Time-dependent CP violation in charmless $b$ decays at LHCb

In the $B$-meson sector, measurements of weak phases not associated with $V_{ub}$ are obtained through time-dependent, flavour-tagged analyses involving \bbbar mixing.In addition to new phases that may enter the mixing loop, charmless $B$ decays have an additional mechanism for unknown particles to induce deviations from the Standard Model expectation due to the sizeable contribution to these decays from penguin topologies.We present the most recent studies of time-dependent $CP$ violation in charmless $B$ decays at the LHCb experiment, including $B_s\rightarrow \phi\phi$, one of the ``golden channels'' for New Physics searches.