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 hightemperature 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/cm 2 compared with that of a flat surface device. The highest solar cell efficiency was achieved on a 525 lm-thick 2.3 X cm n-type Czochralski process (CZ) Si substrate with a designated area of 4 cm 2 .

ABSTRACT:We demonstrate the implementation of a hybrid solar cell that comprises a surface nanostructured ntype Si and poly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate). The Si surface before deposition of the organic layer was nanostructured by using CsCl self-assembled nanoparticles as a hard mask and dry etching to form radial junction architectures and enhance light diffusion and absorption. Apart from the textured Si surface, processing parameters such as from metal-electrode shadow ratio, spincoating rate, and surfactant addition were properly adjusted to improve overall cell performance. Our hybrid solar cells achieve the best performance under optimized cell parameters with a power conversion efficiency of 8.84% and short-circuit current density of 30.5 mA/cm 2 . This combined technique provides a simple, scalable, and cost-effective process for fabricating hybrid solar cells.

An ITO substrate with periodic surface nanostructures was used to induce strong diffusion and diffraction of incident light. The nanostructures were fabricated using nanoimprint lithography on photoresist followed by coating of the ITO layer and organic materials with uniform morphology. The nanostructures embedded into the ITO layer were found to increase absorption in poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester solar devices. The short-circuit current of the nanostructured organic solar cells improved from 7.07 to 10.76 mA/cm2. This improvement was due to the increased effective optical path of absorbed light resulting from the trapping and scattering by the nanostructures.