Surface functionalized electrolyte-gated perovskite transistors with enhanced performance via insulating polymer additive

Perovskite–polymer microstructure engineering enables outstanding performance and improved stability in perovskite-based electronic devices. Here, we report perovskite/insulating polymer composite as engineered semiconductors for the simultaneous enhancement of the carrier mobility and environmental stability of electrolyte-gated field-effect transistors (FETs). To this end, we employed conventional poly(methyl methacrylate) (PMMA) and fluorinated poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) insulating polymers. The structural properties of the fabricated perovskite–polymer semiconductors were tuned by controlling the amount of insulating polymer in the perovskite–polymer composites. The optimized methylammonium lead iodide (MAPbI3) perovskite–PMMA-based FETs with a poly(3-hexylthiophene-2,5-diyl) (P3HT) surface passivation layer exhibited a highly-stable operation with a hole mobility of approximately 20 cm2 V−1 s−1 at ≤ 1.5 V and current on/off ratio of ∼103, which exceeds that of the MAPbI3-P(VDF-HFP)-based FETs under highly humid conditions (relative humidity ≈ 60–70%). This exceptional performance of our devices was attributed to the improved injection properties, increased grain size, and passivation of grain boundaries in the transistor channel coupled with the hydrophobic nature, and resistance of the insulating polymers to humidity. This study provide insights into achieving high-performance and environmentally stable perovskite transistor devices through combined bulk and surface passivation.