Si QDs can be prepared using a variety of techniques such as wet chemical reduction [10–18], metathesis reaction [19], disproportionation reaction [20, 21], thermal annealing of Si-rich SiC [22], electrochemical etching [23], plasma synthesis or plasma-enhanced chemical vapor deposition (PECVD) [24–27], and high-temperature hydrogen reduction method [28–32]. Because Si QDs are chemically active, their surface should be passivated for further use. Molecules with alkyl chains and -CH3, -COOH, or -NH2 ends have been widely employed as surface ligands to enhance the stability of Si QDs [28–36]. These ligands help prevent the

oxidation of silicon and enhance the dispersibility selleck chemicals llc of Si QDs in organic or aqueous solution. In addition to the surface protection, optoelectronic functional molecules as ligands of Si QDs are attracting increasing interest in recent years for the crucial role of the ligands to the interfacial related process in optoelectronic or light-harvesting devices. Kryschi and co-workers showed that 3-vinylthiophene ligands may act as surface-bound antennae that mediate ultrafast electron transfer or excitation energy transfer across the Si QD interface via high-energy two-photon excitation

[37, 38]. They also reported that for 2- and 4-vinylpyridine-terminated Si QDs, ultrafast excitation relaxation dynamics involving decay and rise dynamics faster than 1 ps were GSK 3 inhibitor ascribed to electronic excitation energy transfer from an initially photoexcited ligand state to Si QD conduction band states [39]. Larsen

and Kauzlarich and their co-workers investigated the transient dynamics of 3-aminopropenyl-terminated Si QDs [40]. A formation and decay of a charge transfer excited state between the delocalized π electrons of the carbon linker and the Si core excitons were proposed to interpret one-photon excitation. Zuilhof et al. reported Si QDs functionalized with a red-emitting ruthenium complex to exhibit Förster resonance energy transfer (FRET) from Si QDs to the complex [41]. The ligands on the Si surface may also induce optoelectronic interactions to other QDs such as CdSe QDs, e.g., Sudeep and Emrick found that hydrosilylation of Si QDs provides a corona of phosphine CYTH4 oxides that may serve as ligands for CdSe QDs [42]. This surface functionalization of the Si QDs was proved a key to the photoluminescence quenching of CdSe QDs, as conventional (alkane-covered) Si QD samples give no evidence of such optoelectronic interactions. Recently, we reported 9-ethylanthracene-modified Si QDs showing dual emission peaks that originate from the Si QD core and the ligands [43]. In this report, we demonstrate the synthesis and surface modification of Si QDs with N-ethylcarbazole, using hydrogen-terminated Si QDs and N-vinylcarbazole as the starting materials.