Light Harvesting and Energy Transfer in Multiporphyrin-Modified CdSe Nanoparticles

✍ Scribed by Soonchul Kang; Masakazu Yasuda; Hiroshi Miyasaka; Hironobu Hayashi; Mitsuo Kawasaki; Tomokazu Umeyama; Yoshihiro Matano; Kaname Yoshida; Seiji Isoda; Hiroshi Imahori

• Publisher: Wiley (John Wiley & Sons)
• Year: 2008
• Tongue: English
• Weight: 501 KB
• Volume: 1
• Category: Article
• ISSN: 1864-5631
• DOI: 10.1002/cssc.200700138

✦ Synopsis

Abstract

Multiporphyrin‐modified CdSe nanoparticles (CdSe‐H~2~P) were prepared to elucidate the interaction between chromophores and luminescent semiconducting nanoparticles in the excited and ground states. The CdSe‐H~2~P nanoparticles were obtained by place‐exchange reactions of hexadecylamine‐thiophenol‐modified CdSe nanoparticles with porphyrin alkanethiols in toluene. The number of porphyrin molecules on the surface of a single CdSe nanoparticle increased with increasing reaction time to reach a saturated maximum of 21. The porphyrins as well as the core in CdSe‐H~2~P can absorb UV/Vis radiation. Steady‐state emission and emission‐lifetime measurements reveal efficient energy transfer from the CdSe excited state to the porphyrins in the CdSe‐H~2~P nanoparticles. The resulting porphyrin excited singlet state is not quenched by the CdSe core. These unique properties are in sharp contrast with those of multiporphyrin‐modified metal and silica nanoparticles. Thus, semiconducting nanoparticle–multiporphyrin composites are highly promising as novel artificial photosynthetic materials.