An extensive review has just come out on the topic of chemically modified black phosphorus and transition metal dichalcogenides. The authors cover both intentional and unintentional modifications to the materials and, of course, the electronic consequences.
Ref: Ryder, Wood, Wells, and Hersam, “Chemically Tailoring Semiconducting Two-Dimensional Transition Metal Dichalcogenides and Black Phosphorus”, ACS Nano xxxx, 2016, DOI: 10.1021/acsnano.6b01091. Also at arXiv:1603.08544.