Work

Intermediate Electronic Coupling via Silane and Germane Bridges in Silicon Quantum Dot–Molecular Hybrid Systems

Year: 2025

Type: article

Abstract: In hybrid Si quantum dot (QD) nanostructures, the bridge connecting the QD and molecular transmitter significantly influences photophysical transformations such as triplet exciton transfer. Here, we present two Si QD:anthracene hybrid systems with molecular silane or germane bridges that, for the first time, enable access to an intermediate QD-anthracene coupling regime. We first describe a new surface functionalization approach that uses methyl radical-mediated dehydrocoupling to install aryldialkylsilanes and germanes onto hydride-terminated Si QD surfaces. Transient absorption spectroscopy and density functional theory calculations show these tetrel bridges mediate QD-anthracene coupling strengths that are intermediate between π-conjugated vinyl and nonconjugated ethyl bridges. We optimize the new hybrids in a triplet upconversion system with 9,10-diphenylanthracene emitters and achieve photon upconversion efficiencies of 6.2% and 5.1% for silane and germane systems, respectively. This work shows that main group element bridges can provide access to QD-transmitter coupling characteristics that are distinct from conventional organic bridges.

Source: Nano Letters

DOI: 10.1021/acs.nanolett.5c00169