Pure Formamidinium-Based Perovskite Light-Emitting Diodes with High Efficiency and Low Driving Voltage

A formamidinium (FA)-based perovskite showns superior optoelectronic properties including better stability than methylammonium-based counterparts. Pure FA-perovskite-based light-emitting diodes (LEDs) with high efficiency are reported. Interestingly, the LED clearly shows a subbandgap emission at 1.7 V (bandgap 2.3 eV). This important discovery provides further insights of the charge transport mechanism in perovskitebased optoelectronic devices.