PbSe Nanocrystal Network Formation during Pyridine Ligand Displacement

Abstract

Solution-phase pyridine treatment displaced oleic acid capping ligands from the surface of PbSe nanocrystals. During ligand displacement the nanostructure morphology dramatically changed from well-stabilized, individual nanocrystals to form crystallographically connected nanocrystal networks. The network morphology was governed by the diameter of the constituent nanocrystals. Larger nanocrystals showed dipolar alignment but maintained individual nanocrystal character, while smaller nanocrystals crystallographically fused along the <100> axis. Optical studies of nanocrystal thin films showed that pyridine ligand displacement quenches the nanocrystal photoluminescence. Blends of nanocrystals and conjugated polymer showed photoluminescence quenching of the polymer with increasing nanocrystal content. The extent of photoluminescence quenching was only weakly dependent on the nanocrystal size or surface chemistry, suggesting that the interaction between nanocrystal and polymer is mostly in the form of energy transfer rather than charge transfer.

Exceptionally Mild Reactive Stripping of Native Ligands from Nanocrystal Surfaces by Using Meerwein’s Salt

“…For the film treated with NOBF 4 , EDS revealed only Se and background levels of C and O (Supporting Information, Figure S3). This confirmed the oxidizing potential of NOBF 4 when used for PbSe, as the absence of Pb shown by EDS suggested oxidation of Se 2À to Se 0 with concomitant formation of soluble [Pb(MeCN) n ]-(BF 4 ) 2 .…”

Efficient synthesis of PbTe nanoparticle networks

“…For instance, Au networks were prepared from Au particles by hydrothermally detaching surfactants [20], and CdS, ZnS, PbS, CdSe, and CdTe semiconductor networks (aerogels) were fabricated by partial oxidative ligand removal from nanoparticles synthesized in either aqueous or organic solution [21,22]. PbSe nanocrystal networks have also been formed by the displacement of oleic acid ligands with pyridine [23]. In order to circumvent the necessity of removing the template or the synthesis of preformed nanocrystals, we have devised a one-step strategy for the synthesis of nanocrystalline networks using weak ligands.…”

Síntesis de nanocristales de sulfuro de cadmio con recubrimiento mixto 1-Decanotiol/Tiofenol

“…Las disoluciones coloidales de nanocristales o nanopartículas son interesantes para el proceso de fabricación de dispositivos optoelectróni-cos basados en materiales orgánicos, como por ejemplo, en células solares [1], [2], [3], amplificadores de fibra óptica [4] o diodos emisores de luz [5] - [6]. Esto es debido a que la inclusión de los nanocristales modifica las propiedades ópticas de los polímeros conductores, Polivinil Carbanzol (PVK), Poli(3-hexiltiofeno-2,5-diol) (P3HT), Phenyl-C61-Butyric-Acid-Mehtyl Ester (PCBM) [7].…”

“…Se ha comprobado que las propiedades ópticas de las nanopartículas están íntimamente ligadas al tamaño de la misma, ya que el confinamiento cuántico de los portadores de carga, implica un aumento de la energía de la banda prohibida [2].…”