Organic–inorganic hybrid lead halide perovskite nanocrystals (PeNCs) have received great attention as a light source for perovskite LEDs (PeLEDs) owing to the superior optical properties. However, PeNCs typically use octylamine (OAm) as capping ligands which have insulating properties. Exploring a desirable short alkylamine instead of OAm is required for the improvement of PeLEDs. Here, as one of the strategies to solve this issue, the effects of alkylamine chain length for optical properties of PeNCs and PeLED characteristics are investigated. Pentylamine is an optimal short alkylamine and precipitate luminescent PeNCs with high PLQY values of 90%. Importantly, pentylamine maintains a relatively high PLQY of 48% after spin-coating, due to the durability pentylamine has to ethyl acetate as a washing solvent. PeNCs capped with pentylamine also demonstrate an external quantum efficiency of over 1% with luminance of over 2000 cd cm−2, indicating that pentylamine has the potential to overcome the insulator properties of PeNC thin film.
Polymer
electrolyte fuel cells (PEFC) are expected as next energy
generation systems, and their performance is strongly dependent upon
the polymer electrolyte membrane (PEM). We have suggested a new model
of PEM with a three-dimensional proton conduction passways structure
using the filler method, particularly focused on the functionalization
of filler particles. The polymer surface-functionalized silica nanoparticles
(NPs) with three different particle sizes were prepared by the reversible
addition–fragmentation chain transfer polymerization with particles
(RAFT PwP) method that we developed. Silica NPs coated with an in situ polymerized block copolymer consisted of a proton
conductive polymer and a protective polymer. We confirmed that the
proton conductivity increased and the activation energy decreased
as the core particle size became smaller because of enlarging the
total interface area between each particle and increasing the proton
conduction passways.
We have successfully demonstrated a polymer electrolyte membrane (PEM) composed of core-shell type nanoparticles (NPs) which are silica NPs coated with poly(acrylic acid)-b-polystyrene (PAA-b-PS). In this work, for further improvement of proton conductive performance, we focus on the relationship between the coating amount of PAA and proton conduction performance. The PAA coating amount can be facilely controlled by changing the polymerization conditions. With the optimized PAA coating amount, the proton conductivity shows 9.2 × 10 −4 S cm −1 at 60 °C and 98% relative humidity with low activation energy (E a = 0.33 eV). In addition, with coating PS on
We
have developed a polymer electrolyte membrane (PEM) material
using polymer-coated silica nanoparticles (NPs) by the reversible
addition-fragmentation chain-transfer polymerization with particles
(RAFT PwP) method. In this paper, we controlled the number density
of surface silanol groups on the silica NPs that not only maintain
the structure of the surface adsorbed polymers by RAFT PwP but also
form fast proton-conducting interface to study the silanol density
effect on proton conductivity. The number of surface silanol groups
was successfully increased by NaOH surface treatment and decreased
by heat treatment. Then, we clarified that silanol-rich silica NPs
with a polyacrylic acid and polystyrene block copolymer (PAA-b-PS) applied by RAFT PwP exhibit larger proton conductivity.
This result implies that hydrophilicity of the filler is one of the
important factors in the design of filler-functionalized PEM with
high proton conductivity.
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