Improving NIR sensor detectivity of BODIPY/C60 bulk heterojunction photodiode

Abstract

We report a new near infrared (NIR) absorbing dye, phenyl-fused dibenzo-BODIPY with benzo[1,3,2]oxazaborinine rings (PhBODIPY), for organic photodiode (PDs). PhBODIPY can be deposited on the substrates without thermal decomposition and its deposited film is amorphous state with high thermal stability. The deposited film showed broadband absorption in the wavelength range of 6001000 nm. The NIR-OPD with PhBODIPY neat film demonstrated a detectivity (D∗) of 7.41 1011 Jones under NIR light irradiation at a wavelength of 820 nm. The D∗ improved to 1.70 1012 Jones by co-deposition of 1:1 (w/w) PhBODIPY:fullerene (C60). The photocurrent was maximized under light irradiation at a wavelength of 694 nm, corresponding to the absorption wavelength of H aggregated state of PhBODIPY molecules. The formation of H aggregated state is important to further improve OPD characteristics.