Boosting Carrier Mobility in 2D Layered Perovskites for High-Performance UV Photodetector

2D hybrid perovskites have attracted great interest due to their promising potential in photodetectors. The phase structure, dielectric, and excitonic properties in 2D perovskites play a pivotal role in the performance of the corresponding optoelectronic device. Here a lattice anchoring method is demonstrated to boost carrier mobility in 2D perovskites by tailoring large organic spacer cation layers. By tuning the electron-withdrawing halogens at the 4-position of the phenyl group in the widely investigated component C₆H₅CH₂NH₃ ⁺ (PMA⁺), it is found that the exciton binding energy of 2D perovskites can be reduced by improving the dielectric constant of organic layers. It is revealed that the carrier mobility is increased by 1.5-fold in the F-PMA₂PbCl₄ perovskite. Meanwhile, the lattice stability is improved together with the high material hardness by reducing the distortion of inorganic sheets. The vertically structured UV photodetector with F-PMA₂PbCl₄ perovskite layer achieves a high detectivity of 1.89 × 10¹⁴ Jones. The work opens a new class method for improving the performance of 2D perovskite-based devices and paves the way to high responsivity and sensitivity.