Bandgap engineering of Cu2CdxZn1-xSnS4 alloy for photovoltaic applications: A complementary experimental and first-principles study

Bandgap engineering of Cu2CdxZn1-xSnS4 alloy for photovoltaic applications: A complementary experimental and first-principles study

Bandgap engineering of Cu2CdxZn1-xSnS4 alloy for photovoltaic applications: A complementary experimental and first-principles study
Z.-Y. Xiao, Y.-F. Li, B. Yao, R. Deng, Z.-H. Ding, T. Wu, G. Yang, C.-R. Li, Z.-Y. Dong, L. Liu, L.-G. Zhang, H.-F. Zhao
Journal of Applied Physics, Volume 114, Issue 18, Article number 183506, (2013)
Z.-Y. Xiao, Y.-F. Li, B. Yao, R. Deng, Z.-H. Ding, T. Wu, G. Yang, C.-R. Li, Z.-Y. Dong, L. Liu, L.-G. Zhang, H.-F. Zhao
Band gap engineering, First-principles calculation, First-principles study, Hall effect measurement, Optical absorption measurement, Photovoltaic applications, Photovoltaic materials, Power conversion efficiencies
2013

We report on bandgap engineering of an emerging photovoltaic material of Cu2CdxZn1-xSnS4 (CCZTS) alloy. CCZTS alloy thin films with different Cd contents and single kesterite phase were fabricated using the sol-gel method. The optical absorption measurements indicate that the bandgap of the kesterite CCZTS alloy can be continuously tuned in a range of 1.55-1.09 eV as Cd content varied from x = 0 to 1. Hall effect measurements suggest that the hole concentration of CCZTS films decreases with increasing Cd content. The CCZTS-based solar cell with x = 0.47 demonstrates a power conversion efficiency of 1.2%. Our first-principles calculations based on the hybrid functional method demonstrate that the bandgap of the kesterite CCZTS alloy decreases monotonically with increasing Cd content, supporting the experimental results. Furthermore, Cu2ZnSnS4/Cu 2CdSnS4 interface has a type-I band-alignment with a small valence-band offset, explaining the narrowing of the bandgap of CCZTS as the Cd content increases. Our results suggest that CCZTS alloy is a potentially suitable material to fabricate high-efficiency multi-junction tandem solar cells with different bandgap-tailored absorption layers.




10.1063/1.4829457

00218979