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

摘要

Magneto-electroluminescence (MEL) effects are observed in single-layer organic light-emitting devices (OLEDs) comprising only macrocyclic aromatic hydrocarbons (MAHs). The fluorescence devices were prepared using synthesized MAHs, namely, [ n ]cyclo- meta -phenylene ([ n ]CMP, n = 5, 6). The MEL ratio of the resulting OLED is 1%–2% in the spectral wavelength range of 400-500 nm, whereas it becomes negative (?1.5% to ?2%) in the range from 650 to 700 nm. The possible physical origins of the sign change in the MEL are discussed. This wavelength-dependent sign change in the MEL ratio could be a unique function for future single-layer OLEDs capable of magnetic-field-induced color changes.