Experimentally we observe that transfer from NPL to QD results in > 85% quenching. Using a Monte Carlo simulation, we determine a theoretical diffusion constant by modeling an exciton on a NPL with a two-dimensional (2D) random walk (Figure ). This model asserts that the movement of the excitons is diffusive rather than ballistic at room temperature, as is consistent with prior work on exciton transport in 2D materials. In our model, the exciton is allowed one of two outcomes: it will either recombine according to the timescale of the experimental total photoluminescence lifetime (Figure ), or it will undergo energy transfer by reaching a position within a radius of a trap (set to be the exciton Bohr radius in bulk HgTe, 40 nm although this is discussed further in Section S12). In all simulations, the exciton is confined to a square 2D area which can vary but follows a normal distribution centered at 500 nm-the average size of a 3 ML HgTe NPL (Figure ). We estimate the trap density to be about 2 traps/NPL (see prior discussion and Supporting Information S2), and each NPL is given a Poissonian number of traps distributed randomly across the 2D sheet (Figure ).