  Low-dimensional transition metal dichalcogenide, TMDC, materials are
heralding a new era in optoelectronics and valleytronics owing to their unique
properties. Photo-induced dynamics in these systems has mostly been studied
from the perspective of individual quasi-particles, including excitons,
bi-excitons or, even, trions. Their formation, evolution and decay. The role of
multi-body and exciton dynamics, the associated collective behaviour,
condensation and inter-excitonic interactions remain intriguing and seek
attention, especially in room-temperature scenarios which are relevant for
device applications. In this work we evidence the formation and decay of an
unexpected electron-hole quantum liquid phase at room-temperature on ultrafast
picosecond timescales in multi-layer MoS2 nanoparticles through femtosecond
broadband transient absorption spectroscopy. Our studies reveal the complete
dynamical picture: the initial electron-hole plasma, EHP, condenses into an
quantum electron-hole liquid, EHL, phase which typically lasts as long as 10
ps, revealing its robustness, whereafter the system decays through phonons.
