Synthesis of Orthorhombic Black Phosphorus by Chemical Vapor Transport Method

Black phosphorus (BP) with excellent and unique physical and chemical properties has emerged as the most promising semiconductor for energy storage and conversion, micro-nano devices, photo- and electro-catalysis, biomedicine, and so on. It is crucial to synthesize high-quality precursors of orthorhombic BP for realizing the applications of two-dimensional BP and zero-dimensional BP quantum dots. Herein, the effects of mineralizer components and ratios on BP growth were studied by the chemical vapor transport (CVT) method without temperature gradient. The results indicate that orthorhombic BP can be synthesized under some experimental combinations that can be considered viable only when tin (or lead) and iodine coexist together with the appropriate ratio. And the mass ratio ranges of tin and iodine w(Sn/I-2) for BP preparation is wide, and the size of BP crystal obtained at w(Sn/I-2)=0.47 is up to 1.2 cm, of which yield and crystal quality are superior. Combined with the nucleation and growth mechanism of BP, tin and iodine are severely significant for the nucleation and growth of BP, which has been widely accepted. Mineralization effect of iodine is more obvious than that of tin, and sufficient tin contributes to the synthesis of large-size bulk BP crystals without temperature gradient. As a result, w(Sn/I-2)=0.47 is the optimal minera lizer ratia for fabricating orthorhombic BP in this work.

Automated summary

In this study, the effects of mineralizer components and ratios on the growth of black phosphorus were investigated. It was found that orthorhombic black phosphorus can be synthesized when tin and iodine coexist in the appropriate ratio. The optimal mass ratio of tin and iodine for black phosphorus synthesis was determined to be 0.47, which resulted in the formation of high-quality crystals with a size of 1.2 cm.