  Our recent year's studies of the prototypal FeSe and molecule-intercalated
(Li,Fe)OHFeSe superconductor systems are briefly reviewed here, with emphasis
on experimental observations of the link between the superconductivity and
normal-state electronic property in the single crystals and films. These
samples were successfully synthesized by our recently developed soft-chemical
hydrothermal methods, which are also briefly described. Particularly in the
Mn-doped high-Tc (Li,Fe)OHFeSe film, a strong enhancement of the
superconducting critical current density was achieved, which is promising for
practical application of the superconductivity.
