Facile dissolution of selenium and tellurium in a thiol–amine solvent mixture under ambient conditions

Abstract

Despite their extremely low solubility in most solvents, hexagonal grey selenium and tellurium are shown to be remarkably soluble in binary mixtures of thiols and ethylenediamine (en) at room temperature and ambient pressure. A 1 : 4 vol/vol mixture of ethanethiol (EtSH) and en gave saturated solutions of 38 and 9.3 wt% for grey selenium and tellurium, respectively. Crystalline and phase-pure chalcogen is easily recovered from solution by drying and mild heat treatment at 250 °C (for selenium) or evaporation at room temperature (for tellurium). To demonstrate utility for these dissolved chalcogens, it was shown that elemental antimony readily reacts with the dissolved selenium to give a stable, solution processable Sb–Se precursor solution. In the same way, elemental tin reacts with the dissolved tellurium to generate a Sn–Te precursor solution. Upon solution deposition and heat treatment to 250 °C, these precursor solutions yielded crystalline Sb₂Se₃ and SnTe.