Measurement of the sodium concentration in CIGS solar cells via laser induced breakdown spectroscopy

Abstract

The control of sodium in CIGS solar cells is critical to achieve high efficiency devices, but to date composition measurement techniques either cannot detect the subone atomic percent levels (for example, x-ray fluorescence (XRF)) or are expensive, time consuming, and destructive (examples include SIMS, XPS/ESCA). We employed an inexpensive, fast, and minimally destructive method to measure the concentration of sodium in CIGS solar cells fabricated at the Hawaii Natural Energy Institute (HNEI). Laser induced breakdown spectroscopy (LIBS) was used to determine the relative concentration of sodium. Two different analysis methods of the LIBS data were explored: the first assumes local thermal equilibrium (LTE) of the plasma and is calibration-free while the second employs comparison of relative peak heights after calibration to determine the concentration. Analysis is presented for solar cells produced on thin titanium foils where sodium fluoride is included in the deposition process to incorporate sodium into the CIGS layer.

Industrial applications of laser-induced breakdown spectroscopy: a review

“…58 An application of LIBS which appears to be very interesting in the eld of the solar cell industry is the analysis of thin lm CuIn 1Àx Ga x Se 2 (CIGS) solar cells. Kowalczyk et al 59 used LIBS for determining the concentration of sodium in CIGS cells. Similarly, Lee et al [60][61][62] studied the absorption layer of CIGS cells, in terms of ablation and spectroscopic characteristics, for a rapid composition analysis of thin lm solar cells.…”

Application of laser-induced breakdown spectroscopy to the analysis of secondary materials in industrial production

“…Steel (Aguilera • et al , 1992;Palanco et al , 1999;Bulajic et al , 2002;LopezMoreno et al , 2005;Boue-Bigne, 2007;Noll et al , 2008). Thin fi lm solar cells (Kowalczyk • et al , 2010;Lee et al , 2012). Waste water Lin • et al , 2009).…”