion). This fluorescent probe had also been applied in real water sample to testify its availability in drinking water. Furthermore, the quenching mechanism was studied by measurements of UV-visible absorption spectra and fluorescent lifetime of ZnO QDs, which may be attributed to the aggregation induced by Cu2+ and the dynamic quenching existing energy transfer between QDs and Cu2+.
关键词： Drinking water,Water-soluble,Fluorescent probe,Cu2+ detection,ZnO QDs,Quenching mechanism
更新于2025-09-16 10:30:52
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In Vivo Fluorescence Visualization of Anterior Chamber Injected Human Corneal Endothelial Cells Labeled With Quantum Dots
摘要： The injection of cultured human corneal endothelial cells (cHCECs) into the anterior chamber (AC) is a newly developed modality for the successful treatment of corneal endothelium dysfunction. Here, we investigated whether or not cHCECs could be labeled using quantum dots (QDs) composed of semiconductor nanoparticle octa-arginine (R8) to trace injected cHCECs and examined the utility of in vivo fluorescence imaging to analyze the dynamics and accumulation of QD-labeled injected cHCECs in a corneal endothelial dysfunction mouse model.
关键词： cultured human corneal endothelial cells (cHCECs),in vivo fluorescence imaging,quantum dots (QDs)
更新于2025-09-16 10:30:52
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Tuning the photoinduced charge transfer from CdTe quantum dots to ZnO nanofilms through Ga doping
摘要： Tuning the charge transfer rate between quantum dots (QDs) and metal oxide (MO) is important for improving the performances of QDs-MO devices. And tailoring the energy band of MO is one way to tune the charge transfer rate. In this work, we enhance the charge transfer rate between CdTe QDs and ZnO through tailoring the optical band gap of ZnO nano?lms by Ga-doping. The Ga doping in?uenced the photo luminescence (PL) performance of CdTe QDs/ZnO hybrid structures. The results of time-resolved ?uorescence spectra revealed that the charge transfer rate from CdTe QDs to ZnO nano?lms could be tuned by varying the Ga doping concentrations in ZnO. And, transfer rate were increased by up to ~4.1 times through Ga doping. In addition, the structure showed electron transfer e?ciency improvements to the tune of ~25.3%. We attribute the improvement to e?cient electron transfer via band-band transfer and the defects pathways induced by Ga-doping. The experimental results will be useful for improving the e?ciency of optical devices using QDs/ZnO hybrid structure.
关键词： Doping,Semiconductors,Electron transfer,Time-resolve ?uorescence spectra,QDs/ZnO hybrid structures
更新于2025-09-16 10:30:52