Oscillatory barrier-assisted Langmuir–Blodgett deposition of large-scale quantum dot monolayers

• Large-scale monolayers of quantum dots with full coverage up to several millimeters have been achieved by incorporating oscillatory barriers in the commonly used Langmuir–Blodgett method.
• By examining dilatational moduli as a function of average particle density, one can obtain an appropriate density and proper timing for depositing desired films.
• Time evolution of dilatational moduli gives a clear indication of the film morphology and its stability.

Depositing continuous, large-scale quantum dot films with low pinhole density is an inevitable but nontrivial step for studying their properties for applications in catalysis, electronic devices, and optoelectronics. This rising interest in high-quality quantum dot films has provided research impetus to improve the deposition technique. We show that by incorporating oscillatory barriers in the commonly used Langmuir–Blodgett method, large-scale monolayers of quantum dots with full coverage up to several millimeters have been achieved. With assistance of perturbation provided by the oscillatory barriers, the film has been shown to relax towards thermal equilibrium, and this physical process has been supported by molecular dynamics simulation. In addition, time evolution of dilatational moduli has been shown to give a clear indication of the film morphology and its stability.

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