posted on 2021-12-10, 20:34authored byShiuan-Ying Peng, Tzu-Sen Su, Cheng-An Chen, Kai-Wen Chuang, Tzu-Chien Wei, Ying-Chih Liao
A wet
preparation process was developed to prepare vertical gradient
perovskite film (MAPbBr3/MAPbBr3–xIx/MAPbI3) for solar
cells. To avoid mutual dissolution, an MAPbBr3 quantum
dot (QD) ink was directly inkjet printed on a spin-coated MAPbI3 film to create stacked perovskite layers (MAPbBr3 QD/MAPbI3). Intense pulse light (IPL) was used to sinter
the stacked perovskite films. After the IPL sintering process, the
grain size in the stacked layers significantly increased from 16 to
30 nm (MAPbBr3 QD) and from 123 to 538 nm (MAPbI3), respectively. Meanwhile, between the stacked layers, a mixed halide
perovskite (MAPbBr3–xIx) film with a gradient was created.
The IPL-sintered perovskite films remained stable without phase separation
under 15 W/cm2 illimitation for 20 s. The gradient perovskite
films were further assembled as an absorber layer in solar cell and
exhibited a power conversion efficiency (PCE) of 17.06%. Moreover,
the solar cell with vertical gradient showed good moisture stability
and exhibited 80% PCE under relative humidity (RH) = 70% for 500 h.
In summary, this process can create an interfacial gradient layer
between light-absorbing materials and can be further applied to other
material systems.