Optical simulations of P3HT/Si nanowire array hybrid solar cells

Abstract

An optical simulation of poly(3-hexylthiophene) (P3HT)/Si nanowire array (NWA) hybrid solar cells was investigated to evaluate the optical design requirements of the system by using finite-difference time-domain (FDTD) method. Steady improvement of light absorption was obtained with increased P3HT coating shell thickness from 0 to 80 nm on Si NWA. Further increasing the thickness caused dramatic decrease of the light absorption. Combined with the analysis of ultimate photocurrents, an optimum geometric structure with a coating P3HT thickness of 80 nm was proposed. At this structure, the hybrid solar cells show the most efficient light absorption. The optimization of the geometric structure and further understanding of the optical characteristics may contribute to the development for the practical experiment of the promising hybrid solar cells.

Ultralow Optical and Electrical Losses via Metal‐Assisted Chemical Etching of Antireflective Nanograss in Conductive Mesh Electrodes

“…Figure compares the absorptions when light illuminates short and long SiNG. UV light generated electron–hole pairs mostly in the top portion of the SiNG [ 28,57 ] because of the shallow penetration depth. In the case of short SiNG, carriers generated by UV light were separated by the Schottky junction and collected before recombination.…”

Mie Resonance-Modulated Spatial Distributions of Photogenerated Carriers in Poly(3-hexylthiophene-2,5-diyl)/Silicon Nanopillars

“…As active materials for photovoltaic (PV) applications organic semiconductors have many advantages, including strong light absorption over a broad wavelength range, adjustable energy band alignment, and competitive fabrication costs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 . Despite such advantages, the extremely short exciton diffusion lengths in organic materials (usually <20 nm) limit efficient exciton dissociation to carriers at the junction interface and collection of carriers 1 2 .…”

“…In particular, Si nanostructures, such as nanopillars (NPs), nanowires, and nanoholes, coated with organic layers have attracted significant attention for high-efficiency OSH solar cells. The Si nanostructures can provide pathways for efficient carrier transportation because of the high mobility of Si and the large junction area in such devices can aid efficient exciton dissociation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 . Recently, suppression of the surface recombination of nanostructured OSH PV devices enabled notable improvement of their power conversion efficiency 8 9 10 11 12 13 14 .…”

“…demonstrated experimentally that the strongly scattered light from their NPs, which had a similar diameter and height as ours, coupled with the substrate and caused the broad-band AR effect 17 . Coating with a P3HT layer drastically decreases the reflection of both the planar and NP samples, because the real part of the refractive index of P3HT ( n P3HT ) is smaller than that of Si ( n Si ) over the whole measurement wavelength range 7 . Although the reflection of the P3HT coated NP sample is very similar to that of the coated planar sample, the spatial distributions of the incident light in the samples are very distinct.…”

“…Figure 4a ,b show the FDTD simulated optical generation rate ( G ) in the P3HT coated planar Si wafers and Si NP array samples under illumination ( λ : 450, 635, and 850 nm) with an incidence angle of 55°, analogous to the SPV measurement conditions. G , representing the number of photogenerated carriers at each point per unit time, is calculated using the equation , where n is the real part of the refractive index, k is the imaginary part of the refractive index, and E is the electric field 7 . The dielectric functions of P3HT and crystalline Si were taken from ref.…”