scholarly journals Spin-dependent charge transport through 2D chiral hybrid lead-iodide perovskites

2019 ◽  
Vol 5 (12) ◽  
pp. eaay0571 ◽  
Author(s):  
Haipeng Lu ◽  
Jingying Wang ◽  
Chuanxiao Xiao ◽  
Xin Pan ◽  
Xihan Chen ◽  
...  
Keyword(s):  
Charge Transport ◽  
Organic Molecules ◽  
Spin Valve ◽  
Lead Iodide ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hybrid Perovskite ◽  
The Media ◽  
Inorganic Framework ◽  
Inorganic Layers

Chiral-induced spin selectivity (CISS) occurs when the chirality of the transporting medium selects one of the two spin ½ states to transport through the media while blocking the other. Monolayers of chiral organic molecules demonstrate CISS but are limited in their efficiency and utility by the requirement of a monolayer to preserve the spin selectivity. We demonstrate CISS in a system that integrates an inorganic framework with a chiral organic sublattice inducing chirality to the hybrid system. Using magnetic conductive-probe atomic force microscopy, we find that oriented chiral 2D-layered Pb-iodide organic/inorganic hybrid perovskite systems exhibit CISS. Electron transport through the perovskite films depends on the magnetization of the probe tip and the handedness of the chiral molecule. The films achieve a highest spin-polarization transport of up to 86%. Magnetoresistance studies in modified spin-valve devices having only one ferromagnet electrode confirm the occurrence of spin-dependent charge transport through the organic/inorganic layers.

scholarly journals Degradation Mechanism of Porous Metal-Organic Frameworks by In Situ Atomic Force Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 722
Author(s):  
Ioanna Christodoulou ◽  
Tom Bourguignon ◽  
Xue Li ◽  
Gilles Patriarche ◽  
Christian Serre ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Degradation Mechanism ◽  
Metal Organic Frameworks ◽  
Porous Metal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Organic ◽  
The Media ◽  
Ph Conditions

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs’ stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

scholarly journals Mobility of charge carriers in self-assembled monolayers

2019 ◽  
Vol 10 ◽  
pp. 2449-2458
Author(s):  
Zhihua Fu ◽  
Tatjana Ladnorg ◽  
Hartmut Gliemann ◽  
Alexander Welle ◽  
Asif Bashir ◽  
...  
Keyword(s):  
Charge Transport ◽  
Charge Carrier Mobility ◽  
Charge Carriers ◽  
Self Assembled Monolayers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mobility Of Charge Carriers ◽  
Assembled Monolayers ◽  
Self Assembled

We present a new approach to study charge transport within 2D layers of organic semi-conductors (OSCs) using atomic force microscopy (AFM)-based lithography applied to self-assembled monolayers (SAMs), fabricated from appropriate organothiols. The extent of lateral charge transport was investigated by insulating pre-defined patches within OSC-based SAMs with regions of insulating SAM made from large band gap alkanethiolates. The new method is demonstrated using a phenyl-linked anthracenethiolate (PAT), 4-(anthracene-2-ylethynyl)benzyl thiolate. I–V characteristics of differently shaped PAT-islands were measured using the AFM tip as a top electrode. We were able to determine a relationship between island size and electrical conductivity, and from this dependence, we could obtain information on the lateral charge transport and charge carrier mobility within the thin OSC layers. Our study demonstrates that AFM nanografting of appropriately functionalized OSC molecules provides a suitable method to determine intrinsic mobilities of charge carriers in OSC thin films. In particular, this method is rather insensitive with regard to influence of grain boundaries and other defects, which hamper the application of conventional methods for the determination of mobilities in macroscopic samples.

Towards a Room Temperature Organic Spin Valve: Structural, Magnetic and Transport Properties of Fe3O4/PTCTE/Co Devices

2011 ◽  
Vol 1359 ◽  
Author(s):  
Mathieu Palosse ◽  
Elena Bedel-Pereira ◽  
François Olivié ◽  
Isabelle Séguy ◽  
Christina Villeneuve ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Current Distribution ◽  
Morphological Study ◽  
Room Temperature ◽  
Spin Valve ◽  
Vibrating Sample Magnetometer ◽  
Force Microscopy ◽  
Dc Sputtering ◽  
Ferromagnetic Electrodes ◽  
Atomic Force

ABSTRACTThis paper describes first steps in preparation of an organic spin valve based on a perylene derivative (PTCTE) sandwiched between magnetite (Fe3O4) and cobalt (Co) ferromagnetic electrodes. MgO(001)/Fe3O4/PTCTE (450 nm)/Co devices were prepared with different Co soft deposition methods: off-axis dc-sputtering or Joule evaporation. Vibrating Sample Magnetometer (VSM) studies of the Fe3O4/PTCTE/Co stacks evidence spin valve behavior with magnetically uncoupled electrodes. These results are correlated with a morphological study by atomic force microscopy (AFM) of each layer and tunneling AFM (TUNA) for the investigation of inhomogeneity of current distribution in the devices. Finally, macroscopic I-V characteristics performed on the same devices will be presented and compared with TUNA results.

Structural and Optical Properties of PbI2 Thin Films to Fabricate Perovskite Solar Cells

2020 ◽  
Vol 398 ◽  
pp. 140-146
Author(s):  
Kawther A. Khalaph ◽  
Zainab J. Shanan ◽  
Aqel Mashot Jafar ◽  
Falah Mustafa Al-Attar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Energy Gap ◽  
Perovskite Solar Cells ◽  
Lead Iodide ◽  
Structural And Optical Properties ◽  
Solar Cell Application ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force

Recently, lead iodide is the most materials employment in the perovskite solar cell application. This paper has studied the character of preparation, structural and optical properties of pbI2 materials. Structural properties are included investigation of the measurements X-Ray Diffraction (XRD), Scan Electron Microscopy (SEM), Fourier Transform InfraRed spectroscopy (FTIR) and Atomic Force Microscopy (AFM) tests to the PbI2 thin films samples. Optical properties are included the investigation UV-Vis test of the thin film samples deposited on glass substrates and investigated the Absorption, Transmittance and evaluated energy gap (Eg = 2.3 eV).

Efficient approach for optical and morphologic characterization of hybrid perovskite films based on reflectance and transmittance measurements

2021 ◽  
Author(s):  
Jorge Caram ◽  
Maximiliano Senno ◽  
Luisa Cencha ◽  
Silvia Tinte ◽  
Raul Urteaga ◽  
...  
Keyword(s):  
Low Cost ◽  
Normal Incidence ◽  
Film Deposition ◽  
Morphological Properties ◽  
Efficient Procedure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hybrid Perovskite

Abstract Organo-inorganic perovskites have been intensively studied due to its potential application in low cost and great efficient energy conversion in solar cells. Despite the great improvement in the quality of organo-inorganic perovskite films, a wide dispersion into the same batch of perovskite-based devices keep being an obstacle to obtaining highly reproducible results. For that reason new and efficient strategies for testing deposition results is imperative for the next step. Here we present a simple and efficient procedure for characterizing the optical and morphological properties based on the simultaneous reflectance and transmittance measurements under normal incidence over a MAPbI3 film. The proposed method provides qualitative and quantitative morphological information associated with the film roughness as well as information about the position of the optical gap and possible contributions to the optical dispersion in the structure that can be used as a simple diagnostic tool to optimize the film deposition. Results are contrasted and validated with electronic and atomic force microscopy, as well as first-principles calculations.

Frequency-Modulated Non-contact Atomic Force Microscopy Study of Heat-Treated Oxide Surface with Organic Molecules

2006 ◽  
Vol 45 (3B) ◽  
pp. 2045-2048
Author(s):  
Shukichi Tanaka ◽  
Hitoshi Suzuki ◽  
Mitsuru Inada ◽  
Toshiya Kamikado ◽  
Shinro Mashiko
Keyword(s):  
Atomic Force Microscopy ◽  
Organic Molecules ◽  
Microscopy Study ◽  
Oxide Surface ◽  
Atomic Force Microscopy Study ◽  
Force Microscopy ◽  
Atomic Force ◽  
Heat Treated
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