@article{ref1,
title="Safe and fast synthesis of black phosphorus and its purification",
journal="ACS Omega",
year="2020",
author="Kitada, Shunya and Shimizu, Natsuhiko and Hossain, Md Zakir",
volume="5",
number="20",
pages="11389-11393",
abstract="We report a rapid and safe procedure for the synthesis of black phosphorus (BP) by the chemical transport reaction (CTR) method and a purification procedure for the as-prepared BP. Frequent explosion of glass ampules containing reactants (red P, Sn, and SnI4) during high-temperature annealing in the CTR method is inevitable. We found that any danger from the explosions can be prevented by enclosing the glass ampule in a flange-fitted stainless-steel tube without compromising the yield and the quality of BP. In contrast to prolonged heating at approximately 823 K, the BP crystals can be synthesized by immediately cooling (100 K/h) to 400 K after heating the glass ampule to the desired highest temperature (∼823-873 K) over 2 h. The minimum time required for BP synthesis is estimated to be approximately 5 h. The as-prepared BP predominantly contains Sn and I impurities on the upper layers of the BP flakes. These impurities can be removed by exfoliating the upper layers of the flakes or by combining vacuum annealing at ∼600 K and HCl treatment.<p /> <p>Language: en</p>",
language="en",
issn="2470-1343",
doi="10.1021/acsomega.0c00404",
url="http://dx.doi.org/10.1021/acsomega.0c00404"
}