Homogeneous Freestanding Luminescent Perovskite Organogel with Superior Water Stability

Abstract

intrinsic optical properties, such as bandgap tunability, long carrier lifetime, high photoluminescence quantum yield, and narrow emission linewidths, [2] render them promising materials for display applications. Using perovskite quantum dots (PQDs) or perovskite nanoparticles (PNPs) including all-inorganic (e.g., CsPbX 3 ) and organic-inorganic (e.g., CH 3 NH 3 PbX 3 ) ones, a broad range of high-performance solar cells, [3] light emitting diodes (LED), [4] lasing, [5,6] waveguides, [7] photodetectors, [8,9] and field effect transistors [10] have been developed in recent years.Accompanied by the excellent performance of PNPs come the undesirable material stability issues. The low formation energy of the material and highly mobile ionic structure with surface traps [11] make perovskites vulnerable to external factors including light, moisture, and temperature. The poor stability has become the major obstacle for the practical application of PQD-based solar cells, LEDs and other devices, whose performance often drop drastically, down to a few hours in ambient environment. [12] Moreover, traditional device fabrication and testing utilize pre-formed PNPs, which require oxygen/moisture-free environment [13] and high temperature [14] for synthesis and postannealing treatment, associated with high energy consumption. Addressing these instability issues, while maintaining the versatile processibility of these perovskite nanomaterials, may offer tremendous opportunities to optoelectronics and energy science. It is highly desirable to achieve in situ and simultaneous formation and protection of PNPs in a one-pot synthesis (where PNPs are formed being protected), which is suitable for large-scale industrial manufacturing with a low energy cost.Recently many strategies have been explored for stabilizing the perovskite materials exposed to various harsh environments. For instance, surface modification including shape-preserving transformation, [15] oligomeric ligand functionalization, [16] and silica matrix encapsulation [4] have been reported to improve the stability, but PNPs in those demonstrations are not fully water resistant. Dense waterproof polymers, such as polystyrene, were Metal-halide perovskites have become appealing materials for optoelectronic devices. While the fast advancing stretchable/wearable devices require stability, flexibility and scalability, current perovskites suffer from ambient-environmental instability and incompatible mechanical properties. Recently perovskite−polymer composites have shown improved in-air stability with the protection of polymers. However, their stability remains unsatisfactory in water or high-humidity environment. These methods also suffer from limited processability with low yield (2D film or beads) and high fabrication cost (high temperature, air/moisture-free conditions), thereby limiting their device integration and broader applications. Herein, by combining facile photo-polymerization with room-temperature in-situ perovskite reprecipitation at low energy cost, a one-step...

Aromatic nonpolar organogels for efficient and stable perovskite green emitters

“…Strategies of incorporating PNCs into polymer networks have been proposed to enhance external stabilities [9][10][11][12][13][14][15] . They are also suitable for preparing solid-state stretchable light-emitting layers, because they can simultaneously provide emitters and matrices.…”

“…Some nanocomposites effectively enhance PLQEs and environmental stabilities, while their rigidity or brittleness is incompatible with stretchable applications [9][10][11] . While elastomeric nanocomposites have also been reported [12][13][14][15] , the PNC is physically mixed and dispersed in those matrices; therefore, their luminescence efficiency or environmental stability has remained insufficient for practical application. Furthermore, their elastic moduli are the range of several megapascals, which is incompatible with recently developed soft ISELDs 4 .…”

Anisotropic Protein Organofibers Encoded With Extraordinary Mechanical Behavior for Cellular Mechanobiology Applications

“…Compared to conventional isotropic organohydrogel systems, the structured ELP-surfactant organofibers show extraordinary mechanical performance. For example, synthesized polymer gel networks have limited tensile strength at the scale of kiloPascal level, [28][29][30][31] and show tenuous modulus property. [32][33][34][35] In our…”

“…Interestingly, organogel-based ELP fibers can be easily spinning from the highly viscous matrices simply drawing via a needle, showing high homogeneity (Figure 1 D, E and Figure S2). [28] ethylene glycol 0.035 / 350-1000 / Cellulose-Gel fiber [29] H 2 O/Glycerol 0.14 0.1 43 0.055 PNP [30] Toluene % 0.25 110 200-900 / Na-alginate-polyacrylamide [31] H 2 O % 0.25 % 0.08 % 700 9 KJ m À2 PNAGA [32] H 2 O % 1 % 0.15 600-1400 1 KJ m À2 P(NaSS-co-MPTC) [33] H 2 O 1-4 0.01-8 % 800 4 KJ m À2 CCP-MCP [33] H 2 O 2.5 0.12 50-500 1.3 KJ m À2 GH-Fiber [34] H 2 O/Glycerol 4.7 16 150 80 KJ m À2 MAPAH [35] H 2 O/DMSO 5.6 AE 0.6 / 1180 AE 100 27 AE 3 Figure 1. Schematic illustration of the assembly and preparation of protein-based organogel fibers.…”

Anisotropic Protein Organofibers Encoded With Extraordinary Mechanical Behavior for Cellular Mechanobiology Applications

“…Compared to conventional isotropic organohydrogel systems, the structured ELP-surfactant organofibers show extraordinary mechanical performance. For example, synthesized polymer gel networks have limited tensile strength at the scale of kiloPascal level, [28][29][30][31] and show tenuous modulus property. [32][33][34][35] In our system, the strength of anisotropic ELP-surfactant organofibers is at least one order of magnitude higher than the isotropic counterparts aforementioned, highlighting their robustness in term of mechanical properties (Table 1).…”