Absorption loss at nanorough silver back reflector of thin-film silicon solar cells

Špringer, J.; Poruba, A.; Müllerová, Ludmila; Vaněček, M.; Kluth, O.; Rech, Bernd

doi:10.1063/1.1633652

Cited by 221 publications

(153 citation statements)

References 10 publications

Supporting

Mentioning

139

Contrasting

Unclassified

Order By: Relevance

“…This fact has also been reported in other studies [11] and a similar increase in the absorption of rough silver layers respect to smooth ones has been measured by means of Photothermal Deflection Spectroscopy (PDS) [12].…”

Section: Resultssupporting

confidence: 66%

Spectral analysis of the angular distribution function of back reflectors for thin film silicon solar cells

Escarré¹,

Villar²,

Asensi³

et al. 2006

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

Nowadays, one of the most important challenges to enhance the efficiency of thin film silicon solar cells is to increase the short circuit intensity by means of optical confinement methods, such as textured back-reflector structures. In this work, two possible textured structures to be used as back reflectors for n-i-p solar cells have been optically analysed and compared to a smooth one by using a system which is able to measure the angular distribution function (ADF) of the scattered light in a wide spectral range (350-1000 nm). The accurate analysis of the ADF data corresponding to the reflector structures and to the µc-Si:H films deposited onto them allows the optical losses due to the reflector absorption and its effectiveness in increasing light absorption in the µc-Si:H layer, mainly at long wavelengths, to be quantified.

show abstract

Section: Resultssupporting

confidence: 66%

Spectral analysis of the angular distribution function of back reflectors for thin film silicon solar cells

Escarré¹,

Villar²,

Asensi³

et al. 2006

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

show abstract

“…This substrate reduces texture mediated plasmon absorption [25][26][27] in the metallic back reflector and thus diminishes the optical losses, but thanks to the LP-CVD ZnO, it supplies a sufficient amount of roughness for light trapping in the absorber. Similarly, it has been reported in a pin solar cell 28 that the configuration with a smoothed metallic back reflector has optical advantages compared to rough back reflector.…”

Section: Discussionmentioning

confidence: 99%

Optimization of amorphous silicon thin film solar cells for flexible photovoltaics

Söderström

Haug

Terrazzoni-Daudrix

et al. 2008

Journal of Applied Physics

156

View full text Add to dashboard Cite

We investigate amorphous silicon ͑a-Si: H͒ thin film solar cells in the n-i-p or substrate configuration that allows the use of nontransparent and flexible substrates such as metal or plastic foils such as polyethylene-naphtalate ͑PEN͒. A substrate texture is used to scatter the light at each interface, which increases the light trapping in the active layer. In the first part, we investigate the relationship between the substrate morphology and the short circuit current, which can be increased by 20% compared to the case of flat substrate. In the second part, we investigate cell designs that avoid open-circuit voltage ͑V oc ͒ and fill factor ͑FF͒ losses that are often observed on textured substrates. We introduce an amorphous silicon carbide n-layer ͑n-SiC͒, a buffer layer at the n / i interface, and show that the new cell design yields high V oc and FF on both flat and textured substrates. Furthermore, we investigate the relation between voids or nanocrack formations in the intrinsic layer and the textured substrate. It reveals that the initial growth of the amorphous layer is affected by the doped layer which itself is influenced by the textured substrate. Finally, the beneficial effect of our optical and electrical findings is used to fabricate a-Si: H solar cell on PEN substrate with an initial efficiency of 8.8% for an i-layer thickness of 270 nm.

show abstract

“…Thus, this simplification leads to an underestimation of the enhancement factor, especially since it also does not consider reduced light intensity by absorption losses in the rough ZnO / Ag back reflector 43,44 and doped silicon layers. Figure 13 shows the f values calculated from the data shown in Fig.…”

Section: ͑1͒mentioning

confidence: 99%

“…This will underestimate the influence of absorption losses at the back reflector, since rough ZnO / Ag layers used in solar cells show higher parasitic absorptions. 43,44 In Table II quantum efficiencies at = 0.9 m and cell current densities in the spectral region of 650-1100 nm are given for front contact TACs of 0.5 and 1 wt %. Even though the calculation based on Eq.…”

Section: ͑3͒mentioning

confidence: 99%

The effect of front ZnO:Al surface texture and optical transparency on efficient light trapping in silicon thin-film solar cells

Berginski

Hüpkes

Schulte

et al. 2007

Journal of Applied Physics

488

275

View full text Add to dashboard Cite

This study addresses the material properties of magnetron-sputtered aluminum-doped zinc oxide (ZnO:Al) films and their application as front contacts in silicon thin-film solar cells. Optimized films exhibit high conductivity and transparency, as well as a surface topography with adapted light-scattering properties to induce efficient light trapping in silicon thin-film solar cells. We investigated the influence on the ZnO:Al properties of the amount of alumina in the target as well as the substrate temperature during sputter deposition. The alumina content in the target influences the carrier concentration leading to different conductivity and free carrier absorption in the near infrared. Additionally, a distinct influence on the film growth of the ZnO:Al layer was found. The latter affects the surface topography which develops during wet-chemical etching in diluted hydrochloric acid. Depending on alumina content in the target and heater temperature, three different regimes of etching behavior have been identified. Low amounts of target doping and low heater temperatures result in small and irregular features in the postetching surface topography, which does not scatter the light efficiently. At higher substrate temperatures and target doping levels, more regularly distributed craters evolve with mean opening angles between 120° and 135° and lateral sizes of 1–3μm. These layers are very effective in light scattering. In the third regime—at very high substrate temperatures and high doping levels—the postetching surface is rather flat and almost no light scattering is observed. We applied the ZnO:Al films as front contacts in thin-film silicon solar cells to study their light-trapping ability. While high transparency is a prerequisite, light trapping was improved by using front contacts with a surface topography consisting of relatively uniformly dispersed craters. We have identified a low amount of target doping (0.5–1wt%) and relatively high substrate temperatures (about 350–450°C as sputter parameters enabling short-circuit current densities as high as 26.8mA∕cm2 in μc-Si:H pin cells with an i-layer thickness of 1.9μm. Limitations on further improvements of light-trapping ability are discussed in comparison with the theoretical limitations and Monte Carlo simulations presented in the literature.

show abstract

Absorption loss at nanorough silver back reflector of thin-film silicon solar cells

Cited by 221 publications

References 10 publications

Spectral analysis of the angular distribution function of back reflectors for thin film silicon solar cells

Spectral analysis of the angular distribution function of back reflectors for thin film silicon solar cells

Optimization of amorphous silicon thin film solar cells for flexible photovoltaics

The effect of front ZnO:Al surface texture and optical transparency on efficient light trapping in silicon thin-film solar cells

Contact Info

Product

Resources

About