Spin-coated fluorinated PbS QD superlattice thin film with high hole mobility. Issue 20 (14th May 2020)

• Record Type: Journal Article
• Authors: Xia, Pan; Davies, Daniel W.; Patel, Bijal B.; Qin, Maotong; Liang, Zhiming; Graham, Kenneth R.; Diao, Ying; Tang, Ming Lee
• Is Part Of: Nanoscale. Volume 12:Issue 20(2020)
• Page Start: 11174
• Page End: 11181
• Publication Date: 2020-05-14
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr02299c
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Thin films of PbS quantum dots with short fully fluorinated trifluoromethylthiolate ligands (⊖SCF3 ) were spin-coated. TEM and GISAXS indicated a cubic superlattice. Thin film transistor hole mobilities as high as 0.085 cm 2 V −1 s −1 were obtained. Abstract : Motivated by the oleophobic and electron-withdrawing nature of perfluorocarbons, we explore the effect of a trifluoromethyl coating on lead sulfide quantum dots (PbS QDs) in thin film transistor (TFT) geometry. The low surface energy conferred by the oleophobic perfluorocarbons creates QDs packed in a primitive cubic lattice with long range order, as confirmed by grazing incidence small angle X-ray scattering (GISAXS) and transmission electron microscopy (TEM). Hole mobilities as high as 0.085 cm 2 V −1 s −1 were measured in the TFTs. No electron transport was observed. This suggests that the electron-withdrawing nature of the trifluoromethyl ligand is eclipsed by the excess holes present in the PbS QDs that likely stem from cation vacancies induced by the thiol group.