Introduction of Multifunctional Triphenylamino Derivatives
at the Perovskite/HTL Interface To Promote Efficiency and Stability
of Perovskite Solar Cells
posted on 2020-02-14, 15:36authored byBaohua Zhao, Xinyu Yan, Teng Zhang, Xiaotong Ma, Chengben Liu, Heyuan Liu, Keyou Yan, Yanli Chen, Xiyou Li
Surface passivation is a widely used approach to promote the efficiency
and stability of perovskite solar cells (PSCs). In the present project,
a series of new organic surface passivation molecules, which contain
the same triphenylamino group with the hole transfer material of PSCs,
have been synthesized. These new passivation molecules are supposed
to have both “carrier transfer” capability and “defect
passivation” potential. We find that, by using N-((4-(N,N,N-triphenyl)phenyl)ethyl)ammonium
bromide (TPA-PEABr) as a surface passivation molecule, the efficiency
of the PSCs can be improved from 16.69 to 18.15%, mainly due to an
increased Voc (1.09 V compared with 1.02 V in control
devices). The increased Voc is due to the reduced
surface defect density and a better alignment for the related energy
levels after introducing the TPA-PEABr molecules. Moreover, the stability
of the PSCs can be significantly improved in TPA-PEABr passivated
devices due to the hydrophobic nature of TPA-PEABr. Our results successfully
demonstrate that passivation of the perovskite surface with a carefully
designed multifunctional small organic molecule should be a useful
approach for more stable PSCs with high efficiency.