Currently,
Spiro-OMeTAD is the most widely used hole transport
material (HTM) in the best-performing perovskite solar cells (PSCs),
resulting from its suitable energy level and facile processing. However,
the intrinsic properties of organic molecules, such as low conductivity
and a nonpolar contact interface, will limit the power conversion
efficiency (PCE) and stability of Spiro-OMeTAD-based PSCs. Chemical
doping could be an effective strategy to ameliorate the performance
of Spiro-OMeTAD, and most of the dopants are designed for controllably
oxidizing Spiro-OMeTAD. In this work, a highly stable metal–organic
framework {[Zn(Hcbob)]·(solvent)}n (Zn-CBOB) with rod topology and Lewis basic sites is assembled and
employed as a dopant for the hole transport layer. It is found that
Zn-CBOB not only controllably oxidizes Spiro-OMeTAD and improves the
conductivity of the HTM but also passivates the surface traps of the
perovskite film by coordinating with Pb2+. The Zn-CBOB-doped
PSCs achieved a remarkable PCE of 20.64%. In addition, the hydrophobicity
of Zn-CBOB can prevent water from destroying the perovskite layer,
which helps elevate the stability of PSCs.