Self-Aligned Multifunction Diodes Using Ink-Jet Printing Method

We have investigated self- aligned multifunction diodes ( SA- MFDs) using an ink- jet printing ( IJP) method. The MFD is defined as the diode exhibits functions of emission and photo- sensing. A special organic material of pyrazoline derivative was dissolved and a solution was printed on a transparent indium- zinc- oxide ( IZO) coated glass substrate covered with an insulating poly- methylmethacrylate ( PMMA) layer. The PMMA was dissolved in a solvent. Then, organic materials were formed at the same position as that of the ink- jet- printed region, that is, SA- MFD was realized. For light emitting operation, a luminance obtained was 810 cd/m(2) under forward- biased condition. For photo- sensing operation under xenon lamp illumination, a photocurrent density was 0.84 mu A/cm(2) and the ratio of photoconductivity to dark conductivity was 10(2) under reverse- biased condition.