Sputtering of metal oxide tunnel junctions for tandem solar cells

Johnson, Forrest; Song, Sung-Hyuk; Liptak, R. W.; Chernomordik, Boris D.; Campbell, Stephen A.

doi:10.1109/pvsc.2013.6744337

Cited by 5 publications

(1 citation statement)

References 38 publications

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“…We investigated the I-V characteristics of p-Cu 2 O/n-In 2 O 3 junction. Early experimental results show ohmic behavior at a similar junction made from p-Cu 2 O/n-ZnSnO 3 [18]. Here we also investigate monolithic CIGS- It is important to point out that major obstacles exist to realizing a high-efficiency tandem cell.…”

Section: Introductionmentioning

confidence: 93%

Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells

Song

Aydil

Campbell

2015

Solar Energy Materials and Solar Cells

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A metal-oxide broken-gap heterojunction between p-Cu 2 O and n-In 2 O 3 is proposed and studied for use as a tunnel junction in polycrystalline CuIn 1-x Ga x Se 2 (CIGS) based tandem solar cells using numerical device simulation. Specifically, a tandem solar cell with a CuGaSe 2 (CGS) absorber top cell and a CuInSe 2 (CIS) absorber bottom cell was considered. The ballistic transport model explains well the carrier transport in the broken-gap heterojunction. Broken-gap heterojunctions provide linear current-voltage characteristics even if one side is lightly doped and the junction resistance is much lower than typical values of series resistance in solar cells. However, electron affinities of metal oxides for broken-gap band alignment may induce an energy barrier between the tunnel junction and the top and bottom solar cells, degrading performance. These barriers can be reduced using buffer layers. For example, NiO and graded In 2 O 3-ZnO buffer layers are proposed beneath CGS top solar cell and above the CIS bottom solar cell, respectively. With these buffer layers, the efficiencies of the top and bottom cells are 17.5% and 6.5% respectively. The modeled efficiency of the CGS/CIS tandem solar cell is 24.1% and there is virtually no significant efficiency loss due to the presence of the broken-gap junction.

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Section: Introductionmentioning

confidence: 93%

Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells

Song

Aydil

Campbell

2015

Solar Energy Materials and Solar Cells

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Recent Progress in Interconnection Layer for Hybrid Photovoltaic Tandems

Park

Lee

et al. 2020

Advanced Materials

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larger acceptance owing to their decreasing cost. However, Si cells feature power conversion efficiencies (PCEs) close to the maximum practically achievable value (29.4% for crystalline Si solar cells), which makes it difficult to further reduce the levelized cost of electricity by decreasing the power output-to-cost ratio. [7,8] The most straightforward solution to this problem is to hybridize multiple semiconductor layers in a tandem architecture for absorbing the different wavelengths of the solar spectrum using different solar cell technologies. [9-12] As proven by a theoretical tandem cell efficiency of ≈46%, [13] Si solar cells with a bandgap of 1.1 eV have been regarded as potential bottom subcells of hybrid tandems, additionally offering the benefits of mass production suitability owing to well-organized production lines and global supply chains. [13,14] However, Sibased hybrid tandem solar cells configured with cost-effective solar cell technologies, including dye-sensitized solar cell (DSSC) and organic photovoltaics (OPV), have far lower efficiencies than single-junction Si solar cells, predominantly because of the insufficient compatibility of the employed materials with Si solar cells. [15-19] Metal halide perovskite-based solar cells have attracted significant attention in recent years because of their potential to be processed at low cost, high efficiencies, excellent optoelectronic properties, and tunable bandgap. They have therefore considered as prospective components of hybrid tandems. [20] Previous studies on the fundamental working principle of the hydrogenated amorphous Si (a-Si:H)/a-Si:H tandem and related validation by empirical investigations show the feasibility of combining different solar cell technologies, [6,21-23] as exemplified by the pairing of high-bandgap perovskite subcells with low-bandgap Si subcells or the assembly of dual perovskitebased tandem solar cells exploiting perovskite bandgap tunability. [14,24-26] To date, considerable effort has been directed at the development of wide-bandgap perovskite solar cells (PSCs) (1.65-1.8 eV) for hybrid tandem applications, [27,28] and remarkable progress (i.e., a high open-circuit voltage (V oc) of 1.31 V with a wide bandgap of 1.72 eV (>90% of the Shockley-Queisser limit)) has been achieved. [29] Currently, researchers aim to realize perovskite-based hybrid tandem solar cells with PCEs of 30%. Nonetheless, considerable electrical property and fabrication process adjustments are required to integrate singlejunction perovskites into the hybrid tandem architecture. The introduction of an intermediate layer to bridge different solar Hybrid tandem solar cells offer the benefits of low cost and full solar spectrum utilization. Among the hybrid tandem structures explored to date, the most popular ones have four (simple stacking design) or two (terminal/tunneling layer addition design) terminal electrodes. Although the latter design is more cost-effective than the former, its widespread application is hindered by the difficulty of preparing...

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