Design of Chemically Stable Organic Perovskite Quantum Dots for Micropatterned Light‐Emitting Diodes through Kinetic Control of a Cross‐Linkable Ligand System

Abstract

Perovskite quantum dot (QD) light‐emitting diodes (PeLEDs) are ideal for next‐generation display applications because of their excellent color purity, high efficiency, and cost‐effective fabrication. However, developing a technology for high‐resolution multicolor patterning of perovskite QDs remains challenging, owing to the chemical instability of these materials. To overcome these issues, in this work, the generation of surface defects is prevented by controlling the ligand‐binding kinetics using a stable ligand system (Stable LS). The crystalline reconstruction of perovskite QDs after addition of the Stable LS results in an ≈18% increase in their photoluminescence quantum yield in solution and it also improves the ambient stability of the perovskite QD solution. Moreover, the perovskite QDs with Stable LS can undergo cross‐linking under UV irradiation. The tightly bridged perovskite QDs effectively prevent moisture‐assisted ligand dissociation in film state due to the increased hydrophobicity and restricted movement of the cross‐linked surface ligands. Thus, the cross‐linked perovskite QD film shows improved chemical/environmental stability without substantial deterioration in optoelectrical properties. As a result, a white electroluminescent device with high resolution (≈1 μm) is successfully fabricated by inkjet printing using green and red perovskite QDs.

Direct Optical Lithography of CsPbX3 Nanocrystals via Photoinduced Ligand Cleavage with Postpatterning Chemical Modification and Electronic Coupling

“…Alternatively, LHP NCs can be photopatterned directly by including a photosensitive component into the LHP NC solution (or LHP NC precursor solution). This can be done by the use of cross-linkable ligands, − embedding the LHP NCs in a monomer matrix that can be photopolymerized, or in situ crystallization of LHP NCs in an oxide/polymer matrix with a pulsed laser. , These approaches typically result in a patterned nanocomposite consisting of LHP NCs dispersed in an insulating matrix, which can be helpful to increase the chemical stability of the LHP NCs. However, this process prevents electrical contact with the NCs, which is crucial for devices such as LEDs and photodetectors.…”

Quantum Dot Self-Assembly Deposition in Physically Confined Microscale Space by Using an Inkjet Printing Technique

“…1−7 In addition, the excellent solution-processing capability of quantum dots is compatible with low-cost micro/nano fabrication technologies for patterning and pixelated applications. 8,9 Inkjet printing, one of the most universal and promising noncontact solutionprocessing digital patterning technologies, 10 has been widely adopted in various applications including microwave metadevices, 11 millimeter-wave modulators, 12 superconducting arrays, 13 micro-supercapacitors, 14 photodetectors, 15,16 solar cells, 17 anticounterfeiting labels, 18 and display. 5,8,9,19 Compared to the traditional vacuum-depositing technique or solution-processing method such as spin coating, inkjet printing is susceptible to coffee-ring patterns and inhomogeneous films, limiting its cutting-edge and high-performance applications.…”

“…8,9 Inkjet printing, one of the most universal and promising noncontact solutionprocessing digital patterning technologies, 10 has been widely adopted in various applications including microwave metadevices, 11 millimeter-wave modulators, 12 superconducting arrays, 13 micro-supercapacitors, 14 photodetectors, 15,16 solar cells, 17 anticounterfeiting labels, 18 and display. 5,8,9,19 Compared to the traditional vacuum-depositing technique or solution-processing method such as spin coating, inkjet printing is susceptible to coffee-ring patterns and inhomogeneous films, limiting its cutting-edge and high-performance applications. 20,21 The evaporation and its accompanying hydrodynamics of microscale droplets are crucial for the eventual morphology of the inkjet-printed film.…”

“…Quantum dots (QDs), owing to their tunable bandgaps, high emission purity, and high fluorescent quantum yield, have been widely utilized in various light-emitting applications, including light-emitting diodes, lasers, displays, and anticounterfeiting labels. − In addition, the excellent solution-processing capability of quantum dots is compatible with low-cost micro/nano fabrication technologies for patterning and pixelated applications. , Inkjet printing, one of the most universal and promising noncontact solution-processing digital patterning technologies, has been widely adopted in various applications including microwave metadevices, millimeter-wave modulators, superconducting arrays, micro-supercapacitors, photodetectors, , solar cells, anticounterfeiting labels, and display. ,,, Compared to the traditional vacuum-depositing technique or solution-processing method such as spin coating, inkjet printing is susceptible to coffee-ring patterns and inhomogeneous films, limiting its cutting-edge and high-performance applications. , The evaporation and its accompanying hydrodynamics of microscale droplets are crucial for the eventual morphology of the inkjet-printed film . Currently, the effects of solvent composition, additives, particle interaction, and substrate modification on droplet evaporation and flow kinetics have been studied to achieve stable inks and desired films. − However, most of these works are confined to two-dimensional flat substrates.…”

Packing-Shape Effects of Optical Properties in Amplified Spontaneous Emission through Dynamics of Orbit–Orbit Polarization Interaction in Hybrid Perovskite Quantum Dots Based on Self-Assembly

“…Organic–inorganic hybrid perovskites have been regarded as highly attractive semiconducting materials with unique solution processing capabilities to demonstrate high photoluminescence (PL) quantum yields, , wide-range tuning on band gaps, − and defect-tolerant transport , toward light-emitting, amplified spontaneous emission (ASE), − and lasing actions. − Recently, enhanced performance of ASE and lasing actions in perovskite quantum dots (QDs) with significantly enhanced photostability has been realized at room temperature through surface ligand engineering , and structure modification of thin films, − indicating fabrication of QD thin films is an important strategy toward developing coherent light sources. Most research centered on colloidal QDs because of their high photoluminescence, tunable wavelength, and narrow emission wavelength. − Essentially, perovskite QDs can be divided into five main types by multiple dimensions: (i) QDs including nanospheres and nanocubes, (ii) nanorods and nanowires, (iii) nanoplates and nanodisks, (iv) supercrystals, and (v) polycrystalline films.…”