Dual‐Defect Manipulation Enables Efficient and Spectrally Stable Blue Perovskite Light‐Emitting Diodes

Abstract

Performance of blue solution-processed perovskite light-emitting diodes (LEDs) is limited by availability of blue perovskite materials. Herein, 4-(trifluoromethyl)benzoyl ammonium bromide (4-TMBABr) is used with abundant N-H and C=O groups to passivate the defects and produce highly stable PEA x PA 2-x (CsPbBr 3 ) n-1 PbBr 4 perovskites for blue LED applications. The N-H group in the 4-TMBABr suppresses the Br-ion mismatch through hydrogen bonds (N-H•••Br) and C=O group coordinates the unsaturated lead dangling bonds (C=O:Pb). The effective defect passivation by 4-TMBABr reduces the nonradiative recombination in the perovskite films, hence enhancing its optical performance. In the LED structure, the sodium bis(trifluoromethanesulfonyl)imide (SBTI) modified NiO x films are used to improve the hole transport and to inhibit the fluorescence quenching of the perovskite layer. The dual-defect manipulation strategy is advantageous for producing efficient and spectrally stable blue perovskite LEDs, and the authors demonstrate an LED with maximum luminance of 1094 cd m −2 and external quantum efficiency of 10.3%. This work can inform and underpin future development of blue perovskite LEDs with highly efficient and stabile performance.

Doping Up the Light: A Review of A/B-Site Doping in Metal Halide Perovskite Nanocrystals for Next-Generation LEDs

“…It is difficult to precisely determine the location and distribution of dopants within the host matrix. To address this, researchers employ a combination of techniques such as X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) spectroscopy, high-resolution synchrotron XRD, , and first-principles calculations. These methods are used to investigate the doping mechanisms and accurately identify the positions of dopant ions within the lattice, which are crucial for drawing accurate conclusions.…”

Phosphonic Chloride Assisted Fabrication of Highly Emissive Mixed Halide Perovskite Films in Ambient Air for Blue Light-Emitting Diodes

“…7 Two typical strategies are generally used to produce blue perovskite films and LEDs, i.e., quantum confinement and mixed halide strategy. 8,9 The first one relies on the significant decrease in the size or dimensionality of perovskite crystals to induce a strong quantum confinement effect, 10,11 and the second one is realized by incorporating Cl in Br-based perovskite to increase the bandgap energy. 12−14 Regardless of the differences in these two strategies, a common requirement remains in enhancing the emission of the perovskite films, which is considered as one of the most important factors for improving the performance of blue PeLEDs.…”

“…Metal halide perovskites have attracted extensive interest for light-emitting applications in recent years, and huge progress has been achieved in perovskite light-emitting diodes (PeLEDs). − Blue PeLEDs are drawing particular attention in recent years, and their performance has increased rapidly . Two typical strategies are generally used to produce blue perovskite films and LEDs, i.e., quantum confinement and mixed halide strategy. , The first one relies on the significant decrease in the size or dimensionality of perovskite crystals to induce a strong quantum confinement effect, , and the second one is realized by incorporating Cl in Br-based perovskite to increase the bandgap energy. − Regardless of the differences in these two strategies, a common requirement remains in enhancing the emission of the perovskite films, which is considered as one of the most important factors for improving the performance of blue PeLEDs. ,, …”

High-Performance Blue Perovskite Light-Emitting Diodes Enabled by Synergistic Effect of Additives

“…(2) Organic additives have also been well-employed in blue quasi-2D PeLEDs. − They can modulate the phase easily and concurrently passivate the defects, which can further enhance the efficiency of the blue quasi-2D PeLEDs . However, most organic additives will lead to the sacrifice of conductivity, which will cause low carrier transfer rates and unbalanced carrier transfer. ,, There is, therefore, an urgent need to develop an additive strategy to regulate the phase distribution and enhance carrier transport ability to further improve the performance of blue quasi-2D PeLEDs.…”

“…25 However, most organic additives will lead to the sacrifice of conductivity, which will cause low carrier transfer rates and unbalanced carrier transfer. 16,17,26 There is, therefore, an urgent need to develop an additive strategy to regulate the phase distribution and enhance carrier transport ability to further improve the performance of blue quasi-2D PeLEDs.…”