Pnictogen Precursor Chemistry for Metal-Hydride-Free Selective Synthesis of InP1-xSbx Quantum Dots

III–V semiconductor quantum dots (QDs) are RoHS-compliant materials that feature tunable bandgaps and strong quantum confinement. However, the synthesis of InP₁₋ₓSbₓ QDs (0 ≤ x ≤ 1) has been limited by the reliance on hazardous hydride reductants and restricted precursor chemistry. Here, we report a metal-reductant-free strategy using tris(dimethylamino)phosphine [P(NMe2)3] as both phosphorus source and mild reductant, representing the first such approach for InP₁₋ₓSbₓ QDs. The coordination environment of antimony is found to dictate the product composition: Sb–oleylamine complexes afford phase-pure InSb QDs, whereas Sb–trioctylphosphine (TOP) complexes facilitate the formation of alloyed InP₁₋ₓSbₓ QDs (0 ≤ x < 1). The resulting QDs exhibit sharp excitonic absorption features and band-edge emission in the short-wavelength infrared region. Alloying enables continuous bandgap tuning, thereby bridging the previously unobserved emission gap between InP and InSb QDs. This work establishes a safe, high-yielding, and versatile synthetic route to Sb-based III–V QDs and provides a general design principle for expanding the compositional diversity of colloidal semiconductors.