Stackable spectral-sensitive conductive films based on cyanine aggregates via an inkjet method

• Miniaturized organic photodiodes fabricated by a piezoelectric inkjet method.
• Spectral-resolving capability resulted from the J-aggregate formed during droplet drying.
• J-aggregate formation is improved at the lower dye concentration.
• Sensitivity of the photodiode is improved by 3 orders of magnitude at optimized dye concentration.
• Inkjet printed spots can be stacked without deteriorating the J-aggregate formation.

In this work, wavelength sensitive organic bulk-hetero photodiodes were fabricated by a piezoelectric inkjet method based on the J-type aggregates of cyanine dye molecules doped into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) thin films on indium tin oxide anodes. The cyanine dye concentration in the inkjet printed films was optimized and the J-aggregate formation during the drying process was investigated by local absorption spectra. It was found that at lower dye concentrations, not only the J-aggregate formation but also the radiation sensitivities of the films were improved significantly. Moreover, the stacking of the cyanine dye – poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) spots demonstrated the linear increase on the optical density and film thickness without deteriorating the J-aggregate formation, indicating their potential in application as narrow band filters.