Calibrated Dielectric Fiber Arrays for Light-Trapping Enhancement in Organic Solar Cells

A numerical investigation of an array consisting of SiO₂ fibers to generate whispering gallery modes (WGMs) and lensing effects atop an organic solar cell (OSC) to enhance optical absorption efficiency is reported. SiO₂ fibers calibrated to generate the optimal WGM resonator (WGMR) and antireflection coating for broadband light account for increases in integrated absorption up to 16% when compared with its flat-OSC counterpart. The overall absorption, using AM1.5 G (air mass 1.5 global) spectra, yields absorption efficiencies of 60% in an optimal configuration with a cell size of 600 nm and fiber radius of 200 nm. Using fibers like the WGMR and antireflector, it is seen that there is a broadband absorption over all wavelengths, except for 380-400 nm, when using this substrate.