Degradation Mechanism Due to Water Ingress Effect on the Top Contact of Cu(In,Ga)Se2 Solar Cells

Abstract

The impact of moisture ingress on the surface of copper indium gallium diselenide (CIGS) solar cells was studied. While industry-scale modules are encapsulated in specialized polymers and glass, over time, the glass can break and the encapsulant can degrade. During such conditions, water can potentially degrade the interior layers and decrease performance. The first layer the water will come in contact with is the transparent conductive oxide (TCO) layer. To simulate the impact of this moisture ingress, complete devices were immersed in deionized water. To identify the potential sources of degradation, a common window layer for CIGS devices—a bilayer of intrinsic zinc oxide (i-ZnO) and conductive indium tin oxide (ITO)—was deposited. The thin films were then analyzed both pre and post water soaking. To determine the extent of ingress, dynamic secondary ion mass spectroscopy (SIMS) was performed on completed devices to analyze impurity diffusion (predominantly sodium and potassium) in the devices. The results were compared to device measurements, and indicated a degradation of device efficiency (mostly fill factor, contrary to previous studies), potentially due to a modification of the alkali profile.

Performance Improvement of Hybrid-Perovskite Solar Cells with Double Active Layer Design Using Extensive Simulation

“…ZnO and Spiro-OMeTAD are selected as the ETL and the HTL, respectively, from the earlier works, which resulted in obtaining higher efficiency. The front contact electrode, i.e., ITO is used in CIGS-based SCs, and hence, it validates the feasibility of ITO with CIGS materials. − The working principle of SC (CIGS/CsSnI 3 ) is represented in Figure b. The absorption coefficient (α) is illustrated from SCAPS-1D software where we utilized the term α = A α ( h ν – E g ) 1/2 .…”

In Situ Recrystallization of Co-Evaporated Cu(In,Ga)Se2 Thin Films by Copper Chloride Vapor Treatment towards Solar Cell Applications

“…No significant signal is observed for chlorine even after recrystallization, which seems to indicate that the element does not remain in the films despite enhancing the grains. As shown by SIMS, the reference sample has a deep Ga notch, typical of CIGS films deposited by a three-stage process [14]. As CuCl2 is introduced, the depth of the notch decreases significantly and nearly disappear for the second stage HT, indicating the interdiffusion of Ga due to the treatment.…”

Analysis of Post-Deposition Recrystallization Processing via Indium Bromide of Cu(In,Ga)Se2 Thin Films

“…The bottom layer was deposited at higher Ar pressure (1.06 Pa or 8 mTorr), while the top layer was deposited at a low Ar pressure (0.53 Pa or 4 mTorr), resulting in a tensile/compressive stress dipole. The resulting combined thickness of Mo was about 800 nm [7]. CIGS thin films were then Materials 2021, 14, 3596 2 of 9 grown at a substrate temperature of 350 • C using a single stage co-evaporation process.…”