Simulation of Thin-Film Solar Cells

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					Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




                   Simulation of Thin-Film Solar Cells

                            Dipl.-Technomath. Christine Jandl

                 Erlangen Graduate School of Advanced Optical Technologies (SAOT)
                             Department of Computer Science 10 (LSS)
                                 University of Erlangen-Nuremberg


                                       18. November 2009




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Outline


     1 Simulation Requirement

     2 Calculation Method

     3 Structure

     4 Oblique Incident Light

     5 Results

     6 Outlook



HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Simulation Requirement




          • Solve Maxwell’s equations
                 ˆ
              iω E = 1           ˆ
                               × H − σEˆ
                 ˆ     1         ˆ   σ∗ ˆ
              iω H = − µ       ×E − µ H
                                                    abs,λ         P
          • Calculate quantum efficiency QE (λ) := P
                                                     in,λ

          • Calculate short-circuit current density
              JSC =               AM1.5 ∆λ eλ
                         λ QE (λ)Pλ        hc




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure     Oblique Incident Light   Results   Outlook




Calculation Method



          • Finite Integration Technique (FIT)
          • Staggered grid → periodic boundary conditions




          1D staggered grid                               3D staggered grid


HZB 18.11.2009                                                                                 C. Jandl
Simulation Requirement        Calculation Method     Structure     Oblique Incident Light   Results   Outlook




Structure

      3D - Simulation of Different Structures
          • Flat, rectangular, pyramidal
          • Integration of AFM scans




                         structure of a solar cell               AFM scan by Fraunhofer
                                                                 IST Braunschweig

HZB 18.11.2009                                                                                        C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Structure




      Discretization
          • Size of the computational domain: 2.5µm × 2.5µm × 2.4µm
          • Number of points depend on wavelength
              (λ = 550nm, ..., 1000nm): between 6 and 50 million points
              → High Performance Computing




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Structure




      AFM Scan
          • Original size: 5µm × 5µm
          • Mirrored due to periodicity
              → computational domain: 10µm × 10µm
              → too large computational domain!




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement    Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Structure


      AFM Scan
          • Size of random part of scan 1.2µm × 1.2µm
          • Mirrowed part → new simulation domain: 2.4µm × 2.4µm




                 original scan                             simulated scan




HZB 18.11.2009                                                                                C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Oblique Incident Light



 Until Now:                                          New:
 using periodic extension                            using phase shift




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement      Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Oblique Incident Light


      Comparison: Simulation vs. Experiment
      Quantum efficiency of a flat structured solar cell for different
      incident angles α




                         2D simulation                           experimental data



HZB 18.11.2009                                                                                  C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Results


      Simulation Data
          • Simulation with integrated AFM scan
          • Size of simulation domain: 2.4µm × 2.4µm × 2.38µm
          • Wavelength range: 550nm − 995nm
          • Distance: ∆λ = 5nm
          • Number of points: between 6 (995nm) and 46 millions (550nm)
          • Number of MPI processors: 1000
          • Average duration: 4 - 5 hours




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure       Oblique Incident Light    Results       Outlook




Results



 Quantum Efficiency                                    Short-Circuit Current Density
                                                                             Rand01    Rand02     Rand03
 different random domains per                                 h
                                                          JSC mA/cm2
                                                                     i
                                                                              8.982    9.242      9.125
 wavelength
                                                     → max derivation: 2.9%




HZB 18.11.2009                                                                                        C. Jandl
Simulation Requirement      Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Results




                         3D structure                            |E |2 (λ = 800nm)




HZB 18.11.2009                                                                                  C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Outlook


      Future Projects

          • Integration of silver nanoparticle
          • New implementation for oblique incident waves
          • Less memory capacity and computing time
          • Smaller wavelengths (start at 350nm)
          • Larger computational domain
          • Tandem solar cell (with integrated AFM scan)




HZB 18.11.2009                                                                               C. Jandl
Simulation Requirement   Calculation Method   Structure   Oblique Incident Light   Results   Outlook




Outlook



  Tandem Solar Cell
  Size of the computational
  domain:
  2.5µm × 2.5µm × 3.55µm




HZB 18.11.2009                                                                               C. Jandl