Numerical simulation of a triple-junction thin-film solar cell based on μc-Si_1−xGe_x:H

Abstract

In this paper, a-Si:H/a-SiGe:H/μc-SiGe:H triple-junction solar cell structure is proposed. By the analyses of microelectronic and photonic structures (AMPS-1D) and our TRJ-F/TRJ-M/TRJ-B tunneling-recombination junction (TRJ) model, the most preferably combined bandgap for this structure is found to be 1.85 eV/1.50 eV/1.0 eV. Using more realistic material properties, optimized thickness combination is investigated. Along this direction, a-Si:H/a-SiGe:H/μc-SiGe:H triple cell with an initial efficiency of 12.09% (Voc = 2.03 V, FF = 0.69, Jsc = 8.63 mA/cm2, area = 1 cm2) is achieved in our laboratory.

β-FeSi2as the bottom absorber of triple-junction thin-film solar cells: A numerical study

“…[9] The temperature coefficients of the bandgaps of a-Si, µc-Si, and β -FeSi 2 are 4.7×10 −4 eV/K, [24] 4.2×10 −4 eV/K, [25] and 3.1×10 −4 eV/K, [26] respectively. The Yunaz model [27,28] of the tunnel-recombination junction for simulating the triplejunction solar cell is employed. The simulated illumination is AM 1.5G, 100 mW/cm 2 .…”

Band gap grading in microcrystalline silicon germanium thin film solar cells

“…Nowadays, the triple junction silicon based thin film solar cell shows the state of art of conversion efficiency of 16.1% for p-i-n type [6] and 16.3% for n-i-p type [7]. The theoretical analysis of triple junction silicon thin film solar cell suggested that an optimum band gap of the bottom sub-cell absorber should be 0.9 [8] or 1.0 eV [9] depending on the type of the top and middle sub-cells. However, the band gap of the hydrogenated microcrystalline silicon (µc-Si:H) that generally has been used as the bottom sub-cell absorber was 1.1 eV which is not the optimal value.…”

Light trapping characteristics of glass substrate with hemisphere pit arrays in thin film Si solar cells

“…[7] Many thin film Si solar cells have been demonstrated, including singlejunction hydrogenated amorphous silicon (a-Si), [4] tandemjunction amorphous/microcrystalline silicon, [8] and triplejunction amorphous silicon. [9,10] However, the thickness of the absorber layer for thin film silicon solar cells is only about hundreds or thousands of nanometers, which is not sufficient to absorb long wavelength light for solar spectrum. [11] Therefore, the power conversion efficiency (PCE) of thin film Si solar cells is relatively low compared with those of crystalline silicon and polycrystalline Si solar cells.…”