TY - JOUR
T1 - Cesium compounds as interface modifiers for stable and efficient perovskite solar cells
AU - Arafat Mahmud, Md
AU - Kumar Elumalai, Naveen
AU - Baishakhi Upama, Mushfika
AU - Wang, Dian
AU - Gonçales, Vinicius R.
AU - Wright, Matthew
AU - Justin Gooding, John
AU - Haque, Faiazul
AU - Xu, Cheng
AU - Uddin, Ashraf
N1 - Funding Information:
The authors gratefully acknowledge the financial support provided by Future Solar Technologies Pty. Ltd. for this research work. Authors V.R.G. and J. J. G. thank ARC for the Australian Laureate Fellowship FL150100060 attributed to Scientia Prof. J. Justin Gooding (School of Chemistry, UNSW-Sydney). The authors would also like to acknowledge the endless support from the staffs of Photovoltaic and Renewable Energy Engineering School, Electron Microscope Unit (EMU) and Solid State and Elemental Analysis Unit under Mark Wainwright Analytical Center, UNSW.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/1
Y1 - 2018/1
N2 - The presented work demonstrates the development of highly stable low temperature processed Cesium compound incorporated ZnO electron transport layer (ETL) for perovskite solar cells (PSCs). Cesium compounds such as CA (cesium acetate) and CC (cesium carbonate) modified ETLs are employed for fabricating highly efficient (PCE: ~ 16.5%) mixed organic cation based MA0.6FA0.4PbI3 PSCs via restricted volume solvent annealing (RVSA) method. Here, CA ETL demonstrates a 50 meV upshift in Fermi level position with respect to CC ETL, contributing to higher n-type conductivity and lower electron injection barrier at the interface. Furthermore, CA ETL also exhibits profound influence on the perovskite microstructure leading to larger grain size and uniform distribution. Cesium acetate incorporated devices exhibit about 82% higher PCE compared to conventional CC devices. In addition to higher photovoltaic performance, CA devices exhibit mitigated photo-current hysteresis phenomena compared to CC devices, owing to suppressed electrode polarization phenomena. Besides, the stability of the CA devices are 400% higher than the conventional CC devices, retaining almost 90% of its initial PCE even after a month-long (30 days) systematic degradation study. The mechanism behind superior performance and stability is investigated and discussed comprehensively.
AB - The presented work demonstrates the development of highly stable low temperature processed Cesium compound incorporated ZnO electron transport layer (ETL) for perovskite solar cells (PSCs). Cesium compounds such as CA (cesium acetate) and CC (cesium carbonate) modified ETLs are employed for fabricating highly efficient (PCE: ~ 16.5%) mixed organic cation based MA0.6FA0.4PbI3 PSCs via restricted volume solvent annealing (RVSA) method. Here, CA ETL demonstrates a 50 meV upshift in Fermi level position with respect to CC ETL, contributing to higher n-type conductivity and lower electron injection barrier at the interface. Furthermore, CA ETL also exhibits profound influence on the perovskite microstructure leading to larger grain size and uniform distribution. Cesium acetate incorporated devices exhibit about 82% higher PCE compared to conventional CC devices. In addition to higher photovoltaic performance, CA devices exhibit mitigated photo-current hysteresis phenomena compared to CC devices, owing to suppressed electrode polarization phenomena. Besides, the stability of the CA devices are 400% higher than the conventional CC devices, retaining almost 90% of its initial PCE even after a month-long (30 days) systematic degradation study. The mechanism behind superior performance and stability is investigated and discussed comprehensively.
KW - Cesium compounds
KW - Electrode polarization
KW - Electron injection barrier
KW - Perovskite solar cell
KW - Trap state passivation
UR - http://www.scopus.com/inward/record.url?scp=85028849792&partnerID=8YFLogxK
U2 - 10.1016/j.solmat.2017.08.032
DO - 10.1016/j.solmat.2017.08.032
M3 - Article
AN - SCOPUS:85028849792
VL - 174
SP - 172
EP - 186
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
SN - 0165-1633
ER -