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Perovskite light‐emitting diodes (PeLEDs) have shown great potential for low‐cost display and lighting technologies, and all‐inorganic blue PeLEDs are recognized as a promising substitute for blue fluorescent/phosphorescent organic light‐emitting diodes (OLEDs) owing to their superior color purity and great stability potential. However, confined by the solution fabrication process, depositing multi‐layered white PeLEDs remains a challenge. Here, a newly designed hybrid perovskite/organic tandem white LED (POTWLED), integrated with a bottom blue PeLED unit and a top orange/(orange + red) OLED unit, to prevent damage to the underlying perovskite layer caused by the deposition of the top emitting layers, is reported. To optimize the performance of POTWLEDs, a conductive passivator of 2,8‐bis(diphenylphosphoryl)dibenzo[b,d] thiophene, with a strong surface binding group of P═O, is introduced to passivate perovskite defects, which promotes a maximum external quantum efficiency (EQE) of 17.3% for blue PeLEDs with an emission peak at 488 nm. As a result, based on the optimized blue PeLED units, a maximum EQE of 23.9% with a low color temperature of 2522 K is obtained for POTWLEDs, which is the highest efficiency for perovskite‐based WLEDs, illustrating the great potential of the hybrid tandem device in fabricating high‐performance perovskite‐based WLEDs. [ABSTRACT FROM AUTHOR]

Hybrid white organic light-emitting diodes (WOLEDs) have drawn great attention both for display and solid-state lighting purposes because of the combined advantages of desirable stability of fluorescent dyes and high efficiency of phosphorescent materials. However, in most WOLEDs, obtaining high efficiency often requires complex device structures. Herein, we achieved high-efficiency hybrid WOLEDs using a simple but efficacious structure, which included a non-doped blue emissive layer (EML) to separate the exciton recombination zone from the light emission region. After optimization of the device structure, the WOLEDs showed a maximum power efficiency (PE), current efficiency (CE), and external quantum efficiency (EQE) of 82.3 lm/W, 70.0 cd/A, and 22.2%, respectively. Our results presented here provided a new option for promoting simple-structure hybrid WOLEDs with superior performance. [ABSTRACT FROM AUTHOR]

All-inorganic perovskite light-emitting diodes (AIPeLEDs) have been demonstrated with superior thermal stability than organic analogues, but the high defect density and lattice strain of all-inorganic perovskites commonly result in compromised efficiency and stability of the devices. Herein, a self-assembled molecule, 4-bromobenzoic acid (BBA), is adopted as an additive to modify CsPbBr 3 -based green AIPeLEDs. In particular, the formic acid group (-COOH) of BBA can interact with the uncoordinated Pb dangling bonds, leading to reduced defects and released lattice strain of perovskites, thereby facilitating the formation of all-inorganic perovskite films with a high photoluminescence quantum yield of 54.5 %. As a result, AIPeLEDs with a high maximum current efficiency of 42.4 cd A−1, and an external quantum efficiency of 11.4 % are obtained. Moreover, promoted by the inhibited non-radiative recombination and released lattice stress, the T 50 lifetime (at an initial brightness of 200 cd m−2) is also improved from 2 h for the control PeLEDs to 8 h for the BBA-treated PeLEDs, which further confirms the superiority of BBA in passivating the AIPeLEDs. • A self-assembled molecule (SAM), 4-bromobenzoic acid (BBA), is adopted as an additive to modify all-inorganic perovskite CsPbBr 3 film crystallization properties for the fabrication of green AIPeLEDs. • The interaction between the formic acid group (-COOH) of BBA with the uncoordinated Pb dangling bonds can lead to reduced defects and released lattice strain of perovskites, which promotes a high photoluminescence quantum yield (PLQY) of 54.5 %. • High-performance AIPeLEDs with an external quantum efficiency (EQE) of 11.4 % and a T 50 lifetime (at an initial brightness of 200 cd m−2) of 8 h are obtained. [ABSTRACT FROM AUTHOR]