Homojunction Sb2Se3 Solar Cell

Antimony selenide (Sb ₂ Se ₃ ) has emerged as a promising thin-film photovoltaic absorber due to its ideal bandgap (1.1-1.3 eV), high absorption coefficient (>10⁵ cm ^- ¹), and environmentally benign composition. However, Sb ₂ Se ₃ solar cells (SSCs) often suffer from significant open-circuit voltage ( V _OC ) losses, attributed to weak built-in fields and severe non-radiative recombination at interfaces and the absorber layer. Here, we demonstrate a composition‑driven carrier polarity control strategy to form an n-type/p-type Sb ₂ Se ₃ homojunction. By precisely tuning the chemical potentials of Se and Sb, we reversibly modulate the conductivity type, achieving carrier densities exceeding 10 ¹⁴  cm ^- ³ for the n- and p-type states, with Hall coefficients ranging from −3.14×10 ^- ² m³ C ^- ¹ (n-type) and +9.51×10 ^- ² m³ C ^- ¹ (p-type). More importantly, we incorporate a homojunction structure into the planar SSC, which simultaneously enhances the built-in electric field and passivates deep-level defects. These synergistic effects promote carrier separation, reduce non-radiative recombination, and accelerate carrier extraction. As a result, the study demonstrates a record power conversion efficiency of 10.15% for thermally evaporated Sb ₂ Se ₃ devices, along with the lowest open-circuit voltage deficit (0.459 V) among all reported SSCs. This work not only establishes a new efficiency benchmark for Sb ₂ Se ₃ solar cells but also offers a universal approach for defect management and junction design in emerging chalcogenide photovoltaics.