On the interplay of interface morphology and microstructure of high-efficiency microcrystalline silicon solar cells

Tamang, Asman; Sai, Hitoshi; Jovanov, Vladislav; Bali, Sardar I.H.; Matsubara, Koji; Knipp, Dietmar

doi:10.1016/j.solmat.2016.02.018

Cited by 21 publications

(41 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These cracks are generally recombination‐active, and likely formed by shadowing effect during the film growth owing to surface morphology. The detailed conditions for crack formation were also investigated using numerical simulations . Moreover, in the latter case, the front surface texture is flattened out to some extent, resulting in less efficient light in‐coupling and scattering.…”

Section: High‐efficiency Microcrystalline Solar Cellsmentioning

confidence: 99%

Key Points in the Latest Developments of High‐Efficiency Thin‐Film Silicon Solar Cells

Sai

Matsui

Matsubara

2017

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

Thin‐film silicon has been intensively used in photovoltaic applications. In recent years, most of the record efficiencies in thin‐film silicon solar cells have been updated frequently, particularly in microcrystalline silicon solar cells. In this article, key points in the latest developments of high‐efficiency thin‐film silicon solar cells are reviewed with a short overview of thin‐film silicon technology. The main driver for the efficiency improvement of microcrystalline silicon cells was the development of sophisticated light scattering substrates. The well‐designed honeycomb‐textured substrates enabled a systematic and detailed optimization to realize the growth of high‐quality films and significant light absorption enhancement simultaneously. The knowledge obtained about microcrystalline silicon solar cells and the insights regarding light‐induced degradation of a‐Si:H solar cells were successfully transferred to triple junction cells, which was demonstrated by the achievement of the record stabilized efficiency of 14%.

show abstract

Section: High‐efficiency Microcrystalline Solar Cellsmentioning

confidence: 99%

Key Points in the Latest Developments of High‐Efficiency Thin‐Film Silicon Solar Cells

Sai

Matsui

Matsubara

2017

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

show abstract

“…Texturing the interfaces affects not only the short‐circuit current density. The open‐circuit voltage and fill factor are affected too by changing the surface texture of microcrystalline silicon thin‐film solar cells . Microcrystalline silicon films grown on textured surfaces exhibit a high concentration of microstructure‐induced recombination centers, while the silicon films prepared on smooth surfaces do not exhibit such microstructure‐induced recombination centers .…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the crack formation affects the charge collection efficiency of the solar cells. Furthermore, the open‐circuit voltage and fill factor are affected . Hence, these electrical properties of the microcrystalline silicon solar cell have to be considered when optimizing its light‐trapping properties.…”

Section: Introductionmentioning

confidence: 99%

Tiling of Solar Cell Surfaces: Influence on Photon Management and Microstructure

Tamang

Sai

Jovanov

et al. 2017

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

optical losses. [8][9][10][11][12][13][14] Hence, both the quantum efficiency (QE) and short-circuit current density of the solar cells can potentially be enhanced when properly implemented. Several experimental and simulation approaches have been carried out to derive the optimal textured interfaces. [4,7,9,15] However, realization and modeling of the optimal textured interfaces are complex because several factors have to be considered. [4,7,9,15] In order to realize the solar cells with high energy conversion efficiency, it is necessary to maximize the product of short-circuit current density, open-circuit voltage, and fill factor. Texturing the interfaces affects not only the short-circuit current density. The open-circuit voltage and fill factor are affected too by changing the surface texture of microcrystalline silicon thinfilm solar cells. [2,7,[16][17][18][19][20][21][22][23][24][25][26] Microcrystalline silicon films grown on textured surfaces exhibit a high concentration of microstructure-induced recombination centers, while the silicon films prepared on smooth surfaces do not exhibit such microstructure-induced recombination centers. [16,18,[23][24][25][26] A high concentration of recombination centers is observed in regions with reduced structural order, often called "cracks" or "voids." The concentration of cracks increases with increasing roughness of the substrate. [14,16,18,[23][24][25][26] As a result, the crack formation affects the charge collection efficiency of the solar cells. Furthermore, the open-circuit voltage and fill factor are affected. [7,16,18,[22][23][24][25][26] Hence, these electrical properties of the microcrystalline silicon solar cell have to be considered when optimizing its light-trapping properties.The microcrystalline silicon (µc-Si:H) solar cells fabricated on hexagonal textured substrates exhibit the highest short-circuit current density of up to 32.9 mA cm −2 , and energy conversion efficiency up to 11.8%. [3,6] The highest short-circuit current density of 32.9 mA cm −2 is obtained for a 4 µm thick solar cell on a hexagonal textured substrate with period of 4 µm, while the highest energy conversion efficiency is obtained for a solar cell with a thickness of 1.7 µm on a hexagonal textured substrate with a period of 2.0 µm. [3,6] However, it remains unclear if hexagonal textured substrates represent the best possible substrate. Hence, in this study, the influence of different textured substrates on the QE, short-circuit current density, and formation of cracks is studied.In the following, the µc-Si:H solar cells with different substrate textures are compared in respect of the optical properties Microcrystalline silicon thin-film solar cells prepared on hexagonal tiled surfaces exhibit record short-circuit current densities and energy conversion efficiencies. However, it remains unclear if hexagonal textured substrates represent the best possible substrate tiling. In this study, hexagonal tiled substrates are compared with square and triangular tiled substrates in terms of...

show abstract

“…Similar challenges are known for other silicon thin-film technologies, e.g. nano-crystalline silicon (nc-Si) thin-film solar cells [12][13][14][15]. One successful approach for nc-Si solar cells in substrate configuration is the implementation of flat light scattering substrates (FLiSS) as lighttrapping structures [16][17][18][19].…”

Section: Introductionmentioning

confidence: 87%

Smooth anti-reflective three-dimensional textures for liquid phase crystallized silicon thin-film solar cells on glass

Eisenhauer

Köppel

Jäger

et al. 2017

Sci Rep

View full text Add to dashboard Cite

Recently, liquid phase crystallization of thin silicon films has emerged as a candidate for thin-film photovoltaics. On 10 μm thin absorbers, wafer-equivalent morphologies and open-circuit voltages were reached, leading to 13.2% record efficiency. However, short-circuit current densities are still limited, mainly due to optical losses at the glass-silicon interface. While nano-structures at this interface have been shown to efficiently reduce reflection, up to now these textures caused a deterioration of electronic silicon material quality. Therefore, optical gains were mitigated due to recombination losses. Here, the SMooth Anti-Reflective Three-dimensional (SMART) texture is introduced to overcome this trade-off. By smoothing nanoimprinted SiOx nano-pillar arrays with spin-coated TiOx layers, light in-coupling into laser-crystallized silicon solar cells is significantly improved as successfully demonstrated in three-dimensional simulations and in experiment. At the same time, electronic silicon material quality is equivalent to that of planar references, allowing to reach V oc values above 630 mV. Furthermore, the short-circuit current density could be increased from 21.0 mA cm−2 for planar reference cells to 24.5 mA cm−2 on SMART textures, a relative increase of 18%. External quantum efficiency measurements yield an increase for wavelengths up to 700 nm compared to a state-of-the-art solar cell with 11.9% efficiency, corresponding to a jsc, EQE gain of 2.8 mA cm−2.

show abstract

On the interplay of interface morphology and microstructure of high-efficiency microcrystalline silicon solar cells

Cited by 21 publications

References 38 publications

Key Points in the Latest Developments of High‐Efficiency Thin‐Film Silicon Solar Cells

Key Points in the Latest Developments of High‐Efficiency Thin‐Film Silicon Solar Cells

Tiling of Solar Cell Surfaces: Influence on Photon Management and Microstructure

Smooth anti-reflective three-dimensional textures for liquid phase crystallized silicon thin-film solar cells on glass

Contact Info

Product

Resources

About