Efficient Blue Electroluminescence from a Single‐layer Organic Device Composed Solely of Hydrocarbons

Abstract

An interesting physical phenomenon, electroluminescence, that was originally observed with a hydrocarbon molecule has recently been developed into highly efficient organic light-emitting devices. These modern devices have evolved through the development of multi-element molecular materials for specific roles, and hydrocarbon devices have been left unexplored. In this study, we report an efficient organic light-emitting device composed solely of hydrocarbon materials. The electroluminescence was achieved in the blue region by efficient fluorescence and charge recombination within a simple single-layer architecture of macrocyclic aromatic hydrocarbons. This study may stimulate further studies on hydrocarbons to uncover their full potential as electronic materials.

Magneto-electroluminescence effects in the single-layer organic light-emitting devices with macrocyclic aromatic hydrocarbons

“…6 Pristine aromatic hydrocarbons were recently revisited by introducing a macrocyclization strategy toward the molecular design of organic light-emitting device (OLED) materials, and macrocyclic aromatic hydrocarbons (MAHs) were thus established as promising and unique materials for OLEDs. [7][8][9][10][11] One of the interesting features of the OLEDs with MAH such as [n]cyclo-meta-phenylene ([n]CMP, n = 5, 6) is their simple architecture. 11 Most of the conventional OLEDs are composed of several layers, such as a hole-transport layer, electron-transport layer, and hole-blocking layer, in addition to an emission layer.…”

“…[7][8][9][10][11] One of the interesting features of the OLEDs with MAH such as [n]cyclo-meta-phenylene ([n]CMP, n = 5, 6) is their simple architecture. 11 Most of the conventional OLEDs are composed of several layers, such as a hole-transport layer, electron-transport layer, and hole-blocking layer, in addition to an emission layer. On the other hand, the OLED with MAH has only light emission layer, the so-called single-layer OLED, which is significantly advantageous from the industrial point of view.…”

“…On the other hand, the OLED with MAH has only light emission layer, the so-called single-layer OLED, which is significantly advantageous from the industrial point of view. 11 Since this OLED with MAH has been recently developed, 11 single-layer OLED. The positive MEL effect at short wavelength and negative MEL effect at long wavelength in the spectrum were found.…”

[n]Cyclo‐3,6‐phenanthrenylenes: Synthesis, Structure, and Fluorescence

“…Finally, we measured the fluorescence spectra and their absolute quantum yields ( ϕ ) for all the congeners (Figure ). As indicated by the preceding solid‐state analysis, the fluorescence quantum yield of [3]CPhen 3,6 was substantially high, displaying ϕ =75 % in toluene. Efficient fluorescence was a common feature for most of the cyclic congeners, and the ϕ values were 80 %, 80 %, and 85 % for [5]‐, [7]‐, and [8]CPhen 3,6 , respectively.…”

“…Another congener with a non‐planar hoop shape was recently synthesized by connecting eight phenanthrenylene panels at the 3,9‐positions ([8]cyclo‐3,9‐phenanthrenylene; [8]CPhen 3,9 ), disclosing its unique stereoisomerism (Figure ) . Recently, we discovered the highly fluorescent nature of [3]CPhen 3,6 in the solid state and successfully fabricated an efficient fluorescent organic light‐emitting device (OLED) composed solely of hydrocarbon macrocycles . Its solid‐state fluorescence in a thin film of a [5]cyclo‐ meta ‐phenylene derivative recorded a notable quantum yield of 66 %, but an inherent quantum yield of the fluorescence of [3]CPhen 3,6 in the solution phase was not reported.…”