Electroluminescence from perovskite LEDs with the structure of Ag/Spiro-OMeTAD/CH3NH3PbI3/TiO2/FTO

Highlights: • The Pe-LEDs based on two-step CH₃NH₃PbI₃ were synthesized. • A dominant near-infrared EL was detected from the Pe-LEDs at room temperature. • The origin and mechanism of the EL were discussed in comparison with PL spectra. • The design of perovskite-based devices will benefit from these achievements. The perovskite light-emitting diodes (Pe-LEDs) with the structure of Ag/Spiro-OMeTAD/CH₃NH₃PbI₃/TiO₂/FTO were synthesized, where the CH₃NH₃PbI₃ perovskite layer was deposited by a two-step spin-coating process. A dominant near-infrared electroluminescence (EL) at 773 nm was detected from the Pe-LEDs under forward bias at room temperature. The origin and mechanism of the EL were discussed in comparison with the photoluminescence (PL) spectra, and it was attributed to the radiative recombination of electrons and holes confined in the CH₃NH₃PbI₃ emissive layer. Moreover, the corresponding energy band diagrams was proposed to illustrate the carrier transport mechanism in the Pe-LED device.