The high pixel resolution is emerging as one of the key parameters for the next-generation displays. Despite the development of various quantum dot (QD) patterning techniques, achieving ultrahigh-resolution (>10,000 pixels per inch (PPI)) and high-fidelity QD patterns is still a tough challenge that needs to be addressed urgently. Here, we propose a novel and effective approach of orthogonal electric field-induced template-assisted dielectric electrophoretic deposition to successfully achieve one of the highest pixel resolutions of 23090 (PPI) with a high fidelity of up to 99%. Meanwhile, the proposed strategy is compatible with the preparation of QD pixels based on perovskite CsPbBr₃ and conventional CdSe QDs, exhibiting a wide applicability for QD pixel fabrication. Notably, we further demonstrate the great value of our approach to achieve efficiently electroluminescent QD pixels with a peak external quantum efficiency of 16.5%. Consequently, this work provides a general approach for realizing ultrahigh-resolution and high-fidelity patterns based on various QDs and a novel method for fabricating QD-patterned devices with high performance.

The rare earth La cation is strategically introduced to fundamentally improve CsPbI ₃ phase stability and emission efficiency (near-unity PLQY of 99.3%), prompting great enhancements in the perovskite light-emitting diodes.

Nickel oxide (NiO_x) serves as one of the most promising hole transport materials for perovskite light‐emitting diodes (PeLEDs). However, only moderate PeLED performances have been reported on the pristine NiO_x layer due to insufficient hole injection, interfacial exciton quenching, and poor perovskite quality. Herein, a multifunctional molecule of 3‐mercapto‐1‐propanesulfonate (MPS) is demonstrated to successfully tailor the NiO_x–perovskite heterogenous interface by addressing the above issues. In detail, the large binding energy between mercapto sulfur and nickel induces preferential self‐assembly of the mercapto group on the NiO_x surface, which simultaneously enlarges the NiO_x work function by the formation of interfacial dipole and suppresses the trap‐assisted exciton quenching by the passivation of the oxygen vacancies. Meanwhile, the self‐assembled MPS on NiO_x also favors high‐quality perovskite films with good morphology, high crystallinity, and reduced defects for efficient carrier radiative recombination. As a result, blue PeLEDs show a remarkable efficiency of 10.4%, representing one of the highest efficiencies for NiO_x‐based blue PeLEDs, as well as a very low turn‐on voltage of 2.8 V. Consequently, this work contributes to an efficient approach to tailor the NiO_x–perovskite interface for highly efficient blue PeLEDs.

The direct photopatterning technique provides a straightforward approach for high-resolution quantum dot (QD) patterns for next-generation displays. However, the extensively deteriorated QD optical properties deriving from the changes of the QD surface states and/or surroundings set substantial limitations in obtaining high-quality QD patterns and efficient electroluminescent devices. Here, we propose an ingenious and effective approach by utilizing the photoisomeric transformation from spiropyran to merocyanine for highly emissive QD patterns. We reveal the suppression of non-radiative energy transfer between QDs and the dissociative merocyanine for fast luminescence recovery. We achieve small-sized (0.8 μm), high-resolution (15,800 pixels per inch, PPI), high-fidelity (~100%), multicolor, and elaborated QD pixels, and showcase their good compatibility for CdSe/ZnS and perovskite QD pixel fabrication, as well as on both rigid and flexible substrates. These merits promote highly performing pixelated devices with a large luminance of 35,534 cd m ^{− 2} and a record efficiency of 24.5% at 6350 PPI among the direct photopatterning devices. Furthermore, we verify the wide applicability of the proposed strategy for high-performance pixelated perovskite devices with an efficiency of 13.8% at 1760 PPI. The above results confirm the great value of the proposed approach for high-quality QD patterns and high-performance pixelated devices.