Detectivity analysis for organic photodetectors

In this perspective letter, we report that there is a problem with a detectivity estimation method based on dark current measurement for organic photodiodes (OPDs). Based on dark current, calculated detectivity for fabricated OPD was 4.22 × 1013 cmHz1/2/W at 520 nm. However, calculated detectivity for OPD based on measured noise current was 8.4 × 1010 cmHz1/2/W at 520 nm. Therefore, we found that there are huge differences (more about 3 magnitudes of order) of detectivity calculations based on dark current measurement assumption and our noise measurement analysis. From the calculations of detectivities, it is concluded that noise current analysis should be addressed to clarify the organic photodiode characteristics