POS5-0782
Geometry-Engineered Bidentate Phosphines for Effective Surface Passivation and High-Performance CsPbI₃ Quantum-Dot Photodetectors
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Byeongchan Park (POSTECH)
Co-Author(s)
Abstract
Surface halide vacancies in lead halide perovskite quantum dots generate trap states that accelerate nonradiative recombination and limit optoelectronic device performance. Here, we examine how the molecular geometry of bidentate phosphine ligands influences their coordination with CsPbI₃ quantum-dot surfaces. Two ligands with different phosphorus–phosphorus separations, DPPM and DPPP, were systematically compared. Because the P–P spacing of DPPP closely matches the separation between neighboring vacancy sites in the CsPbI₃ lattice, DPPP coordinates more strongly with undercoordinated Pb²⁺ ions and passivates surface defects more effectively than DPPM. Consequently, DPPP-treated films exhibit higher photoluminescence quantum yield, reduced trap density, improved film uniformity, and enhanced phase stability. Photodiodes incorporating these films show increased responsivity together with suppressed dark current and noise, achieving a specific detectivity of 5.67 × 10¹² Jones. These results establish ligand–lattice geometric compatibility as a useful molecular design principle for high-performance perovskite quantum-dot optoelectronics.
