University of Pennsylvania

Yuming Lai

Cherie Renee Kagan

Ji-Hyuk Choi

David K Kim

Christopher Bruce Murray

Aaron Thomas Fafarman

Soong Ju Oh

Sung-hoon Hong

Sangameshwar Rao Saudari

Weon-Kyu Koh

Methods of preparing a dispersion of colloidal nanocrystals (NCs) for use as NC thin films are disclosed. A dispersion of NCs capped with ligands may be mixed with a solution containing chalcogenocyanate (xCN)-based ligands. The mixture may be separated into a supernatant and a flocculate. The flocculate may be dispersed with a solvent to form a subsequent dispersion of NCs capped with xCN-based ligands.

Methods for the preparation of colloidal nanocrystal dispersion

Methods of forming colloidal nanocrystal (NC)-based thin film devicesare disclosed. The methods include the steps of depositing a dispersion of NCs on a substrate to form a NC thin-film, wherein at least a portion of the NCs is capped with chalcogenocyanate (xCN)-based ligands; and doping the NC thin-film with a metal.

Methods of forming colloidal nanocrystal-based thin film devices

Nanocrystal thin film devices and methods for fabricating nanocrystal thin film devices are disclosed. The nanocrystal thin films are diffused with a dopant such as Indium, Potassium, Tin, etc. to reduce surface states. The thin film devices may be exposed to air during a portion of the fabrication. This enables fabrication of nanocrystal-based devices using a wider range of techniques such as photolithography and photolithographic patterning in an air environment.

Nanocrystal thin film fabrication methods and apparatus

Methods of exchanging ligands to form colloidal nanocrystals (NCs) with chalcogenocyanate (xCN)-based ligands and apparatuses using the same are disclosed. The ligands may be exchanged by assembling NCs into a thin film and immersing the thin film in a solution containing xCN-based ligands. The ligands may also be exchanged by mixing a xCN-based solution with a dispersion of NCs, flocculating the mixture, centrifuging the mixture, discarding the supernatant, adding a solvent to the pellet, and dispersing the solvent and pellet to form dispersed NCs with exchanged xCN-ligands. The NCs with xCN-based ligands may be used to form thin film devices and/or other electronic, optoelectronic, and photonic devices. Devices comprising nanocrystal-based thin films and methods for forming such devices are also disclosed. These devices may be constructed by depositing NCs on to a substrate to form an NC thin film and then doping the thin film by evaporation and thermal diffusion.

Growing community of inventors

Philadelphia, PA, United States of America

Yuming Lai