Pressure‐Tuning Localized Excitons Toward Enhanced Emission, Photocurrent Enhancement and Piezochromism in Unconventional ACI‐Type 2D Hybrid Perovskites

Simultaneous enhancement of free excitons (FEs) emission and self-trapped excitons (STEs) emission remains greatly challenging because of the radiative pathway competition. Here, a significant fluorescence improvement, associated with the radiative recombination of both FEs and STEs is firstly achieved in an unconventional ACI-type hybrid perovskite, (ACA)(MA)PbI