Extracting hot carriers prior to thermalization is a long-standing challenge for surpassing the Shockley-Queisser limit in photovoltaic and optoelectronic devices. Antimony selenide (Sb2Se3), featuring quasi-one-dimensional ribbon-like crystal motifs, has recently emerged as a promising platform for hot-carrier utilization. However, directly resolving the associated ultrafast extraction current remains elusive. Here, by employing polarization-phase-resolved THz emission spectroscopy, we visualized the directed transient hot-electron extraction current at the Sb2Se3/SnO2 interface and identify an ∼1.2 eV pump photon energy threshold by a Fowler-type photoemission model, consistent with the direct band gap of the Sb2Se3. These results position THz emission spectroscopy as a powerful, noncontact metrology for mapping ultrafast and anisotropic hot-carrier dynamics and provide design principles for directional hot-carrier management in Sb2Se3-based energy-conversion devices.
Zhang et al. (2026) studied this question.