Electrochemical Tuning of Morphological and Optoelectronic Characteristics of Donor–Acceptor Spiro-Fluorene Polymer Film. Application in the Building of an Electroluminescent Device

Abstract

The electrochemical polymerization conditions for the synthesis of spirobifluorene-based polymer (EF-CN1) films with adequate properties to be applied in an organic light emitting diode (OLED) were studied. We demonstrate that, after optimization in the parameters of electrochemical polymerization, we were able to obtain a conducting polymeric film with very smooth surface, absence of pinholes, and high optoelectronic activity, which was compatible as an efficient hole transporting layer in OLED. The electrochemical deposited polymers, and polymer films obtained through drop casting from solution of chemically synthesized polymer (C-CN1), were characterized and the results compared. The films were studied by cyclic voltammetry, UV–vis, fluorescence spectra, scanning electron mictroscopy, and atomic force microscopy. The built OLEDs achieve current-luminous efficiency and external quantum efficiency of 2.6 cd/A and 0.50%, respectively.

Electron Donor‐Acceptor Spirobi[cyclopenta[2,1‐b : 3,4‐b′]dithiophene] Derivatives as Precursors of Electrodeposited Regioregular Thiophene‐based Polymers

“…Even though there are many classical examples of electrodeposited polymer films, such as those obtained from anilines, pyrroles, carbazoles, and thiophenes, examples bound to spiro‐linked molecular structures are less common. Most of the spiro‐molecules specifically designed to electrochemically form films are based on the 9,9’‐spirobifluorene core, with applications in OLEDs, [6] electrochromic devices, [27,28] and electronic paper [29] . More recently, this research field has been expanded by introducing heteroaromatic spiro‐skeleton cores with different optic and electronic characteristics [12,30,31] .…”

“…On the other hand, the optoelectronic properties of solid-state systems are more defined with respect to the case of analogous nonspiro compounds, being more similar to those observed at the molecular level, and they can be finely tuned by selecting adequate A and D functionalities, together with the nature and the length of the conjugated bridges. [2,4,5] Thanks to the combination of these notable properties, spiro-configured organic functional materials, mostly derived from 9,9'-spirobifluorene, have found potential use in several optoelectronic and electronic applications, including electrochemiluminescence, [3] organic light-emitting devices (OLEDs), [6] field-effect transistors, [7] lasers, [8] and solar cells. [9][10][11] However, spiro compounds based on heteroaromatics are increasingly investigated in optoelectronic devices, especially as p-organic semiconductors with improved charge injecting and transporting properties.…”

Improving the Electropolymerization Properties of Fluorene-Bridged Dicarbazole Monomers through Polyfluoroalkyl Side Chains

“…Inexpensive fluorene and carbazole derivatives are fit to this purpose. Indeed, conjugated materials featuring carbazole units either in the π-conjugated backbone or as pendant groups display excellent thermal and photochemical stabilities and possess high charge carrier mobility, making them attractive materials for a variety of applications. − In an analogous way, fluorene and 9,9′-spirobifluorene derivatives showing high photoluminescence (PL) quantum yields and electroluminescence (EL) efficiencies, as well as high thermal stabilities, have drawn much attention. ,,− Finally, fluorene and carbazole units can be combined in the same molecular structure leading to a variety of compounds with interesting hole transporting and electroluminescence properties. − …”

Luminescent network film deposited electrochemically from a carbazole functionalized AIE molecule and its application for OLEDs

“…[10][11][12][13] The EP technique combines the in situ synthesis and deposition of polymer films onto the destination electrodes in one step, and is highly attractive due to its simplicity and low-cost. 14 The growth rate, thickness and the morphology of the EP films can be easily optimized through EP conditions, including preparation techniques and optimization of the experimental parameters. 15 For developing an effective method to construct functional polymer films, it is important to explore the influence of the precursor properties on the structure and properties of the resultant EP films and devices.…”