Pressure-Enhanced
Vertical Orientation and Compositional
Control of Ruddlesden–Popper Perovskites for Efficient and
Stable Solar Cells and Self-Powered Photodetectors
posted on 2021-12-30, 21:43authored byFei Zhu, Gang Lian, Bingcheng Yu, Teng Zhang, Li Zhang, Haohai Yu, Deliang Cui, Qilong Wang, Huaijin Zhang, Qingbo Meng, Ching-Ping Wong
It
is well-known that two-dimensional Ruddlesden–Popper
(2DRP) perovskite has higher stability than three-dimensional counterparts.
However, fundamental issues still exist in the vertical orientation
and phase composition as well as phase distribution. Here, obvious
control of the film quality of 2DRP PEA2MA4Pb5I16 (n = 5) perovskite is demonstrated
via a thermal-pressed (TP) effect. The crystallinity, morphology,
phase composition, and optoelectronic features unequivocally illustrate
that the TP effect achieves a larger gain size, a smoother surface,
an effectively vertical orientation, a relatively pure phase with
a large n value, a gradient distribution of quantum
wells, and enhanced interlayer interaction. These film and interface
features lead to markedly enhanced charge transport/extraction and
lower trap density. Accordingly, the TP-based perovskite film device
delivers a power conversion efficiency of 15.14%, far higher than
that of the control film device (11.10%) because of significant improvements
in open-circuit voltage and short-circuit current. More importantly,
it also presents excellent hydrophobicity, illumination stability,
and environmental stability. In addition, the 2D perovskite self-powered
photodetector also exhibits high responsivity (0.25 A W–1) and specific detectivity (1.4 × 1012 Jones) at
zero bias.