1 research outputs found
Hydrazine-Free Surface Modification of CZTSe Nanocrystals with All-Inorganic Ligand
The
optoelectronic properties of semiconductor nanoparticles (NPs)
depend sensitively on their surface ligands. However, introducing
certain organic ligands to the solution-synthesized CZTSe NPs unfavorably
suppresses the interaction among those NPs. These organic ligands
prevent the NPs from dissolving in water and create an insulating
barrier for charge transportation, which is the key property for semiconductor
devices. In our study, by adopting Na<sub>2</sub>S to displace the
associated organic ligands on Cu<sub>2</sub>ZnSnSe<sub>4</sub> (CZTSe),
we obtained high solubility NPs in an environmentally friendly polar
solvent as well as excellent charge transport properties. Toxicity
of CZTSe: Na<sub>2</sub>S NPs was determined to be around 10 mg/L.
Because of the inorganic ligand S<sup>2–</sup> around CZTSe
NPs, thin films can be easily fabricated by solution processing out
of benign solvents like water and ethanol. After annealing, a homogeneous
CZTSSe absorbing layer without carbon point defects was obtained.
As the S<sup>2–</sup> effectively facilitates the electronic
coupling in nanocrystal thin films, carrier mobility of the surface-engineered
CZTSe enhances from 4.8 to 8.9 cm<sup>2</sup>/(Vs). This raises the
possibility for engineering chalcogenide materials by controlling
the surface properties during the fabrication process