Enhanced Room Temperature Carrier Mobility in 2D Halide Perovskite [(BA) 2 PbI 4 ] via Low Voltage Polymer Electrolyte Gated FET

ABSTRACT Two‐dimensional (2D) layered perovskite Butylammonium Lead Iodide [(BA) 2 PbI 4 or BAPI] has become a promising material for optoelectronic applications due to their suitable bandgaps and atomic‐scale thickness. However, limited carrier mobility and inefficient charge transport in individual BAPI films impede their extensive device integration in high‐performance electronic applications. In this work, we employ an electrolyte‐gated field‐effect transistor (EGFET) configuration to enhance charge transport in solution‐processed 2D BAPI films. A polymeric electrolyte (PEO/LiClO 4 ) is used as gate dielectric, forming an electric double layer (EDL) at the electrolyte/BAPI interface. It provides a large specific gate capacitance enabling efficient carrier accumulation at low gate voltages. The low‐temperature (<150°C) solution‐processed BAPI based devices exhibit saturation mobility (µ sat ) of 3.80 cm 2 / V . sec and field‐effect mobility reaching up to V ds = 0.5 V .These electrolyte‐gated devices show low threshold voltage . low hysteresis within a small gate bias window ( V g < |5| V ). These results demonstrate a simple, effective strategy for improving charge transport in 2D halide perovskites.