Ultrahigh-resolution full-color perovskite nanocrystal patterning for ultrathin skin-attachable displays

Abstract

High-definition red/green/blue (RGB) pixels and deformable form factors are essential for the next-generation advanced displays. Here, we present ultrahigh-resolution full-color perovskite nanocrystal (PeNC) patterning for ultrathin wearable displays. Double-layer transfer printing of the PeNC and organic charge transport layers is developed, which prevents internal cracking of the PeNC film during the transfer printing process. This results in RGB pixelated PeNC patterns of 2550 pixels per inch (PPI) and monochromic patterns of 33,000 line pairs per inch with 100% transfer yield. The perovskite light-emitting diodes (PeLEDs) with transfer-printed active layers exhibit outstanding electroluminescence characteristics with remarkable external quantum efficiencies (15.3, 14.8, and 2.5% for red, green, and blue, respectively), which are high compared to the printed PeLEDs reported to date. Furthermore, double-layer transfer printing enables the fabrication of ultrathin multicolor PeLEDs that can operate on curvilinear surfaces, including human skin, under various mechanical deformations. These results highlight that PeLEDs are promising for high-definition full-color wearable displays.

Nanomaterial-Based Synaptic Optoelectronic Devices for In-Sensor Preprocessing of Image Data

“…Halide perovskites have been the most highlighted nanomaterials for developing optoelectronic devices because of their high photoabsorption coefficient, excellent exciton generation efficiency, , long carrier lifetime, and long diffusion length (Figure a). , Furthermore, the halide perovskite provides tunability of the optical and electrical characteristics through the modulation of the composition . It has the general formula ABX 3 , where A is a large cation (e.g., MA + = CH 3 NH 3 + , FA + = CH 3 (NH 2 ) 2 + , and Cs + ); B is a divalent transition metal (e.g., Pb 2+ , Sn 2+ , and Cu 2+ ); and X is a halide anion (e.g., Cl – , Br – , and I – ) .…”

“…Halide perovskites have been the most highlighted nanomaterials for developing optoelectronic devices because of their high photoabsorption coefficient, 99 excellent exciton generation efficiency, 100 , 101 long carrier lifetime, 102 and long diffusion length ( Figure 5 a). 103 , 104 Furthermore, the halide perovskite provides tunability of the optical and electrical characteristics through the modulation of the composition.…”

NondemandingIn SituEncapsulation Route to Ultrastable Perovskite Nanocrystals for White Light-Emitting Diodes

“…), upon which PNC-based devices with intriguing attributes were dependent, such as quantum optics, 16 pixelated LEDs, 17 laserdriven projection display, 18 and ultrathin wearable displays. 19 In stark contrast to conventional semiconducting quantum dots with covalent bonding and rigid crystal structure (e.g., CdSe), the structure of PNCs was inherently soft formed by ionic chemical bonding, which rendered the intriguing photophysical phenomenon that was seldomly observed in other types of NCs, including single-photon emission, 16 superfluorescence, 20 and large two-photon absorption cross section. 21 Unfortunately, the low structural integrity of CsPbX 3 NCs exposed to external stimuli (i.e., polar molecules, prolonged light illumination, heat, etc.)…”

“…Predicated on these two versatile methods, a great deal of effort was dedicated to the controlled synthesis of PNCs with distinctive morphologies (i.e., spheroid, star-shaped nanocube, nanorod, , nanowire, , nanosheet, heterostructure, core/shell, , etc. ), upon which PNC-based devices with intriguing attributes were dependent, such as quantum optics, pixelated LEDs, laser-driven projection display, and ultrathin wearable displays . In stark contrast to conventional semiconducting quantum dots with covalent bonding and rigid crystal structure (e.g., CdSe), the structure of PNCs was inherently soft formed by ionic chemical bonding, which rendered the intriguing photophysical phenomenon that was seldomly observed in other types of NCs, including single-photon emission, superfluorescence, and large two-photon absorption cross section …”

Surface-Energy-Mediated Interfacial Adhesion for Mechanically Robust Ultraflexible Organic Photovoltaics

“…Interfacial adhesion contributes to the device’s mechanical stability because it strongly affects the responses of thin films to strain. , In weakly adhered films, strain tends to be localized at defects and thin areas, causing premature cracking. − For flexible OPVs, wherein the constituent layers exhibit large elasticity mismatch, cracks and their propagation along the weakest interface are likely to occur. − Therefore, the mechanical stability of multilayered flexible OPVs can be compromised by weak interfacial adhesion. − The three main approaches available to strengthen interfaces are as follows: (1) Using adhesive materials as functional layers . For instance, poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) behaves as an adhesion promotor that uniformly delocalizes the strain and mitigates cracking.…”