while the lifetime reduces, thus resulting in a stronger PL.

The long-range transport of IXs is confirmed by the spectral dependence of the PL along the transport channel displayed in Fig. \[Fig1\](c). The PL around 1.53 eV is dominated by the recombination of spatially direct neutral (DXs) and charged (DX$^{\pm}$) exciton complexes associated with the two QWs. This emission extends to distances of up to approximately 150 $\mu$m from the generation point due to the expansion of hot excitons and free carriers created by the pulsed laser [@Ref24]. In contrast, the remote emission near the STE edge only shows the red-shifted PL signal, which is attributed to the recombination of acoustically transported IX packets. The energy of this remote PL is determined (via the QCSE) by the bias applied to the STE. The PL intensities integrated over the transport channel with and without a SAW differ by less than 1%, demonstrating that the SAW transports the excitons introducing negligible losses. Moreover, by calculating the ratio between the integrated PL intensity for IXs at the excitation point in the absence of SAW and at the recombination point for P$_{RF}$=10 dBm (cf. Fig. \[Fig1\](c)), one can estimate the exciton transport efficiency, which 