[2PS-152]
Lattice-Matched Bidentate Phosphine Ligands for Efficient Defect Passivation and Enhanced Performance in Lead Halide Perovskite Quantum Dots
발표자박병찬 (포항공과대학교)
연구책임자조길원 (포항공과대학교)
Abstract
Halide vacancies on lead halide perovskite (LHP) quantum dots (QDs) impair optoelectronic performance by acting as nonradiative recombination centers and charge traps. While ligand exchange is widely used for surface passivation, the role of intramolecular geometry in multidentate ligands remains unclear. Here, we study how the phosphorus–phosphorus (P–P) distance in two bidentate phosphines, DPPM and DPPP, affects binding to CsPbI₃ QDs and defect passivation. With a lattice-matched P–P spacing, DPPP binds more strongly to undercoordinated Pb²⁺ sites than DPPM, enabling superior passivation. DPPP-treated QDs exhibit reduced trap density, enhanced photoluminescence, and improved film uniformity. Photodiodes based on DPPP show higher responsivity, lower dark current, and reduced noise, reaching a detectivity of 5.67 × 10¹² Jones. These findings demonstrate lattice matching as an effective strategy for optimizing LHP QD devices.