| 1. |
- Ledinek, Dorothea, et al.
(författare)
-
Thickness and Ga content variations in co-evaporated CIGS solar cells with a flat Ga profile : an electrical characteriyation
- 2014
-
Ingår i: EU PVSEC 2014 Proceedings Papers. - Munchen. ; , s. 1832-1836
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this work an extensive experimental series has been carried out by co-evaporating CIGS layers with varying thickness (0.5, 1.0, 1.5 µm) and varying Ga content (Ga/(Ga+In)=0.15, 0.30, 0.45 and 0.60). In all CIGS layers the Cu concentration has been held constant at Cu/(In+Ga)=0.85. The cells have been characterized with dark and light current voltage measurements, external quantum efficiency measurements and apparent quantum efficiency measurements at negative bias. In agreement with the literature, we observe a distinctively shorter collection length for high Ga concentrations and voltage dependent photo current collection for all cells. Voltage dependent current collection however cannot alone explain our data and the cells need to be described with an illumination dependent diode current or photo current. The generation dependent diode or photo current increase the slope of the light JV curve at negative bias voltage for all solar cells and dominates the slope in cells with 0.5 µm thin absorbers regardless of Ga content. We propose that this behavior is connected to the recombination at the back contact, as it is smaller in the cells with thick absorber layers and since we do not observe the same behavior in back side passivated cells. Keywords: Cu(InGa)Se2, Modelling, Electrical Characterization, Shunting, Ga content, thin absorbers, superposition principle, shifting approximation
|
|
| 2. |
- Szaniawski, Piotr, et al.
(författare)
-
Light-enhanced reverse breakdown in Cu(In,Ga)Se2 solar cells
- 2013
-
Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 535, s. 326-330
-
Tidskriftsartikel (refereegranskat)abstract
- Partial shading of solar modules can subject shaded cells to significant reverse bias, often large enough toforce them into electrical breakdown, possibly resulting in irreversible damage. Therefore, better understandingof reverse current–voltage characteristics might lead to improvements in the design of solar modules. Thefocus of this study is the breakdown behavior of Cu(In,Ga)Se2 (CIGS) cells in darkness and under illumination.Two series of CIGS cells were investigated, with CdS and Zn–Sn–O buffer layers of varying thickness. Electricalbreakdown was found to be highly dependent on the buffer layer. Under blue illumination a remarkable decreasein breakdown voltage was observed for both buffer types. Metastable defects in the buffer/CIGS interfaceregion are tentatively proposed as the source of this effect and tunnelling is suggested as the mainmechanism responsible for breakdowns.
|
|
| 3. |
- Wallin, Erik, et al.
(författare)
-
World record Cu(In,Ga)Se2-based thin-film sub-module with 17.4 % efficiency
- 2012
-
Ingår i: Progress in Photovoltaics. - : John Wiley & Sons. - 1062-7995 .- 1099-159X. ; 20:7, s. 851-854
-
Tidskriftsartikel (refereegranskat)abstract
- We report a new certified world-record efficiency for thin-film Cu(In,Ga)Se2-based photovoltaic sub-modules of 17.4%(aperture area). The record efficiency of the 16 cm2, monolithically integrated, sub-module has been independently confirmedby Fraunhofer ISE. The record device is the result of extensive co-optimization of all processing steps. Duringthe optimization process, strong focus has been put on the scalability of processes to cost-effective mass production, asreflected, for example, in Cu(In,Ga)Se2 deposition time and substrate temperature. Device manufacturing as well as resultsof electrical and material characterization is discussed.
|
|
