Abstract
Our objective in this study was to elucidate the influence of the Zn/Sn ratio (ZTR) in the absorber layer on the formation of secondary phases, leakage current pathways, and the thickness of the MoSe2 layer in Cu2ZnSnSe4 (CZTSe) solar cells. Experiment results revealed that under Zn-rich conditions (ZTR ≥1.11), the bottom of the absorber layer contains small quantities of Cu2-XSe and SnSe2 secondary phases. Under Sn-rich conditions (ZTR ≤0.75), large quantities of SnSe, SnSe2, and Cu2SnSe3 secondary phases appeared on the surface of the absorber layer. Conductive atomic force microscopy (C-AFM) revealed that the presence of secondary phases caused leakage current over large areas at the surface of the absorber layer. We determined that Cu2-XSe is involved in leakage current at CZTSe grain boundaries, whereas SnSe2 or Cu2SnSe3 tend to promote leakage current in the grains (or near grain boundaries). A higher ZTR resulted in a thinner MoSe2 layer due to large quantities of Cu and Na at the bottom of Zn-rich ZTR specimens, which promoted the formation of Cu2-xSe and Na2Se phases. These phases competed with the Mo to react with the Se, which decreased the amount of the MoSe2 formed from Se and Mo, resulting in a thinner MoSe2 layer. The highest conversion efficiency (5.2%) was obtained from a Zn-rich specimen (ZTR1.43). In contrast, the Sn-rich specimens (ZTR0.75 and ZTR0.63) presented conversion efficiency of 0%. The influence of ZTR on device performance can be attributed to widespread leakage current due to excessive quantities of SnSe2 and Cu2SnSe3 secondary phases on the surface of the absorber layer. An overly thick MoSe2 layer was also shown to result in excessive series resistance.
| Original language | English |
|---|---|
| Pages (from-to) | 249-257 |
| Number of pages | 9 |
| Journal | Journal of Alloys and Compounds |
| Volume | 743 |
| DOIs | |
| Publication status | Published - 2018 Apr 30 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry
Cite this
}
A comparative investigation of secondary phases and MoSe2 in Cu2ZnSnSe4 solar cells : Effect of Zn/Sn ratio. / Lin, Yi Cheng; Wang, Li Ching; Liu, Kuan Ting; Syu, Ya Ru; Hsu, Hung Ru.
In: Journal of Alloys and Compounds, Vol. 743, 30.04.2018, p. 249-257.Research output: Contribution to journal › Article
TY - JOUR
T1 - A comparative investigation of secondary phases and MoSe2 in Cu2ZnSnSe4 solar cells
T2 - Effect of Zn/Sn ratio
AU - Lin, Yi Cheng
AU - Wang, Li Ching
AU - Liu, Kuan Ting
AU - Syu, Ya Ru
AU - Hsu, Hung Ru
PY - 2018/4/30
Y1 - 2018/4/30
N2 - Our objective in this study was to elucidate the influence of the Zn/Sn ratio (ZTR) in the absorber layer on the formation of secondary phases, leakage current pathways, and the thickness of the MoSe2 layer in Cu2ZnSnSe4 (CZTSe) solar cells. Experiment results revealed that under Zn-rich conditions (ZTR ≥1.11), the bottom of the absorber layer contains small quantities of Cu2-XSe and SnSe2 secondary phases. Under Sn-rich conditions (ZTR ≤0.75), large quantities of SnSe, SnSe2, and Cu2SnSe3 secondary phases appeared on the surface of the absorber layer. Conductive atomic force microscopy (C-AFM) revealed that the presence of secondary phases caused leakage current over large areas at the surface of the absorber layer. We determined that Cu2-XSe is involved in leakage current at CZTSe grain boundaries, whereas SnSe2 or Cu2SnSe3 tend to promote leakage current in the grains (or near grain boundaries). A higher ZTR resulted in a thinner MoSe2 layer due to large quantities of Cu and Na at the bottom of Zn-rich ZTR specimens, which promoted the formation of Cu2-xSe and Na2Se phases. These phases competed with the Mo to react with the Se, which decreased the amount of the MoSe2 formed from Se and Mo, resulting in a thinner MoSe2 layer. The highest conversion efficiency (5.2%) was obtained from a Zn-rich specimen (ZTR1.43). In contrast, the Sn-rich specimens (ZTR0.75 and ZTR0.63) presented conversion efficiency of 0%. The influence of ZTR on device performance can be attributed to widespread leakage current due to excessive quantities of SnSe2 and Cu2SnSe3 secondary phases on the surface of the absorber layer. An overly thick MoSe2 layer was also shown to result in excessive series resistance.
AB - Our objective in this study was to elucidate the influence of the Zn/Sn ratio (ZTR) in the absorber layer on the formation of secondary phases, leakage current pathways, and the thickness of the MoSe2 layer in Cu2ZnSnSe4 (CZTSe) solar cells. Experiment results revealed that under Zn-rich conditions (ZTR ≥1.11), the bottom of the absorber layer contains small quantities of Cu2-XSe and SnSe2 secondary phases. Under Sn-rich conditions (ZTR ≤0.75), large quantities of SnSe, SnSe2, and Cu2SnSe3 secondary phases appeared on the surface of the absorber layer. Conductive atomic force microscopy (C-AFM) revealed that the presence of secondary phases caused leakage current over large areas at the surface of the absorber layer. We determined that Cu2-XSe is involved in leakage current at CZTSe grain boundaries, whereas SnSe2 or Cu2SnSe3 tend to promote leakage current in the grains (or near grain boundaries). A higher ZTR resulted in a thinner MoSe2 layer due to large quantities of Cu and Na at the bottom of Zn-rich ZTR specimens, which promoted the formation of Cu2-xSe and Na2Se phases. These phases competed with the Mo to react with the Se, which decreased the amount of the MoSe2 formed from Se and Mo, resulting in a thinner MoSe2 layer. The highest conversion efficiency (5.2%) was obtained from a Zn-rich specimen (ZTR1.43). In contrast, the Sn-rich specimens (ZTR0.75 and ZTR0.63) presented conversion efficiency of 0%. The influence of ZTR on device performance can be attributed to widespread leakage current due to excessive quantities of SnSe2 and Cu2SnSe3 secondary phases on the surface of the absorber layer. An overly thick MoSe2 layer was also shown to result in excessive series resistance.
UR - http://www.scopus.com/inward/record.url?scp=85041391931&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85041391931&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2018.01.404
DO - 10.1016/j.jallcom.2018.01.404
M3 - Article
AN - SCOPUS:85041391931
VL - 743
SP - 249
EP - 257
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
ER -