Direct Synthesis of Two-Dimensional SnSe and SnSe₂ through Molecular Scale Preorganization

Area of Science:

• Materials Science
• Inorganic Chemistry
• Nanotechnology

Background:

• Main group metal chalcogenides possess layered structures and tunable electronic properties.
• These materials are of significant interest for optoelectronic applications due to their unique characteristics.
• Developing efficient synthetic routes for two-dimensional (2D) materials is crucial for technological advancement.

Purpose of the Study:

• To synthesize novel molecular precursors for tin selenides.
• To demonstrate the efficient production of 2D tin monoselenide (SnSe) and tin diselenide (SnSe2) via thermolysis.
• To explore microwave-assisted decomposition for synthesizing SnSe2 and SnSSe2- particles.

Main Methods:

• Synthesis of tin selenide precursors using a novel class of seleno-ligands and SnCl4.
• Characterization of molecular precursors using multinuclear magnetic resonance and single-crystal X-ray diffraction.
• Thermolysis and microwave-assisted decomposition of precursors to yield 2D tin chalcogenides.

Main Results:

• Stable tin selenide precursors, including [SnIV(SeC2H4N(Me)C2H4Se)2], [SnIVCl2(SeC2H4N(Me)C2H4Se)], and [SnIV(SC2H4N(Me)C2H4S)(SeC2H4N(Me)C2H4Se)], were successfully synthesized.
• Preorganization of tin-selenium bonds in precursors allowed direct and reproducible synthesis of 2D SnSe and SnSe2 by adjusting pyrolysis temperature.
• Experimental and computational analyses confirmed the synthesis of SnSe2 and SnSSe2- particles, including a selenium-rich SnSSe2- phase from a single precursor.

Conclusions:

• A new class of molecular compounds serves as effective precursors for 2D tin selenides.
• The synthetic strategy offers a controllable and reproducible method for producing SnSe and SnSe2.
• This work advances the synthesis of 2D metal chalcogenides for potential optoelectronic applications.