No abstract

A novel fluorinated organic–inorganic (O–I) hybrid sol—gel based material, named FAGPTi, is successfully synthesized and applied as a gate dielectric in flexible organic thin‐film transistors (OTFTs). The previously reported three‐arm‐shaped alkoxysilane‐functionalized amphiphilic polymer yields a stable O–I hybrid material consisting of uniformly dispersed nanoparticles in the sol‐state. Here, a fluorinated precursor is introduced into the system, making it possible to realize more stable spherical composites. This results in long‐term colloidal stability (≈1.5 years) because composite growth is strongly inhibited by the presence of fluorine groups with intrinsically strong repulsive forces. Additionally, the FAGPTi film is easily deposited via thermally annealed sol–gel reactions; the films can be successfully fabricated through the printing method, and exhibit excellent flexibility and enhanced insulating properties compared to existing materials. OTFTs with FAGPTi layers show highly stable driving characteristics under severe bending conditions (1.9% strain). Integrated logic devices are also successfully operated with these OTFTs. Additionally, it can facilely be applied to amorphous indium‐gallium‐zinc‐oxide (a‐IGZO) TFT devices other than OTFT. Therefore, this synthetic strategy can provide useful insights into the production of functional O–I hybrid materials, enabling the efficient fabrication of electronic materials and devices exhibiting these properties.

bandgap and low-cost fabrication. Methylammonium (MA) lead halide perovskites, in particular, have drawn much attention as promising materials for next-generation light-emitting diodes (LEDs). In the past 5 years, the external quantum efficiency (EQE) of light-emitting MA perovskite LEDs has increased from <1% to >20% in green, red, and IR spectral ranges. [1][2][3][4][5] However, strategies to fabricate blueemitting Ruddlesden-Popper perovskites (RPPs) typically require to halide substitutions, which result in unstable mixtures that undergo halide phase segregation, and yielding spectrally unstable blue-emitting LEDs. [6][7][8][9] RPPs are layered, quasi-twodimensional structures whose lattices are sliced by two layers of organic spacer cations bound to the (100)-orientated lead bromide octahedra. Their chemical composition is (L) 2 MA n−1 Pb n X 3n+1 , where L is a spacer cation that separates the layers and induces quantum and dielectric confinement. Quasi-2D perovskites with the spacer cation PEA, (PEA) 2 (MA) n−1 Pb n X 3n+1 , have been demonstrated to Ruddlesden-Popper perovskites (RPPs) feature enhanced stability compared to their bulk counterparts and attract attention for potential applications in light-emitting diodes (LEDs). However, to date, blue-emitting RPPs rely on halide compositional tuning, resulting in spectral shifts due to halide segregation under photo-/electrical-excitation. Here, efficient blue-emitting materials with single-halide RPPs using organic spacer engineering are reported. Experimental and computational results show that the (110)-oriented thin films exhibit larger bandgap and enhanced stability regardless of the choice of spacers, relative to the (100)-oriented RPPs. The correlation between the lattice structures and optoelectronic properties reveals that this new class of RPPs exhibits sky-blue emission at 483 nm with a quantum efficiency of ≈62%. Spearman correlation between the steric size of the spacers and the bandgap is estimated to be 92%, showing that the steric effect is crucial influencers. The protocol and strategy established in this study can be exploited to develop blue perovskite LEDs.

No abstract

No abstract