Polymerized Hybrid Perovskites with Enhanced Stability, Flexibility, and Lattice Rigidity

Abstract

The intrinsic soft lattice nature of organometal halide perovskites (OHPs) makes them very tolerant to defects and ideal candidates for solution-processed optoelectronic devices. However, the soft lattice results in low stability towards external stresses such as heating and humidity, and induces high density of phonons, causing strong electron-phonon coupling. Here, we report solid-state polymerization of OHPs using unsaturated 4-vinylbenzylammonium as organoammonium cations without damaging perovskite structure and its tolerance to defects. The polymerized perovskites show enhanced stability and flexibility compared to regular three-dimensional and twodimensional perovskites. Furthermore, the polymerized 4-vinylbenzylammonium group improves perovskite lattice rigidity substantially, resulting in reduced electron-phonon coupling and non-radiative recombination rate, and enhanced carrier mobility because of suppressed phonon scattering. We demonstrate efficient polymerized perovskite based light-emitting diodes with an external quantum efficiency of 23.2% and enhanced operation stability.

Ion Migration in Perovskite Light‐Emitting Diodes: Mechanism, Characterizations, and Material and Device Engineering

“…[ 238 ] Moreover, polymerization of 4‐vinylbenzylammonium in the perovskite lattice stabilized lattice structure by reducing ion vibration of the metal‐halide octahedron and increasing lattice rigidity. [ 239 ] Other rigid conjugated moieties, such as 7‐(thiophen‐2‐yl)benzothiadiazol‐4‐yl)‐[2,2′‐bithiophen]‐5‐yl)ethylammonium iodide (BTmI), can prevent ion migration and greatly reduce hysteresis, resulting in improved operation stability of (BTm) 2 SnI 4 ‐based PeLED. [ 240 ]…”

Large‐Area and Efficient Sky‐Blue Perovskite Light‐Emitting Diodes via Blade‐Coating

“…Perovskite light-emitting diodes (PeLEDs), one of the most promising applications for metal halide perovskites, have attracted increasing attention due to their advantages such as tunable emission wavelength, high color purity, high conductivity, and solution processability. [1][2][3][4][5][6][7][8][9][10][11] Benefitting from substantial progress in ligand engineering, [12][13][14] energy transfer enhancement, [15,16] trap passivation, [17][18][19][20][21] light extraction CsPb(Br x Cl 1−x ) 3 is very low in popular solvents, such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), compared to the iodide counterparts. [29] This results in much faster crystallization processes than iodide-based perovskite, and makes the film formation process extremely difficult to control, particularly in mass-production techniques such as blade-coating and inkjet printing.…”

“…Perovskite light‐emitting diodes (PeLEDs), one of the most promising applications for metal halide perovskites, have attracted increasing attention due to their advantages such as tunable emission wavelength, high color purity, high conductivity, and solution processability. [ 1–11 ] Benefitting from substantial progress in ligand engineering, [ 12–14 ] energy transfer enhancement, [ 15,16 ] trap passivation, [ 17–21 ] light extraction improvement, [ 22 ] and carrier injection balance management, [ 23 ] the external quantum efficiency (EQE) of PeLEDs has exceeded 20% in near‐infrared/red and green emission regions. Nevertheless, most high‐performance PeLEDs were fabricated by a spin‐coating method with device areas around few square millimeters.…”

“…Nevertheless, most high‐performance PeLEDs were fabricated by a spin‐coating method with device areas around few square millimeters. [ 14,16,19–21 ]…”

“…Nevertheless, most high-performance PeLEDs were fabricated by a spin-coating method with device areas around few square millimeters. [14,16,[19][20][21] Recently, large-area PeLEDs have attracted growing attentions due to their potential applications in solid-state lighting, and a number of breakthroughs have been made. [24][25][26][27] For example, spin coating was tried to make large-area nearinfrared and green PeLEDs with device areas of 9 cm 2 .…”