Solution Synthesis and Optical Properties of Transition-Metal-Doped Silicon Nanocrystals

Abstract

A new synthetic method was developed to produce a range of transition-metal (Mn, Ni, and Cu) doped silicon nanocrystals (Si NCs). The synthesis produces monodisperse undoped and doped Si NCs with comparable average sizes as shown by transmission electron microscopy (TEM). Dopant composition was confirmed by EDX (energy dispersive X-ray spectroscopy). The optical properties of undoped and doped were compared and contrasted using absorption (steady-state and transient) and photoluminescence spectroscopy. Doped Si NCs demonstrated unique dopant-dependent optical properties compared to undoped Si NCs such as enhanced subgap absorption, and 40 nm shifts in the emission. Transient absorption (TA) measurements showed that photoexcitations in doped Si NCs relaxed via dopant states not present in undoped Si NCs.

Optical Biosensing and Bioimaging With Porous Silicon and Silicon Quantum Dots (Invited Review)

“…This is very encouraging because the tuning of sizes can be achieved fairly easily in practice, which is usually done through colloidal chemistry or other fabrication techniques [92]. Another feature was the strong impact of doping on the optoelectronic properties of silicon nanocrystals, as evidenced from reported cases of both traditional dopants (B and P) and metals (Mn, Ni, Co, Cu) dopants [93,94].…”

Solution Synthesis, Surface Passivation, Optical Properties, Biomedical Applications, and Cytotoxicity of Silicon and Germanium Nanocrystals

“…Silicon and germanium NCs used in both in vitro and in vivo bioimaging applications are often excited by using UV sources; this potentially leads to autofluorescence and phototoxicity . Several solutions have been proposed, such as the use of two‐photon excitation (Figure c) . Gooding and co‐workers developed a series of solutions to minimize autofluorescence, particularly in the commonly encountered blue emitting silicon NCs .…”

Transition‐Metal‐Doped NIR‐Emitting Silicon Nanocrystals

“…[3,4] To date,m etal-doped SiNCs were obtained through am ultistep procedure starting from Fe-o rM n-doped alkali silicides, [5] and through hydride reduction of am ixture of silicon tetrachloride and am etal halide. [6] Thel atter process led to SiNCs doped with approximately 0.5 %t ransition metal, which emit blue to green light. Thet ransition metal-doped SiNCs reported herein incorporate no more than 0.2 %t ransition metal atoms,y et emit with absolute photoluminescence quantum yields (PL QY) as high as 26 %within the red-to-NIR spectral region.…”