Effect of guanidinium chloride in eliminating O2 - electron extraction barrier on a SnO2 surface to enhance the efficiency of perovskite solar cells

Miao Yu; Lijia Chen; Guannan Li; Cunyun Xu; Chuanyao Luo; Meng Wang; Gang Wang; Yanqing Yao; Liping Liao; Sam Zhang; Qunliang Song

doi:10.1039/d0ra01501f

Effect of guanidinium chloride in eliminating O₂ ^- electron extraction barrier on a SnO₂ surface to enhance the efficiency of perovskite solar cells

RSC Adv. 2020 May 21;10(33):19513-19520. doi: 10.1039/d0ra01501f. eCollection 2020 May 20.

Authors

Miao Yu^{1

2}, Lijia Chen³, Guannan Li^{1

2}, Cunyun Xu^{1

2}, Chuanyao Luo^{1

2}, Meng Wang^{1

2}, Gang Wang^{1

2}, Yanqing Yao^{1

2}, Liping Liao^{1

2}, Sam Zhang^{1

2}, Qunliang Song^{1

2}

Affiliations

¹ Institute for Clean Energy and Advanced Materials, School of Materials and Energy, Southwest University Chongqing 400715 P. R. China qlsong@swu.edu.cn.
² Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energy Chongqing 400715 P. R. China.
³ College of Physics and Electronics Engineering, Chongqing Normal University Chongqing 401331 P. R. China.

Abstract

Owing to their low cost, easy fabrication and excellent chemical stability properties, tin dioxide (SnO₂) nanoparticles have been widely employed as an electron transfer material in many high-efficiency perovskite solar cells (PeSCs). However, the adsorbed oxygen species (i.e. O₂ ^-) on the surface of the SnO₂ layer, which are induced by the annealing process under ambient environment, have always been overlooked. In general, the adsorption of oxygen creates an energy barrier at the SnO₂/perovskite interface, impairing the efficiency of PeSCs. In this work, by using guanidinium (GA) chloride to modify the SnO₂ surface, we have successfully improved the power conversion efficiency (PCE) of PeSCs from 15.33% (no GA-modification) to 18.46%, with a maximum fill factor of 80%. The performance enhancement is mainly attributed to the reduced energy barrier at the SnO₂/perovskite interface due to the strong coupling between the GA and the adsorbed oxygen, which has been supported by the FTIR and XPS results. The strategy of reducing the charge extraction barrier by GA modification has been demonstrated to be an efficient approach to improve both the PCE and stability.