Boosting photocurrent of GaInP top-cell for current-matched III–V monolithic multiple-junction solar cells via plasmonic decahedral-shaped Au nanoparticles

Abstract

Unbalanced photocurrent output for each sub-cell in monolithic multiple junction solar cells (MMJ-SCs) reduces the achievable photovoltaic power efficiency (PCE). Here, we first introduce Au decahedra nanoparticles to realize the plasmon-enhanced photo-absorption of GaInP top-cell and achieve the current-matched MMJ-SCs. By simply spin-coating the Au decahedral nanoparticles on the illuminated surface of the devices, the PCEs of the monolithic double junction and triple junction solar cells increase significantly from 27.01% to 28.63% and from 29.88% to 31.90%, respectively. Both the theoretical local electromagnetic distributions and the experimental extinction properties confirm the plasmonic induced absorption enhancement in device performance, and further elucidate the essential reason for photocurrent enhancement derives from the more furious oscillation of free electrons in the vicinity of sharp vertexes for Au decahedra nanoparticles. Our results demonstrate that Au decahedra with sharp vertexes and edges are promising for meliorating the trade-off between light absorption and carrier collection in GaInP top-cell. In addition, this facile and simple strategy also highlights non-annealing treatment and prevents the impurity diffusion at high temperature for MMJ-SCs, and may facilitate other types of solarharvesting devices.

Gallium nanoparticles as antireflection structures on III-V solar cells

“…Interestingly, by using Ag and Au, the plasmonic metals most commonly used as ARC, only up to 8% of JSC enhancement has been achieved experimentally [53][54][55][56]. Both metals have a very important disadvantage that is hardly mentioned in the publications: their plasma frequency is placed in the VIS-IR region.…”

Light‐trapping and spectral modulation to increase the conversion efficiency of triple‐junction GaAs solar cells using antireflective coating comprising a periodic array of cone‐shaped TiO 2 structures

“…Multilayer anti-reflective coatings with graded-index, refractive index, or high-low refractive index could conceivably be used to distribute light among sub-cells. [28][29][30][31][32] Nevertheless, light-trapping is generally more difficult in multiple-junction solar cells than in single-junction solar cells, 33,34 due to the need to preserve broadband absorption and deal with the issue of photo-current mismatch between sub-cells. In the current study, we developed a novel antireflective coating with surface nano-structures to enhance current matching and conversion efficiency in the top and middle cells of triplejunction (3 J) GaAs solar cells.…”

“…Unfortunately, process variation during the epitaxial growth stage makes it difficult to match current perfectly among all sub‐cells. Multilayer anti‐reflective coatings with graded‐index, refractive index, or high‐low refractive index could conceivably be used to distribute light among sub‐cells 28‐32 . Nevertheless, light‐trapping is generally more difficult in multiple‐junction solar cells than in single‐junction solar cells, 33,34 due to the need to preserve broadband absorption and deal with the issue of photo‐current mismatch between sub‐cells.…”