Electroluminescence in organics

Abstract

There is growing interest in organic electroluminescence (EL). A great deal of progress has been made recently in improving the performance of various classes of organic EL devices. Some of these are now adequate for many applications. However, specialists focusing on selected aspects of organic EL devices have often lost contact with the general subject of EL. Therefore, a review covering all aspects of EL mechanisms and their experimental manifestation seemed necessary. This article is concerned with the new EL device physics that can be realized using crystals, or films made of organic materials, as electrically and optically active components, in devices ranging from simple single-component light emitting diodes (LEDs), through double-and multi-layer LEDs to light emitting electrochemical cells (LECs) and organic LED-based light transducers. The investigation of the properties of these devices has provided in turn a very effective method for studying the basic EL phenomena in these materials. Since the subject of the present review has generated a huge amount of literature, and it is impossible to mention here all that has been done, we have attempted to provide an outline of the background of the field of organic EL, and discussed in some detail those aspects most relevant to the EL device physics. Because of the diversity of the types of material and EL structure, there is no single, simple description of EL in organics. Therefore, the initial sections of the article are devoted to a discussion of the types of EL and related phenomena, such as carrier injection and recombination or nature of emitting states. Then, the fundamentals of the fabrication of various types of EL devices are discussed along with the most representative examples. In general, the reader will find in the article a brief historical review of the subject as well as a description of the latest trends in organic EL research covering all the new concepts and most important data which have become available before the time of publication.

Morphological changes and proteome response of Corynebacterium glutamicum to a partial depletion of FtsI

“…Complete genome sequence information of two strains of C. glutamicum ATCC 13032 is available, NC_003450 (Ikeda & Nakagawa, 2003) and BX927154 (Kalinowski et al, 2003), and the region of the dcw cluster is shown in Fig. 1(a).…”

Organic light emitting diodes with spin polarized electrodes

“…5 Our geometry for the standard OLED consists of ITO as hole injector, N,NЈ-diphenyl-N,NЈ-(3-methilphenyl)-1, 1Ј-biphenil-4,4Јdiamine ͑TPD͒ as hole transporting layer ͑70 nm͒, 8-hydroxyquinoline aluminum (Alq 3 ) as emitting layer ͑70 nm͒, LiF ͑2 nm͒ tunnel barrier, and Al cathode. 1 The manganite work function LSMO is about 4.7-4.9 eV and is similar to that of ITO ( ITO ϳ5 eV) allowing the ITOmanganite substitution ͑Fig. 1͒.…”

“…A great effort has been made to enhance the device luminescence working on metal-organic interfaces, morphology, and charge transport in organic material. 1 Radiative recombination in OLEDs based on undoped -conjugated molecules arises from singlet excitons annihilation ͑triplet excitons normally do not contribute to photon emission͒. 2 The manipulation of the spin of carriers allows one to tune the electroluminescence ͑EL͒ efficiency by changing the relative population of singlet/triplet excitons.…”

Chargino production and decay in photon–photon collisions

“…Several studies analyze the determination of the gaugino mass parameter M 1 via production and subsequent leptonic decay of neutralinos or selectrons in e + e − annihilation [10] - [15], via selectron production in e − e − scattering [15,16] or via associated selectron neutralino (LSP) production in eγ scattering processes [17,18]. In all these processes the M 1 dependence of the cross sections of the decay leptons, their polarization and forward-backward asymmetries result from a complex interplay of the M 1 dependence of the respective production and decay mechanism.…”