Ultrafast Electron Transfer Dynamics in CdSe/CdTe Donor−Acceptor Nanorods

Abstract

Photoinduced charge transfer dynamics in type-II CdSe/CdTe donor−acceptor nanorods were studied in real-time using femtosecond broadband pump−probe spectroscopy. Following photoexcitation of CdTe (λex = 620 nm), spectral bleaching from the state-filling signals of the band-edge optical transitions was measured using a femtosecond white light pulse (λprobe = 350−750 nm). Excitation of the lowest energy CdTe transition shows an ultrafast change in the bleaching signals of both the CdTe and CdSe lowest energy 1S transitions as well as the characteristic carrier transfer band. Our results indicate that interfacial interconduction band electron transfer CdTe to CdSe occurs on the 500 fs time scale in these heteromaterials.

Colloidal synthesis and characterization of CdSe/CdTe core/shell nanowire heterostructures

“…After the electron migration, most of the electrons occupy the CdSe band edge, so that the final TA spectra shape of the CdSe/ CdTe core/shell NWs looks very close to that of the bare CdSe NWs. The extracted interfacial electron migration time constant (800 fs) is in good agreement with the previously reported electron transfer rate for the CdSe/CdTe core/shell NPs [27,41].…”

“…Although great progress has been made in synthesizing core/shell NPs using the colloidal approach [13][14][15]17,19], only few successes have been made in the synthesis of core/shell NRs [12,26,27]. Unfortunately, even less work, to the best of our knowledge, has been reported on the colloidal synthesis of core/ shell NWs.…”

Physical properties of elongated inorganic nanoparticles

“…In many cases, the appropriate choice of materials and the geometry allows to obtain suitable energy gaps for the targeted application. Among the rod-like type-II nanostructures that have been fabricated so far, we find dot-in-a-rod structures [17,148,149], collinear nanorods [150][151][152][153][154][155][156], nanobarbells [157,158] and magnetic-semiconductor nanorods [159,160].…”

Ultrafast Spectroscopy and Red Emission from β-Ga2O3/β-Ga2S3 Nanowires

“…Furthermore, there appears to be a broad absorption below the band edge for all the samples most likely due to the defect states present. Unfortunately, the absorption spectra for the β-Ga 2 O 3 /β-Ga 2 S 3 NWs do not provide any clear evidence of the type of band offset that may exist between this hetero-structure [22]. Nevertheless, transient PL and differential absorption measurements indicate that the main contribution of both signals is coming from Ga 2 S 3 suggesting a type I heterojunction.…”