Search results for "organic semiconductor"

Low intrinsic carrier density LSMO/Alq3/AlOx/Co organic spintronic devices

2018

The understanding of spin injection and transport in organic spintronic devices is still incomplete, with some experiments showing magnetoresistance and others not detecting it. We have investigated the transport properties of a large number of tris-(8-hydroxyquinoline)aluminum-based organic spintronic devices with an electrical resistance greater than 5 MΩ that did not show magnetoresistance. Their transport properties could be described satisfactorily by known models for organic semiconductors. At high voltages (>2 V), the results followed the model of space charge limited current with a Poole-Frenkel mobility. At low voltages (∼0.1 V), that are those at which t…

Inside Front Cover: Long-Living Light-Emitting Electrochemical Cells - Control through Supramolecular Interactions (Adv. Mater. 20/2008)

2008

Chemical and Structural Trends in the Spin-Admixture Parameter of Organic Semiconductor Molecules

2019

Spin mixing in organic semiconductors is related to spin–orbit coupling (SOC). However, a detailed study analyzing the dependence of the spin-admixture parameter (γ) on structural and material para...

Improving the Robustness of Organic Semiconductors through Hydrogen Bonding

2021

Molecular organization plays an essential role in organic semiconductors since it determines the extent of intermolecular interactions that govern the charge transport present in all electronic applications. The benefits of hydrogen bond-directed self-assembly on charge transport properties are demonstrated by comparing two analogous pyrrole-based, fused heptacyclic molecules. The rationally designed synthesis of these materials allows for inducing or preventing hydrogen bonding. Strategically located hydrogen bond donor and acceptor sites control the solid-state arrangement, favoring the supramolecular expansion of the π-conjugated surface and the subsequent π-stacking as proved by X-ray d…

Influence of organic material and sample parameters on the surface potential in Kelvin probe measurements

2019

Financial support provided by ERDF 1.1.1.1 activity project Nr. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices” as well as Scientific Research Project for Students and Young Researchers Nr. SJZ2016/20 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged.

Nanoimprint lithography for organic electronics

2002

Thin films made of organic semiconductors (α-sexithiophene, PDAS and PBAS) have been printed and the impact on morphology studied by optical, atomic force and electron microscopy. Surfaces in contact with the stamp during printing undergo a change towards smoother and more ordered material at the macromolecular scale. Interdigitated nanoelectrodes to be used as source and drain in TFTs have been made and printed down to 100 nm. PDAS and PBAS can be printed at room temperature and preserve their printed feature provided they are cross-linked afterwards.

Bulk heterojunctions by boramers for plastic photovoltaics

2009

Giant Spin Seebeck Effect through an Interface Organic Semiconductor

2019

Interfacing an organic semiconductor C60 with a non-magnetic metallic thin film (Cu or Pt) has created a novel heterostructure that is ferromagnetic at ambient temperature, while its interface with a magnetic metal (Fe or Co) can tune the anisotropic magnetic surface property of the material. Here, we demonstrate that sandwiching C60 in between a magnetic insulator (Y3Fe5O12: YIG) and a non-magnetic, strong spin-orbit metal (Pt) promotes highly efficient spin current transport via the thermally driven spin Seebeck effect (SSE). Experiments and first principles calculations consistently show that the presence of C60 reduces significantly the conductivity mismatch between YIG and Pt and the s…

2015

Electrically detected magnetic resonance (EDMR) is a commonly used technique for the study of spin-dependent transport processes in semiconductor materials and electro-optical devices. Here, we present the design and implementation of a compact setup to measure EDMR, which is based on a commercially available benchtop electron paramagnetic resonance (EPR) spectrometer. The electrical detection part uses mostly off-the-shelf electrical components and is thus highly customizable. We present a characterization and calibration procedure for the instrument that allowed us to quantitatively reproduce results obtained on a silicon-based reference sample with a “large-scale” state-of-the-art instru…

2017

The adsorption of molecular acceptors is a viable method for tuning the work function of metal electrodes. This, in turn, enables adjusting charge injection barriers between the electrode and organic semiconductors. Here, we demonstrate the potential of pyrene-tetraone (PyT) and its derivatives dibromopyrene-tetraone (Br-PyT) and dinitropyrene-tetraone (NO2-PyT) for modifying the electronic properties of Au(111) and Ag(111) surfaces. The systems are investigated by complementary theoretical and experimental approaches, including photoelectron spectroscopy, the X-ray standing wave technique, and density functional theory simulations. For some of the investigated interfaces the trends expecte…