The development of
future quantum devices such as the maser, i.e.,
the microwave analog of the laser, could be well-served by the exploration
of chemically tunable organic materials. Current iterations of room-temperature
organic solid-state masers are composed of an inert host material
that is doped with a spin-active molecule. In this work, we systematically
modulated the structure of three nitrogen-substituted tetracene derivatives
to augment their photoexcited spin dynamics and then evaluated their
potential as novel maser gain media by optical, computational, and
electronic paramagnetic resonance (EPR) spectroscopy. To facilitate
these investigations, we adopted an organic glass former, 1,3,5-tri(1-naphthyl)benzene
to act as a universal host. These chemical modifications impacted
the rates of intersystem crossing, triplet spin polarization, triplet
decay, and spin–lattice relaxation, leading to significant
consequences on the conditions required to surpass the maser threshold.