Printed Nanostructures for Organic Photovoltaic Cells and Solution‐Processed Polymer Light‐Emitting Diodes

We review the progress on printing‐based technologies for organic electronic devices, especially organic photovoltaic (OPV) cells and polymer light‐emitting diodes (PLEDs). First we discuss recent efforts to introduce interdigitated nanostructures on the order of tens of nanometers to the photoactive layers of OPV cells using nanoimprint lithography including a soft‐printing process developed in our research group that can easily produce sub‐20 nm scale organic semiconductor nanopillars. Second, we review solution‐processible printing technologies such as gravure printing, screen printing, blade coating, and slot–die coating for high‐throughput manufacturing of PLEDs.Illuminating results: This article reviews the progress on printing‐based technologies for organic electronic devices, especially organic photovoltaic (OPV) cells and polymer light‐emitting diodes (PLEDs), including solution‐processible printing technologies such as gravure printing, screen printing, blade coating, and slot–die coating for high‐throughput manufacturing.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111088/1/340_ftp.pd

Role of CsF on electron injection into a conjugated polymer

We studied electron injection from Al and Au cathodes into the conjugated polymer poly[2-methoxy,5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV). When a thin CsF layer is inserted between MEH-PPV and Al, a substantial enhancement in electron injection is observed. Insertion of the same layer between MEH-PPV and Au does not have a similar effect, indicating that the enhancement mechanism is specific to CsF and Al. Thin Cs layers enhance electron injection regardless of the cathode metal. A mechanism that explains these observations is proposed. © 2000 American Institute of Physics

Light emitting diodes based on a liquid-crystalline oxadiazole derivative

Materials that can simultaneously act as liquid crystals, charge transport agents and emitters are of interest for potential applications in organic light emitting diodes. We report on the fabrication and characterization of single and multilayer diodes from a liquid crystalline oxadiazole derivative in a standard device configuration. Epitaxial deposition was used to produce oriented layers that led to devices with improved electrical properties

Energetics at Doped Conjugated Polymer/Electrode Interfaces

n/aFunding Agencies|EU [287594]; Swedish Research Council Linnaeus grant LiLi-NFM; Swedish Research Council [2013-4022]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine; Advanced Functional Materials Center at Linkoping University</p

Role of Thick-Lithium Fluoride Layer in Energy Level Alignment at Organic/Metal Interface: Unifying Effect on High Metallic Work Functions

The function of approximate to 3-nm thick lithium fluoride (LiF) buffer layers in combination with high work function metal contacts such as coinage metals and ferromagnetic metals for use in organic electronics and spintronics is investigated. The energy level alignment at the organic/LiF/metal interface is systematically studied using photoelectron spectroscopy and the integer charge transfer model. The thick-LiF buffer layer is found to pin the Fermi level to approximate to 3.8 eV, regardless of the work function of the initial metal due to energy level bending in the LiF layer caused by depletion of defect states. At 3-nm thickness, the LiF buffer layer provides full coverage, and the organic semiconductor adlayers are found to physisorb with the consequence that the energy level alignment at the organic/LiF interface follows the integer charge transfer models predictions.Funding Agencies|European Commission [NMP3-SL-2011-263104]; SUNFLOWER (FP7-ICT-7) [287594]; Swedish Research Council [2013-4022]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine</p