No abstract

No abstract

No abstract

Oriented polyaniline (PANI) microstructures (e.g., bulks, spheres, flakes, and fibers) were prepared without a template by polymerization at 80 degrees C and crystal growth at 0 degrees C and using a self-assembly method in the presence of hydrochloric acid (HCl) as the dopant. It was found that the shape and size of the resulting PANI microstructures depended on the HCl dosage and aniline concentration. Polyanilinium salt precipitates, as a templete, drive the formation of highly oriented PANI microstructures. The infrared and UV-vis absorption spectra and X-ray diffraction were used to characterize the molecular structures of the PANI microstructures. The results showed that their main structure was identical to those of the emeraldine salt form of PANI.

Metal oxide nanocrystals have been pursued for various applications in photovoltaics as a buffer layer. However, it remains a challenging task to adjust their energy levels to achieve a better match of the donor–acceptor system. Herein, we report the fabrication of graphene quantum dots (GQDs) with bright blue photoluminescence by a top-down strategy based on laser fragmentation with posthydrothermal treatment. The GQDs demonstrate appropriate energy level positions and are used as an intermediate buffer layer between TiO2 and P3HT to form a cascade energy level architecture. The introduction of the GQDs into a bulk heterojunction hybrid solar cell has led to an enhancement of the power conversion efficiency.

No abstract

No abstract

Although organometal halide perovskites have garnered enormous interest in solar cells, scarce attention has been paid to light-emitting devices using formamidinium lead halide perovskite as the emitting layer. Highly luminescent and air-stable formamidinium lead halide perovskite quantum dots using high-melting-point ligands have been synthesized. Through compositional engineering, the emission spectra are readily tunable over the entire visible spectral region of 409− 817 nm. The photoluminescence of FAPbX 3 nanocrystals has narrow emission line widths of 21−34 nm, high quantum yields of up to 88%, and a photoluminescence lifetime of 54.6−68.6 ns for single halide FAPbBr 3 , which could be stable for several months. We have demonstrated the fabrication of highly efficient formamidinium lead halide perovskite quantum dot-based green-light-emitting diodes with a moderately high luminance of 33993 cd m −2 , current efficiency of 20.3 cd A −1 , and moderately high maximum external quantum efficiency of 4.07%.