Omnidirectional and broadband optical absorption enhancement in small molecule organic solar cells by a patterned MoO₃/Ag/MoO₃ transparent anode

We designed and calculated a novel organic solar cell (OSC) with MoO₃/Ag/MoO₃ (MAM) grating as transparent anode and the patterned copper phthalocyanine (CuPc)/fullerence (C₆₀) as active layer. The numerical results indicate that a broadband, omnidirectional light absorption enhancement is realized by utilizing such a one-dimensional (1D) grating with core-shell structure. The total absorption efficiency of the active layer over the wavelength range from 400 to 900 nm is enhanced by 178.88%, 19.44% and 99.16% relative to the equivalent planar cell considering the weight of air-mass 1.5 global (AM 1.5G) solar spectrum at normally incident transverse magnetic (TM), transverse electric (TE) and TM/TE hybrid polarized light, respectively. The improved light trapping is attributed to the multiple modes hybridization of propagating surface plasmon polaritons (SPPs), localized surface plasmons (LSPs) and the strong coupling of SPP waves at TM polarization along with the Floquet modes at TE polarization. Furthermore, the proposed optimized architecture also exhibits an expected short-circuit current density (J_sc) with the value of 11.11 mA/cm² in theory, which is increased by 116.6% compared with that of the planar control device.