Investigation of electroluminescence from Au/poly-4-dicyanomethylene-4H-cyclopenta[2,1-b:3,4-b′]dithiophene/porous Si/Si/Al light emitting diodes

We report simple porous silicon-based devices producing stable electroluminescence (EL) by the deposition of a poly-4-dicyanomethylene-4H-cyclopenta[2,1-${\text{b:3,4-b}}^{\prime }]$ dithiophene monolayer (PCDM) into the nanostructure. The structure of these devices is Au/PCDM/porous silicon/Si/Al. The EL emission is bright, visible by the naked eye under normal daylight, and broad in wavelength, covering the whole visible range with a peak at 650 nm. The emission area of the devices is $\text{1\hspace{0.5em}}{\mathrm{cm}}^{\mathrm{2}}.$ The EL starting voltage is in the range of 14–30 V and the current is around 300 mA. The time stability was good for all the devices tested. After exposure to the air for more than three months, the devices show nearly the same emission intensity without increase of external power supplied.