Epitaxially-fused superlattices of colloidal quantum dots (QD epi-SLs) may exhibit electronic minibands and high-mobility charge transport, but electrical measurements of epi-SLs have been limited to large-area, polycrystalline samples in which superlattice grain boundaries and intragrain defects suppress/obscure miniband effects. Systematic measurements of charge transport in individual, highly-ordered epi-SL grains would facilitate the study of minibands in QD films. Here, we demonstrate the air-free fabrication of microscale field-effect transistors (μ-FETs) with channels consisting of single PbSe QD epi-SL grains (2-7 μm channel dimensions) and analyze charge transport in these single-grain devices. The eight devices studied show -channel or ambipolar transport with a hole mobility as high as 3.5 cm V s at 290 K and 6.5 cm V s at 170-220 K, one order of magnitude larger than that of previous QD solids. The mobility peaks at 150-220 K, but device hysteresis at higher temperatures makes the true mobility-temperature curve uncertain and evidence for miniband transport inconclusive.
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http://dx.doi.org/10.1021/acs.nanolett.2c03657 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Ministry of Education, Beijing 100044, China.
Quasi-two-dimensional (quasi-2D) mixed-halide perovskites are a requisite for their applications in highly efficient blue perovskite light-emitting diodes (PeLEDs) owing to their strong quantum confinement effect and high exciton binding energy. The pace of quasi-2D blue PeLEDs is hindered primarily by two factors: challenges in precisely managing the phase distribution and defect-mediated nonradiative recombination losses. Herein, we utilize 2,2-diphenylethylamine (DPEA) with bulky steric hindrance to disturb the assembly process of a slender spacer host cation, 4-fluorophenylethylammonium (-F-PEA), enhancing phase distribution management in quasi-2D PeLEDs.
View Article and Find Full Text PDFSci Rep
January 2025
Qatar Environment & Energy Research institute (QEERI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 34110, Doha, Qatar.
Keto-enol tautomerism in organic molecules presents a potential for modulating the charge transport at the nanoscale. The reduction of the isomerization barrier and favoring the highly conductive enol form are the main challenges towards practical implementation of this phenomenon. Using density functional theory calculations, we have demonstrated that pyridinic nitrogen in biphenyl molecules with keto-enol tautomerism can successfully make the conductive enol form energetically more favorable.
View Article and Find Full Text PDFACS Nano
January 2025
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Pulsatile ion transport facilitates the adjusted transfer of substances, meeting the requirements for the gradient and timed separation of multiple components in membrane processes. Responsive nanofiltration membranes are thus currently receiving widespread attention but face limitations due to their narrow performance adjustment range. Herein, hydroxyl functional groups were introduced into electrically responsive nanofiltration membranes to broaden the adjustment range of separation performance through a combination of pore size sieving and functional group interactions, resulting in a greater change in rejection and flux compared to the original membrane.
View Article and Find Full Text PDFSci Total Environ
January 2025
Department of Geosciences & Natural Resource Management, Geology, University of Copenhagen, Denmark.
Due to increasing plastic production, the continuous release of primary and secondary nanoplastic particles (NPs, <1 μm) has become an emerging contaminant in terrestrial environments. The fate and transport of NPs in subsurface environments remain poorly understood, largely due to the complex interplay of mineralogical, chemical, biological, and morphological heterogeneity. This study examines interactions between abundant subsurface minerals and NPs under controlled water chemistry (1 mM KCl, pH 5.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
College of Physics Science and Technology, Hebei University, Baoding 071002, China.
Developing the Cd-free electron transport layer (ETL) is a crucial subject in the field of antimony selenide (SbSe) solar cells. At present, the power conversion efficiency (PCE) of the Cd-free SbSe solar cell is still substantially lower than that of CdS-based devices. It is significant to reveal the electron transfer features in SbSe/CdS heterojunction and SbSe/Cd-free ETL heterojunction for development of a Cd-free SbSe solar cell with high PCE.
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