Lead halide perovskites have received much attention as light emitting materials owing to their excellent photoelectronic properties. Despite their high efficiency as light-emitting diodes (LEDs), only a few lead bromide perovskite (APbBr3)-based devices have been developed due to their low stabilities and/or the formation of undesirable phases under ambient condition. This work demonstrates that the addition of a small quantity of guanidinium (GUA) A-site cations into an all-inorganic CsPbBr3 perovskite framework leads to the formation of multidimensional perovskites, with enhanced photoluminescence efficiency due to charge carrier funneling and a pinhole-free surface morphology. All-inorganic 3D CsPbBr3 perovskite films and GUA-incorporated multidimensional quasi-2D films are employed in the fabrication of green LED devices with an inverted structure of glass substrate/indium tin oxide (ITO)/zinc oxide (ZnO)/poly(ethylenimine) (PEI)/perovskite/poly(9-vinylcarbazole) (PVK)/WO3/Al. With the addition of GUA A-site cations, the LEDs based on GUA-incorporated perovskite thin films exhibited much higher brightness of ∼10000 cd m-2 and current efficiency of 9.4 cd A-1 compared to those of Cs-only perovskite thin film LEDs (∼400 cd m-2 and 0.2 Cd A-1, respectively).
Bibliographical noteFunding Information:
This work was supported by the Global Frontier R&D Program of the Center for Multiscale Energy System funded by the National Research Foundation under the Ministry of Science, ICT & Future, Korea (NRF-2012M3A6A7054861).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films