TY - JOUR
T1 - A CZTSe solar cell with 8.2% power conversion efficiency fabricated using electrodeposited Cu/Sn/Zn precursor and a three-step selenization process at low Se pressure
AU - Yao, Liyong
AU - Ao, Jianping
AU - Jeng, Ming Jer
AU - Bi, Jinlian
AU - Gao, Shoushuai
AU - Sun, Guozhong
AU - He, Qing
AU - Zhou, Zhiqiang
AU - Sun, Yun
AU - Chang, Liann Be
N1 - Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - In preparing Cu2ZnSnSe4 (CZTSe) thin films, selenization at high Se pressure is likely to form a thick molybdenum diselenide (MoSe2) layer. An excessively thick MoSe2 layer degrades the performance of CZTSe solar cells. Annealing under low Se pressure has been suggested to prevent the formation of such a thick MoSe2 layer. However, the potential loss of Sn metal from CZTSe thin films at low Se pressure or high temperature raises the additional difficulty of controlling the compositions and phases of the films. Carefully controlling these selenization parameters to yield high-quality CZTSe thin films is important. This study investigates the loss of Sn and the formation of molybdenum diselenide in CZTSe thin films at low Se pressure. Three-step selenization at low Se pressure is performed on an electrodeposited Cu/Sn/Zn precursor to prepare high-quality CZTSe thin films. In the first step, rapid thermal annealing with a substrate temperature of 500 °C and a low Se vapor pressure of 4.6 Pa was performed to reduce the loss of Sn and the thickness of the MoSe2 layer, and thus to obtain a Cu-poor and Zn-rich film. In the second step, a high annealing temperature of 570 °C and an inert gas at high pressure was used to improve elemental diffusion and increase the uniformity of the elemental distribution. In the third step, thermal annealing with a substrate temperature of 500 °C and a low Se vapor pressure of 4.6 Pa was performed to reduce the loss of Sn and the thickness of the MoSe2 layer, and to eliminate the impurity phase of SnSe (which was formed in the second step of annealing) on the surface of the CZTS films. The loss of Sn and the formation of molybdenum diselenide in the CZTSe thin films are negligible when this three-step selenization at low Se pressure is used. When the selenization parameters are properly controlled, CZTSe solar cells with an efficiency of as high as 8.2% can be obtained.
AB - In preparing Cu2ZnSnSe4 (CZTSe) thin films, selenization at high Se pressure is likely to form a thick molybdenum diselenide (MoSe2) layer. An excessively thick MoSe2 layer degrades the performance of CZTSe solar cells. Annealing under low Se pressure has been suggested to prevent the formation of such a thick MoSe2 layer. However, the potential loss of Sn metal from CZTSe thin films at low Se pressure or high temperature raises the additional difficulty of controlling the compositions and phases of the films. Carefully controlling these selenization parameters to yield high-quality CZTSe thin films is important. This study investigates the loss of Sn and the formation of molybdenum diselenide in CZTSe thin films at low Se pressure. Three-step selenization at low Se pressure is performed on an electrodeposited Cu/Sn/Zn precursor to prepare high-quality CZTSe thin films. In the first step, rapid thermal annealing with a substrate temperature of 500 °C and a low Se vapor pressure of 4.6 Pa was performed to reduce the loss of Sn and the thickness of the MoSe2 layer, and thus to obtain a Cu-poor and Zn-rich film. In the second step, a high annealing temperature of 570 °C and an inert gas at high pressure was used to improve elemental diffusion and increase the uniformity of the elemental distribution. In the third step, thermal annealing with a substrate temperature of 500 °C and a low Se vapor pressure of 4.6 Pa was performed to reduce the loss of Sn and the thickness of the MoSe2 layer, and to eliminate the impurity phase of SnSe (which was formed in the second step of annealing) on the surface of the CZTS films. The loss of Sn and the formation of molybdenum diselenide in the CZTSe thin films are negligible when this three-step selenization at low Se pressure is used. When the selenization parameters are properly controlled, CZTSe solar cells with an efficiency of as high as 8.2% can be obtained.
KW - CuZnSnSe (CZTSe) thin films
KW - Low Se vapor pressure
KW - Molybdenum diselenide (MoSe)
KW - The loss of Sn
KW - Three-step selenization
UR - http://www.scopus.com/inward/record.url?scp=84988864336&partnerID=8YFLogxK
U2 - 10.1016/j.solmat.2016.09.028
DO - 10.1016/j.solmat.2016.09.028
M3 - 文章
AN - SCOPUS:84988864336
SN - 0927-0248
VL - 159
SP - 318
EP - 324
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
ER -