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.