Although an efficient charge transport is essential to high-performance perovskite solar cells (PSCs), the serious charge trapping in perovskite films is still a barrier to improve the efficiency of PSCs. To overcome this issue, we efficiently suppress the charge trapping by using polar compound materials to reduce defects and improve the match of work functions in PSCs. 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) is used to form an interfacial dipole layer and triphenylphosphine oxide (TPPO) is employed to passivate defects. The interfacial dipole layer not only reduces the surface work function of electron transport layers (ETLs), but also substitutes organic/Cs cation vacancies. Oxygen atoms in TPPO molecules fill anion vacancies on perovskite crystal surfaces. As a result, the power conversion efficiency (PCE) of the champion PSCs has been improved to 21.1% from 18.7%. The target PSCs retained 98.3% of its initial PCE after 214 days in dry air condition (relative humidity about 22% at 25 °C) due to the reduced defect density in perovskite.
|Journal||Chemical Engineering Journal|
|State||Published - Sep 15 2020|
Bibliographical noteFunding Information:
This work was supported by National Natural Science Foundation of China (Grant Nos. 61874150 , 61421002 and 61574029 ), the Natural Science Foundation of Chongqing ( cstc2019jcyj-msxmX0824 ) and Chongqing Postdoctoral Science Special Foundation (No. Xm2017051 ). This work was also partially supported by University of Kentucky . The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interests.
© 2020 Elsevier B.V.
- Charge transfer
- Perovskite solar cells
- Triphenylphosphine oxide
- Vacancies substitution
ASJC Scopus subject areas
- Chemistry (all)
- Environmental Chemistry
- Chemical Engineering (all)
- Industrial and Manufacturing Engineering