The full blossoming of quantum technologies requires the availability of easy-to-prepare materials where quantum coherences can be effectively initiated, controlled, and exploited, preferably at ambient conditions. Solid-state multilayers of colloidally grown quantum dots (QDs) are highly promising for this task because of the possibility of assembling networks of electronically coupled QDs through the modulation of sizes, inter-dot linkers, and distances. To usefully probe coherence in these materials, the dynamical characterization of their collective quantum mechanically coupled states is needed. Here, we explore by two-dimensional electronic spectroscopy the coherent dynamics of solid-state multilayers of electronically coupled colloidally grown CdSe QDs and complement it by detailed computations. The time evolution of a coherent superposition of states delocalized over more than one QD was captured at ambient conditions. We thus provide important evidence for inter-dot coherences in such solid-state materials, opening up new avenues for the effective application of these materials in quantum technologies.

The absence of hole state filling effects on CdSe nanocrystal TA is shown not to reflect ultrafast hole trapping using sub 10 fs pump–probe spectroscopy.

<div><div><div><p>The full blossoming of quantum technologies requires the availability of easy-to-prepare materials where quantum coherences can be effectively initiated, controlled and exploited, preferably at ambient conditions. Solid-state multilayers of colloidally grown quantum dots (QDs) are highly promising for this task because of the possibility of assembling networks of electronically coupled QDs through the modulation of sizes, inter-dot linkers and distances. To usefully probe coherence in these materials, the dynamical characterization of their collective quantum mechanically coupled states is needed. Here we explore by 2D electronic spectroscopy the coherent dynamics of solid-state multilayers of electronically coupled colloidally grown CdSe QDs and complement it by detailed computations. The time evolution of a coherent superposition of states delocalized over more than one QD was captured at ambient conditions. We thus provide important evidence for inter-dot coherences in such solid-state materials, opening up the effective exploitation of these materials towards quantum technologies.</p></div></div></div>

Signatures of long-lived quantum coherence in light-harvesting complexes invoked a hypothesis that the protein-scaffold vibrations assist energy transfer by bridging energy gaps. To address this hypothesis experimentally in a model system, we compare the coupling strength of donor–acceptor quantum dots (QDs) linked by different organic linkers. The linkers are of the same length, with the same headgroups, but differ in one atom at the center of the chain (carbon, sulfur, or oxygen), which changes the vibrational modes of the molecule. We have studied the energy transfer using these linkers both in dimers of QDs, suspended in solution, and in solid multilayered films. Strongest coupling is achieved when a linker vibration (asymmetric stretch around the central atom in this case) matches the energy gap. The results provide experimental support for the theoretical idea of vibration-assisted transport and noise-assisted quantum transport (NEQT) and have important implications for the artificial design of many-particle nanodevices in which interparticle coupling tuning is required.

<div><div><div><p>The full blossoming of quantum technologies requires the availability of easy-to-prepare materials where quantum coherences can be effectively initiated, controlled and exploited, preferably at ambient conditions. Solid-state multilayers of colloidally grown quantum dots (QDs) are highly promising for this task because of the possibility of assembling networks of electronically coupled QDs through the modulation of sizes, inter-dot linkers and distances. To usefully probe coherence in these materials, the dynamical characterization of their collective quantum mechanically coupled states is needed. Here we explore by 2D electronic spectroscopy the coherent dynamics of solid-state multilayers of electronically coupled colloidally grown CdSe QDs and complement it by detailed computations. The time evolution of a coherent superposition of states delocalized over more than one QD was captured at ambient conditions. We thus provide important evidence for inter-dot coherences in such solid-state materials, opening up the effective exploitation of these materials towards quantum technologies.</p></div></div></div>