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Composition and size controlled I-V-VI semiconductor nanocrystals
摘要： Non-isovalent ternary and quaternary semiconductors (i.e., having two or more cations with different valence) have unique structural and electronic properties that are leveraged in photovoltaic, thermoelectric, and phase-change memory devices. Making these complex semiconductors in the form of colloidal nanocrystals imparts size-dependent properties and solution processability. Here, we present results on I‐V‐VI group colloidal nanocrystals. We focus on achieving sub-10 nm sizes for a wide range of I-V-VI selenide nanocrystals, including AgSbSe2, AgSb2Se3, CuSbSe2, Cu3SbSe4, AgBiSe2, and CuBiSe2. To highlight one possible application for these I-V-VI colloidal nanomaterials, we analyze the optical absorption and show that through composition and size control, this class of materials offers bandgaps in the mid- to near-IR. Absorption coefficients of AgSbSe2, CuSbSe2, and Cu3SbSe4 nanocrystals are on par with or higher than the well-studied PbS nanocrystals highlighting their potential for devices such as solar cells, (mid-)infrared photodetectors, and near-infrared bio-imaging systems.
关键词： solar cells,optical absorption,bio-imaging systems,colloidal nanocrystals,infrared photodetectors,mid- to near-IR,I-V-VI semiconductor nanocrystals,bandgaps
更新于2025-09-23 15:19:57
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Electrochemically-stable ligands bridge the photoluminescence-electroluminescence gap of quantum dots
摘要： Colloidal quantum dots are promising emitters for quantum-dot-based light-emitting-diodes. Though quantum dots have been synthesized with ef?cient, stable, and high colour-purity photoluminescence, inheriting their superior luminescent properties in light-emitting-diodes remains challenging. This is commonly attributed to unbalanced charge injection and/or interfacial exciton quenching in the devices. Here, a general but previously overlooked degradation channel i.e., operando electrochemical reactions of surface ligands with injected charge carriers, is identi?ed. We develop a strategy of applying electrochemically-inert ligands to quantum dots with excellent luminescent properties to bridge their photoluminescence-electroluminescence gap. This material-design principle is general for boosting electroluminescence ef?ciency and lifetime of the light-emitting-diodes, resulting in record-long operational lifetimes for both red-emitting light-emitting-diodes (T95 > 3800 h at 1000 cd m?2) and blue-emitting light-emitting-diodes (T50 > 10,000 h at 100 cd m?2). Our study provides a critical guideline for the quantum dots to be used in optoelectronic and electronic devices.
关键词： electroluminescence,light-emitting-diodes,photoluminescence,Colloidal quantum dots,electrochemical stability
更新于2025-09-23 15:19:57
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Effect of colloid aggregation characteristic on ZnO interface layer and photovoltaic performance of polymer solar cells
摘要： ZnO as a classical n-type semiconductor oxide is widely used as the electron transport layer for high-efficiency polymer solar cells by using solution processing. To study the effect of ZnO colloid aggregation size on the morphology of ZnO interface layer and photovoltaic performance of polymer solar cells. The ZnO colloid aggregation size was adjusted by aging time, and the PTB7-Th:PC71BM solar cells with various ZnO interface layers were fabricated. The results showed that morphology, structure and property of ZnO interface layer were depended on the ZnO colloid particle size, and then determined the photoelectric performance of the PTB7-Th:PC71BM solar cell. The best performance of PTB7-Th:PC71BM solar cell with 10.21% was obtained when the ZnO precursor solution was set at 2 h aging. The ZnO interface layer with good morphology and appropriate energy level improved the mobility and lifetime of charge carrier. Moreover, it also attributed good interface contact between the ZnO layer and the PTB7-Th:PC71BM active layer, which enhanced the electron transfer and reduced the charge recombination at the interface.
关键词： ZnO colloidal particle size,ZnO interface layer,Polymer solar cells,Aging time,Photovoltaic performance
更新于2025-09-23 15:19:57
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Scalable Synthesis of InAs Quantum Dots Mediated through Indium Redox Chemistry
摘要： Next-generation optoelectronic applications centered in the near-infrared (NIR) and short-wave infrared (SWIR) wavelength regimes require high-quality materials. Among these materials, colloidal InAs quantum dots (QDs) stand out as an infrared-active candidate material for biological imaging, lighting, and sensing applications. Despite significant development of their optical properties, the synthesis of InAs QDs still routinely relies on hazardous, commercially unavailable precursors. Herein, we describe a straightforward single hot injection procedure revolving around In(I)Cl as the key precursor. Acting as a simultaneous reducing agent and In source, In(I)Cl smoothly reacts with a tris(amino)arsenic precursor to yield colloidal InAs quantitatively and at gram scale. Tuning the reaction temperature produces InAs cores with a first excitonic absorption feature in the range of 700?1400 nm. A dynamic disproportionation equilibrium between In(I), In metal, and In(III) opens up additional flexibility in precursor selection. CdSe shell growth on the produced cores enhances their optical properties, furnishing particles with center emission wavelengths between 1000 and 1500 nm and narrow photoluminescence full-width at half-maximum (FWHM) of about 120 meV throughout. The simplicity, scalability, and tunability of the disclosed precursor platform are anticipated to inspire further research on In-based colloidal QDs.
关键词： colloidal synthesis,InAs quantum dots,short-wave infrared,optoelectronic applications,near-infrared
更新于2025-09-23 15:19:57
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Thermo-responsive plasmonic systems: old materials with new applications
摘要： Thermo-responsive plasmonic systems of gold and poly(N-isopropylacrylamide) have been actively studied for several decades but this system keeps reinventing itself, with new concepts and applications which seed new fields. In this minireview, we show the latest few years development and applications of this intriguing system. We start from the basic working principles of this puzzling system which shows different plasmon shifts for even slightly different chemistries. We then present its applications to colloidal actuation, plasmon/meta-film tuning, and bioimaging and sensing. Finally we briefly summarize and propose several promising applications of the ongoing effort in this field.
关键词： plasmon/meta-film tuning,colloidal actuation,poly(N-isopropylacrylamide),bioimaging,gold,sensing,Thermo-responsive plasmonic systems
更新于2025-09-23 15:19:57
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A Chemically Orthogonal Hole Transport Layer for Efficient Colloidal Quantum Dot Solar Cells
摘要： Colloidal quantum dots (CQDs) are of interest in light of their solution-processing and bandgap tuning. Advances in the performance of CQD optoelectronic devices require fine control over the properties of each layer in the device materials stack. This is particularly challenging in the present best CQD solar cells, since these employ a p-type hole-transport layer (HTL) implemented using 1,2-ethanedithiol (EDT) ligand exchange on top of the CQD active layer. It is established that the high reactivity of EDT causes a severe chemical modification to the active layer that deteriorates charge extraction. By combining elemental mapping with the spatial charge collection efficiency in CQD solar cells, the key materials interface dominating the subpar performance of prior CQD PV devices is demonstrated. This motivates to develop a chemically orthogonal HTL that consists of malonic-acid-crosslinked CQDs. The new crosslinking strategy preserves the surface chemistry of the active layer beneath, and at the same time provides the needed efficient charge extraction. The new HTL enables a 1.4× increase in charge carrier diffusion length in the active layer; and as a result leads to an improvement in power conversion efficiency to 13.0% compared to EDT standard cells (12.2%).
关键词： hole transport layers,colloidal quantum dots,solar cells,chemical orthogonality,surface ligands
更新于2025-09-23 15:19:57
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Narrowband colloidal quantum dot photodetectors for wavelength measurement applications
摘要： High performance photodetectors based on colloidal quantum dots have been demonstrated in a wide spectral range spanning from the visible to the mid infrared. Quantum dot photodetectors typically show a low-pass type spectral response with a tunable cutoff wavelength. In this paper, we propose a method for the realization of narrowband photodetectors based on the combination of photoconductors and optical filters, both realized with colloidal PbS quantum dots. We demonstrate that an array of such narrowband photodetectors can be effectively employed for the realization of a compact wavemeter operating in the visible and near-infrared spectral range.
关键词： Narrowband photodetectors,Wavelength meter,Colloidal Quantum Dots photodetectors
更新于2025-09-23 15:19:57
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Under-Etched Plasmonic Disks on Indium Tin Oxide for Enhanced Refractive Index Sensing on a Combined Electrochemical and Optical Platform
摘要： A simple approach to enhance the refractive index sensitivity of gold nanodisks immobilized on electrically conducting indium tin oxide (ITO) substrates has been demonstrated. A two-fold increase in sensitivity to bulk refractive index change was achieved by substrate under-etching of gold nanodisks on ITO in 50 mM sulfuric acid. The influence of an intermediate titanium adhesion layer was investigated and was found to markedly influence the etching pattern and time. Etching with an adhesion layer resulted in enhanced refractive index sensitivity on disk-on-pin like structures after long etching times, whereas etching of disks deposited directly on ITO resulted in a disk-on-pincushion like configuration and similarly enhanced sensitivity already at shorter times. The gold disks remained electrically connected to the ITO substrate throughout etching and allowed site-specific electrodeposition of poly(3-aminophenol) at the nanodisks, showing enhanced thin-film refractive index sensitivity. This work demonstrates a simple method for enhancing refractive index sensitivity of nanostructures on ITO substrates for combined electrochemical and optical platforms, and subsequently a method to modify the surface of the electrically connected nanostructures, which has potential application in biosensing.
关键词： plasmonics,refractive index sensor,colloidal lithography
更新于2025-09-23 15:19:57
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Dextran-Functionalized Semiconductor Quantum Dot Bioconjugates for Bioanalysis and Imaging
摘要： The prerequisites for maximizing the advantageous optical properties of colloidal semiconductor quantum dots (QDs) in biological applications are effective surface functionalization and bioconjugation strategies. Functionalization with dextran has been highly successful with some nanoparticle materials, but has had very limited application with QDs. Here, we report the preparation, characterization, and proof-of-concept applications of dextran-functionalized QDs. Multiple approaches to dextran ligands were evaluated, including performance with respect to colloidal stability across a range of pH, nonspecific binding with proteins and cells, and microinjection into cells and viability assays. Multiple bioconjugation strategies were demonstrated and applied, including covalent coupling to develop a simple pH sensor, binding of polyhistidine-tagged peptides to the QD for energy transfer-based proteolytic activity assays, and binding with tetrameric antibody complexes (TACs) to enable a sandwich immunoassay and cell immunolabeling and imaging. Our results show that dextran ligands are highly promising for the functionalization of QDs, and that the design of the ligands is tailorable to help optimally meet the requirements of applications.
关键词： dextran,quantum dots,colloidal stability,imaging,bioconjugation,bioanalysis
更新于2025-09-23 15:19:57
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Ligand engineering of colloid quantum dots and their application in all-inorganic tandem solar cells
摘要： How to effectively utilize the energy of the broad spectrum of sunlight is one of the basic problems in the research of tandem solar cells. Due to their size effect, quantum confinement effect and coupling effect, colloidal quantum dots (QDs) exhibit new physical properties that bulk materials don’t possess. CdX (X=Se, S, etc.) and PbX (X=Se, S, etc.) QDs prepared by hot-injection methods have been widely studied in the areas of photovolitaic devices. However, the surfactants surrounding QDs seriously hinder the charge transport of QDs based solar cells. Therefore, how to fabricate high-performance tandem solar cells via ligands engineering has become a major challenge. In this paper, the latest progress of colloidal QDs in the research of all-inorganic tandem solar cells was summarized. Firstly, the improvement of QDs surface ligands and the optimization of ligands engineering were discussed, and the control of the physical properties of QDs films were realized. From the aspects of colloidal QDs, ligand engineering, and solar cell preparation, the future development direction of colloidal QDs solar cells was proposed, providing technical guidances for the preparation of low-cost and high-efficiency nanocrystalline solar cells.
关键词： Tandem solar cell,Colloidal quantum dots,Hot-injection method,Ligand engineering
更新于2025-09-23 15:19:57