Incorporation of SiO2 dielectric nanoparticles for performance enhancement in P3HT:PCBM inverted organic solar cells

•SiO2 nanoparticles were incorporated into the photoactive and electron transport layers.•The efficiency and charge carrier concentration have been increased in SiO2 embedded devices.•The best results obtained in 50 nm SiO2 nanoparticles embedded devices.•All the improvements are due to Mie scattering and total internal reflection of light.•The lower mobility restricted them to provide significantly high performance parameters.

It is well known that organic solar cells (OSCs) with inverted geometry have not only demonstrated a better stability and longer device life time but also have shown improved power conversion efficiency (PCE). Recent studies exhibit that incorporation of metal and/or semiconducting nanoparticles (NPs) can further increase the PCE for OSCs. In this present work, we have synthesized SiO2 NPs of various sizes (25, 50, 75 and 100 nm) using the modified Stober method and incorporated them into P3HT:PCBM photoactive layer and ZnO based electron transport layer (ETL) in order to investigate the light trapping effects in an OSC. Absorption studies have shown a considerable increase in photo absorption in both cases. The fabricated devices demonstrated 13% increase in the PCE when SiO2 NPs are incorporated in P3HT:PCBM photoactive layer, whereas PCE was increased by 20% when SiO2 NPs are incorporated in ZnO based ETL. Mott–Schottky analysis and impedance spectroscopy measurements have been carried out to determine the depletion width and global mobility for both the devices. The possible reason for PCE enhancement and the role of SiO2 NPs in active layer and ZnO ETL are explained on the basis of the results obtained from Mott–Schottky analysis and impedance spectroscopy measurements.

Graphical abstractVarious sizes of silica nanoparticles (SiO2 NPs) have been successfully synthesized and incorporated them into the photoactive layer of P3HT:PCBM bulk heterojunction as well as in ZnO electron transport layer to enhance the optical absorption and power conversion efficiency in inverted organic solar cells.Figure optionsDownload full-size imageDownload as PowerPoint slide