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Optical and structural-chemistry of SnS nanocrystals prepared by thermal decomposition of bis(N-di-isopropyl-N-octyl dithiocarbamato)tin(II) complex for promising materials in solar cell applications
摘要： Mixed ligand precursor complex bis(N-di-isopropyl-N-octyl dithiocarbamato)tin(II) complex was synthesized from its respective dithiocarbamate ligands, characterized and thermalized through thermogravimetric analysis to yield tin sulfide (SnS) nanocrystals. The thermal decomposition pattern was recorded as a function of the required temperature for the formation of the SnS nanocrystals at 360 °C. The SnS nanocrystals were characterized using optical, vibrational, structural and morphological analyses instruments. The obtained orthorhombic phase SnS nanocrystals showed indirect and direct optical energy band gaps close to the 1.5 eV of the bulk SnS.
关键词： SnS nanocrystals,Thermal decomposition pattern,Mixed ligand precursor complex,Orthorhombic phase,Thermogravimetric analysis
更新于2025-09-19 17:13:59
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Cesium Lead Halide Perovskite Nanocrystals Prepared by Anion-exchange for Light-Emitting Diodes
摘要： Cesium lead halide perovskite nanocrystals (NCs) have emerged as a promising emitter for lighting and display technologies. However, the iodide containing CsPb(Br/I)3 and CsPbI3 NCs suffer from chemical and phase degradation to non-functional orthorhombic (δ) phase. To address this challenge, we developed a facile synthetic protocol for halide exchange in pristine CsPbBr3 NCs. The protocol involves change in the nucleophilicity (or basicity) of the halide ions in aqueous-organic media which acts as the driving force to facilitate the halide exchange. Our method avoids the use of additives for anion solubilization, which otherwise induces chemical instability and quench the emission. The halide exchanged CsPb(Br/I)3 and CsPbI3 NCs showed enhanced structural and optical properties, such as high phase stability and emission quantum yields up to 94.2% as compared to the NCs (of same composition) obtained from direct synthesis. In addition, we demonstrated fabrication of light emitting devices (LED) based on halide exchanged CsPb(Br/I)3 and CsPbI3 NCs. The devices showed peak external quantum efficiency (EQE) of 1.9% with a peak wavelength of 670 nm and low luminance turn-on voltage of 2.5 V.
关键词： Lead halide Perovskite,Halide exchange,Quantum dots,Nanocrystals,LED
更新于2025-09-19 17:13:59
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Sustainable Quantum Dot Chemistry: Effects of Precursor, Solvent, and Surface Chemistry on the Synthesis of Zn3P2 Nanocrystals
摘要： The quest of exploring alternative materials for the replacement of toxic cadmium- and lead-based quantum dots (QDs), is necessary for envisaging a sustainable future but remains highly challenging. Tackling this issue, we present the synthesis of Zn3P2 nanocrystals (NCs) of unprecedented quality. New, reactive zinc precursors yield highly crystalline, colloidally stable particles, exhibiting oxide-free surfaces, size tunability and outstanding optical properties relative to previous reports of zinc phosphide QDs.
关键词： Surface Chemistry,Precursor,Zn3P2 Nanocrystals,Sustainable Quantum Dot Chemistry,Solvent
更新于2025-09-19 17:13:59
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Enhanced charge extraction in carbon-based all-inorganic CsPbBr3 perovskite solar cells by dual-function interface engineering
摘要： Carbon-based all-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted growing interests due to low cost and excellent tolerances toward moisture, temperature, oxygen and ultraviolet light. However, carrier recombination of CsPbBr3 film and large energy level differences at CsPbBr3/carbon interface are still the most crucial problem for further enhancement of power conversion efficiency. In the current study, an intermediate energy level at CsPbBr3/carbon interface and CsPbBr3 film passivation are employed by coating hexane solution of CsPbBrxI3-x nanocrystals (NCs) on the perovskite layer. Through systematic study on interfacial engineering, it is found that CsPbBrxI3-x NCs with tunable energy level can remarkably reduce energy loss and hexane under passivation treatment can enlarge perovskite grain size as well as reduce trap state density. A champion power conversion efficiency of 9.45% is achieved for CsPbI3 NCs tailored all-inorganic CsPbBr3 PSC in comparison with 5.26% for NCs-free device, with the unencapsulated carbon-based CsPbBr3 PSC exhibiting remarkable long-term stability over 900 h in 80% relative humidity air atmosphere at 25 °C. This work provides an effective approach to promote charge extraction and reduce defect states density as well as enhance the performance of PSCs.
关键词： CsPbBrxI3-x nanocrystals,Interface engineering,Charge extraction,Solvent treatment,All-inorganic CsPbBr3 perovskite solar cells
更新于2025-09-19 17:13:59
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High-efficiency perovskite nanocrystal light-emitting diodes <i>via</i> decorating NiO <sub/>x</sub> on the nanocrystal surface
摘要： Nickel oxides exhibit a great potential as hole transport layers for the fabrication of efficient perovskite light-emitting diodes (LEDs) due to their high carrier mobility and good energy band matching with perovskite nanocrystals. In this work, nickel oxides were directly decorated on the CsPbBr3 nanocrystal surface through adsorption and a sequential oxidation treatment. The resulting sample shows a high photoluminescence quantum-yield of 82%. The LED using CsPbBr3 nanocrystals with nickel oxides achieves a high external quantum efficiency (EQE) of up to 16.8% with a low turn-on voltage of 2.8 V, which is much superior to that of the counterpart LED based on pristine CsPbBr3 nanocrystals (EQE = 0.7%, turn-on voltage = 5.6 V). The excellent performance of the nickel oxide decorated CsPbBr3 nanocrystal device could be attributed to the better energy level matching between the decorated nanocrystals and the transport layers of the device and more balanced charge carrier injection. Furthermore, the operational lifetime of the nickel oxide decorated CsPbBr3 nanocrystal device is 40 times longer than that of the pristine CsPbBr3 nanocrystal device.
关键词： perovskite nanocrystals,photoluminescence quantum-yield,light-emitting diodes,external quantum efficiency,nickel oxides
更新于2025-09-19 17:13:59
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Heavy-Metal-Free Flexible Hybrid Polymer-Nanocrystal Photodetectors Sensitive to 1.5-μm-wavelength
摘要： Photodetection in the short-wave infrared (SWIR) wavelength window represents one of the core technologies allowing for many applications. Most current photodetectors suffer from high cost due to the epitaxial growth requirements and the ecological issue due to the use of highly toxic heavy-metal elements. Toward an alternative SWIR photodetection strategies, in this work, high-performance heavy-metal-free flexible photodetectors sensitive to λ = 1.5 μm photons are presented based on the formation of a solution-processed hybrid composing of a conjugated diketopyrrolopyrrole-base polymer/PC70BM bulk heterojunction organic host together with inorganic guest NaYF4:15%Er3+ upconversion nanoparticles (UCNPs). Under the illumination of λ = 1.5 μm SWIR photons, optimized hybrid BHJ/UCNP photodetectors exhibit a photoresponsivity of 0.73 mA/W and 0.44 mA/W respectively for devices built on rigid ITO/glass and flexible ITO/polyethylene terephthalate (PET) substrates. These hybrid photodetectors are capable of performing SWIR photodetection with a fast operation speed, characterized by a short photocurrent rise time down to 80 μs, together with an excellent mechanical robustness for flexible applications. Exhibiting simultaneously multiple advantages including solution-processability, flexibility, and the absence of toxic heavy metal elements together with a fast operation speed and good photoresponsivity, these hybrid BHJ(DPPTT-T/PC70BM)/UCNP photodetectors are promising candidates for next-generation low-cost and high-performance SWIR photodetectors.
关键词： nanocrystals,short-wave infrared,flexible,solution process,hybrid photodetectors
更新于2025-09-19 17:13:59
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Raman study of laser-induced formation of IIa??VI nanocrystals in zinc-doped Asa??S(Se) films
摘要： Zn-doped As2Se3 and As2S3 films were prepared by thermal evaporation. Their amorphous structure was confirmed by Raman spectroscopy. Zinc chalcogenide nanocrystals can be formed in the films under laser irradiation due to the photoenhanced diffusion of atoms in the arsenic chalcogenide films, which enables aggregation of Zn and S(Se) atoms in nanocrystals. For As2S3:Zn films, not only ZnS, but also ZnO crystallites can be formed under irradiation with UV laser light due to oxidation of the film surface with abundant zinc atoms.
关键词： Raman scattering,Amorphous films,II–VI nanocrystals,Arsenic chalcogenides
更新于2025-09-19 17:13:59
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Spectral Tuning of Efficient CsPbBrxCl3-x Blue Light-Emitting Diodes via Halogen Exchange Triggered by Benzenesulfonates
摘要： CsPbX3 nanocrystals (NCs)-based blue perovskite light-emitting diodes (PeLEDs) are still in a backward position while the green and red counterparts have achieved significant progress in the past few years. The emission spectrum of perovskite NCs can be manipulated via the ratio control of halides in precursor or halogen exchange of NCs. Herein, CsPbBrxCl3-x NCs are synthesized in ambient condition. With tetrabutylammonium p-toluenesulfonate (TBSA) added as the ligand during the purification process of as-synthesized perovskite NCs, bromine in NCs is substituted by chlorine and the spectrum undergoes a blue-shift, whereas chlorine is exchanged by bromine in NCs and the spectrum undergoes a red-shift by introducing sodium dodecylbenzenesulfonate (SDSA) as the ligand. The origin for halogen exchange can be attributed to the synergistic effects of anion and cation of benzenesulfonates. The photoluminescence quantum yield (PLQY) of NCs increases from 7% to 81% due to the effective passivating effects of the strong ionic sulfonate heads, and the blue PeLEDs prepared by this method show a promising external quantum efficiency (EQE) of 2.6%. Our work provides a new approach into spectral tuning of efficient blue PeLEDs.
关键词： halogen exchange,spectral tuning,blue perovskite light-emitting diodes,benzenesulfonates,CsPbX3 nanocrystals
更新于2025-09-19 17:13:59
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Controlled Growth of CH <sub/>3</sub> NH <sub/>3</sub> PbBr <sub/>3</sub> Perovskite Nanocrystals via a Water–Oil Interfacial Synthesis Method
摘要： Fundamental insights into the reaction kinetics of organic–inorganic lead halide perovskite nanocrystals (LHP NCs) are still limited due to their ultrafast formation rate. Herein, we develop a water–oil interfacial synthesis of MAPbBr3 NCs (MA = CH3NH3+), which prolongs the reaction time to tens of minutes. This method makes it possible to monitor in situ the formation process of MAPbBr3 NCs and observe successive spectral evolutions from 438 to 534 nm in a single reaction by extending reaction time. The implementation of this method depends on reducing the formation rate of PbBr64? octahedra and the diffusion rate of MA. The formation of PbBr64? is a rate-determining step, and the biphasic system offers a favorable reaction condition to control the mass transfer of MA. The effects of temperature and concentration of precursor and ligand are investigated in detail.
关键词： CH3NH3PbBr3,perovskite nanocrystals,interfacial synthesis,kinetic study,formation mechanisms
更新于2025-09-19 17:13:59
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Tailored Photoluminescence Properties of Ag(In,Ga)Se <sub/>2</sub> Quantum Dots for Near-Infrared in vivo Imaging
摘要： Multinary semiconductor quantum dots (QDs) that have less toxicity and show near-infrared light responsivity have attracted much attention for in vivo bioimaging. In this study, we controlled the optical properties of Ag-In-Se QDs by modulating the non-stoichiometry and the degree of Ga3+ doping. Precise tuning of the Ag/In ratio of Ag-In-Se QDs enabled a sharp band-edge emission to emerge without broad defect-site emission. Ga3+ doping into Ag-In-Se (AIGSe) QDs enlarged their energy gap, resulting in a blue shift of band-edge PL peak from from 890 to 630 nm. The band-edge PL intensity was remarkably enlarged by surface coating with a thin GaSx shell followed by treatment with trioctylphosphine, the highest PL yield being 38% for the PL peak at 800 nm. Thus-obtained QDs were successfully used as near-IR PL probes for three-dimensional in vivo bio-imaging in which the wavelengths of excitation and detection lights could be selected in the first biological window and then the signals were clearly detected from AIGSe@GaSx core-shell QDs injected into biological tissues by ca. 5 mm in depth.
关键词： I-III-VI2 semiconductor,Quantum dots,Semiconductor nanocrystals,Band-edge emission,Biological imaging,Near-IR photoluminescence
更新于2025-09-19 17:13:59