Tin(IV) Methylselenolate as a Low Temperature SnSe Precursor and Conductive “Glue” Between Colloidal Nanocrystals

Abstract

We report the synthesis of a soluble precursor that transforms into crystalline SnSe at 200 °C. This transformation temperature is significantly lower than the 270–350 °C range of previously reported tin selenide precursors. This precursor is synthesized by reacting tin with dimethyl diselenide and we identify the precursor as tin(IV) methylselenolate using a combination of mass spectrometry, Raman spectroscopy, and nuclear magnetic resonance spectroscopy. We then chemically treat PbSe colloidal nanocrystals with this precursor and subject them to mild annealing. We characterize the chemical and structural changes during this processing using infrared spectroscopy, aberration‐corrected scanning transmission electron microscopy, and X‐ray photoelectron spectroscopy. These characterization studies indicate the successful formation of a SnSe‐like material that fills the interstitial space between the PbSe nanocrystal cores. We find that the electrical conductivity of these nanocrystal films is comparable to other excellent treatments used to improve charge transport. This excellent charge transport demonstrates the utility of tin(IV) methylselenolate as a conductive “glue” between nanocrystals.

A selenium-based “alkahest”: reactive dissolutions of metals and metal compounds with n-alkylammonium polyselenide solutions

“…This type of processing is limited to certain metal selenides that can dissolve in presence of hydrazine and selenium and some examples of reactive dissolutions of metals with organic diselenides. 22,38 In this work, we present n-alkylammonium polyselenide solutions as a versatile, selenium-based reactive solvent system. These n-alkylammonium polyselenides ((RNH 3 ) 2 Se x ) are simple to synthesize and can dissolve numerous pure metals, metal selenides, metal oxides, and metal salts through the formation of soluble metal polyselenides.…”

“…This type of processing is limited to certain metal selenides that can dissolve in presence of hydrazine and selenium and some examples of reactive dissolutions of metals with organic diselenides. 22,38…”