Enhanced photodiode performance: Au/boron-dipyrromethene/n-Si/Ag structure unveiling high photosensitivity and efficiency

In this study, the classical boron-dipyrromethene (4,4- difuoro-4-borata-3a-azonia-4a-aza-s-indacene, BODIPY) unit (C1), its halogenated derivative (C2), and disytryl derivative (C3), which are known for their absorption properties in the near-infrared (NIR) region, were synthesized. Chemical and photophysical investigations were carried out to reveal the complex features of the molecules using a range of spectroscopic techniques and their energies were calculated by Density Functional Theory (DFT) with the same basis set. The BODIPY thin films were coated on n-Si substrates using a spin coater to examine the effect of interlayer on photodiode/photovoltaic properties and Au/BODIPY (C1, C2, C3)/n-Si/Ag photodiodes having rectifying behavior were fabricated. The thermionic emission theory (TET) and modified Norde's functions were utilized to determine the rectification ratio, ideality factor, series resistance, and barrier height values of diodes. The values of barrier height, ideality factor, and rectification ratio at +/- 2 V were calculated as 0.81 eV, 1.83 and 2.47x103 for the Au/C1/n-Si/Ag diode, 0.83 eV, 1.63, and 7.06 x103 for the Au/C2/n-Si/Ag diode and 0.84 eV, 1.51 and 2.14x104 for the Au/C3/ n-Si/Ag diode in the dark from the TET, respectively. The values of FF (%) and efficiency were calculated as 38 and 1.51 for the Au/C1/n-Si/Ag diode, 47 and 2.03 for the Au/C2/n-Si/Ag diode, and 56 and 3.68 for the Au/ C3/n-Si/Ag diode under 100 mW/cm2 illumination, respectively. With remarkable electrical properties, the Au/ C3/n-Si/Ag photodiode stood out among the others, performing better in both dark and light conditions. Therefore, the produced diodes based on the BODIPY thin film can be employed as photodiodes/photovoltaics in optoelectronic applications.