Synthesis and Improved Photoresponse of Silicon Nanoparticle Heterostructures

In this paper, we have synthesized silicon nanoparticles (SiNPs) via a simple, scalable hydrothermal method using 3-(2-aminoethylamino)propyl trimethoxysilane (AEAPTMS) as the Si precursor and L-ascorbic acid (L-AA) as the reductant. In order to improve carrier transport in the synthesized NPs to enhance their applicability in optoelectronic devices, a surface modification process had been carried out to replace the original long-chain dehydroascorbic acid (DHA) ligand with a shorter-chain 3-mercaptopropionic acid (MPA) ligand. A hybrid test structure was then fabricated composed of the surface-modified SiNP layer with a conductive polymer, PEDOT:PSS, which served as the hole transport layer. This SiNP-PEDOT:PSS planar heterostructure served as a platform to probe the photoresponse and carrier dynamics of the modified nanoparticles. Compared to the as-synthesized SiNPs, the surface-modified SiNPs achieved a 20% increase in carrier lifetime and an on/off ratio of 7.28 at ±1 V applied bias under UV illumination. These findings highlight the potential of SiNPs for integration into solution-processed optoelectronic devices.