Highly efficient poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate)/ Si hybrid solar cells with imprinted nanopyramid structures

High-efficiency hybrid solar cells based on nanostructured silicon and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), which were fabricated via a simple nanoimprint fabrication process, demonstrated an excellent power conversion efficiency of 10.86%. The complex and costly high-temperature photolithography and masking steps were replaced by techniques that are low-cost and capable of mass production. The nanopyramid structures fabricated on the silicon surface provided an antireflective effect and have a radial junction architecture that enhanced the light absorption and carrier collection efficiency. The short-circuit current density (J_sc) of the hybrid solar cell with nanopyramid structures was greatly improved from 24.5 mA/cm ² to 32.5 mA/cm² compared with that of a flat surface device. The highest solar cell efficiency was achieved on a 525 μm-thick 2.3 Ω cm n-type Czochralski process (CZ) Si substrate with a designated area of 4 cm².