Hi Yasmin, I guess you didn't filtrate your solutions. It's highly likely that the count rate and correlation functions were affected by dust particles resulting to the appearance of a micron size peak (1000-3000 nm) that is nothing else but artefact. The most interesting information is a small peak located at 50-100 nm range. Try converting the distribution functions from intensity-weighted to volume and number-weighted distributions. Than might give you some better clues about your systems.
Read this review for more information on correct DLS measurement:
Article Dynamic light scattering and transmission electron microscop...