Suppressing lossy-film-induced angular mismatches between reflectance and transmittance extrema: optimum optical designs of interlayers and AR coating for maximum transmittance into active layers of CIGS solar cells

A new method combining in-situ real-time spectroscopic ellipsometry and optical modeling to optimize the thickness of an anti-reflective (AR) coating for Cu(In,Ga)Se2 (CIGS) solar cells is described and applied directly to fabricate devices. The model is based on transfer matrix theory with input from the accurate measurement of complex dielectric function spectra and thickness of each layer in the solar cell by spectroscopic ellipsometry. The AR coating thickness is optimized in real time to optically enhance device performance with varying thickness and properties of the constituent layers. Among the parameters studied, we notably demonstrate how changes in thickness of the CIGS absorber layer, buffer layers, and transparent contact layer of higher performance solar cells affect the optimized AR coating thickness. An increase in the device performance of up to 6% with the optimized AR layer is demonstrated, emphasizing the importance of designing the AR coating based on the properties of the device structure.

Download Full-text

Light-Induced Degradation in Solar Cells with Hydrogenated Amorphous Silicon-Sulfur Active Layers

MRS Proceedings ◽

10.1557/proc-715-a11.4 ◽

2002 ◽

Vol 715 ◽

Author(s):

Wei Xu ◽

P. C. Taylor

Keyword(s):

Solar Cells ◽

Practical Importance ◽

Chemical Vapor ◽

Photovoltaic Devices ◽

Sulfur Concentration ◽

Active Layers ◽

Conversion Efficiencies ◽

Hydrogenated Amorphous ◽

Secondary Ion ◽

Initial Conversion

AbstractWe have made a series of a-SiSx:H based solar cells, with a pin structure, in a multichamber plasma enhanced chemical vapor deposition (PECVD) system. The sulfur concentration ranges from zero to 5 x 1018 cm-3 as measured by secondary ion mass spectroscopy. The initial conversion efficiencies of cells in this series with sulfur concentrations ≤ 1018 cm-3 are approximately 7%. The time constants for degradation increase with increasing sulfur concentration, but not fast enough to be of practical importance in photovoltaic devices.

Download Full-text

Effect of the double grading on the internal electric field and on the carrier collection in CIGS solar cells

Solar Energy Materials and Solar Cells ◽

10.1016/j.solmat.2020.110948 ◽

2021 ◽

Vol 223 ◽

pp. 110948

Author(s):

Alban Lafuente-Sampietro ◽

Katsuhisa Yoshida ◽

Shenghao Wang ◽

Shogo Ishizuka ◽

Hajime Shibata ◽

...

Keyword(s):

Solar Cells ◽

Electric Field ◽

Internal Electric Field ◽

Carrier Collection ◽

Cigs Solar Cells

Download Full-text

Design of Grating Al2O3 Passivation Structure Optimized for High-Efficiency Cu(In,Ga)Se2 Solar Cells

Sensors ◽

10.3390/s21144849 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4849

Author(s):

Chan Hyeon Park ◽

Jun Yong Kim ◽

Shi-Joon Sung ◽

Dae-Hwan Kim ◽

Yun Seon Do

Keyword(s):

Solar Cells ◽

High Efficiency ◽

Surface Passivation ◽

Rear Surface ◽

Maximum Efficiency ◽

Structural Factors ◽

Carrier Recombination ◽

Cigs Solar Cells ◽

Effective Carrier ◽

Opening Width

In this paper, we propose an optimized structure of thin Cu(In,Ga)Se2 (CIGS) solar cells with a grating aluminum oxide (Al2O3) passivation layer (GAPL) providing nano-sized contact openings in order to improve power conversion efficiency using optoelectrical simulations. Al2O3 is used as a rear surface passivation material to reduce carrier recombination and improve reflectivity at a rear surface for high efficiency in thin CIGS solar cells. To realize high efficiency for thin CIGS solar cells, the optimized structure was designed by manipulating two structural factors: the contact opening width (COW) and the pitch of the GAPL. Compared with an unpassivated thin CIGS solar cell, the efficiency was improved up to 20.38% when the pitch of the GAPL was 7.5–12.5 μm. Furthermore, the efficiency was improved as the COW of the GAPL was decreased. The maximum efficiency value occurred when the COW was 100 nm because of the effective carrier recombination inhibition and high reflectivity of the Al2O3 insulator passivation with local contacts. These results indicate that the designed structure has optimized structural points for high-efficiency thin CIGS solar cells. Therefore, the photovoltaic (PV) generator and sensor designers can achieve the higher performance of photosensitive thin CIGS solar cells by considering these results.

Download Full-text