We observe that in order to reach greater than 80% trapping (or the minimum experimental QE from NPL to QD), the diffusion constant of the exciton can be conservatively estimated to be between 1- 10 cm 2 /s (Figure ). The trapped exciton population percentage has a non-zero minimum that depends on the average number of traps per NPL-because they are placed randomly this represents the excitons that are immediately quenched by being placed within the radius of the trap during initialization of the walk.