We propose the superfluidity of dipolar excitons in a strip of double-layer transition metal dichalcogenide (TMDC) heterostructures. We show that strain causes a shift in $k$ space between the minimum of the conduction band and the maximum of the valence band. Therefore, we expect that applying strain to this system can cause dark excitons to be created. We numerically calculate the energy spectrum of dark dipolar excitons in strained ${\mathrm{MoS}}_2$, and we calculate their binding energies and effective masses. We show that the dark dipolar excitons in strained TMDC heterostructures form superfluids, and we calculate the sound velocity in the energy spectrum of collective excitations, as well as the mean-field critical temperature for superfluidity. We show that two separate superfluid flows moving in opposite directions will appear in the system, one on each edge of the strip, forming the double layer. We see that the critical temperature for superfluidity increases with the concentration of dark excitons, as well as with the interlayer separation. The fact that dark excitons cannot decay via the simple emission of photons makes it so that the superfluids and condensates formed by them have a much longer lifetime than that formed by bright excitons. We propose a way to experimentally verify the predicted phenomena.

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• Excitons
• Strain
• Superfluid density
• Superfluidity
• Bilayer films
• Transition metal dichalcogenides