Addressable photocharging of single quantum dots assisted with atomic force microscopy probe

Dokukin, Maxim; Olac-vaw, Roman; Guz, Nataliia; Mitin, V. I.; Sokolov, Igor

doi:10.1063/1.3254895

“…One might expect that assembling several quantum dots together, one could get nanoparticles of larger size, and expectedly, higher brightness. However, it is impractical because quantum dots quench their fluorescence when the distance between them is less than ~10 nm 13,39 . Fig.…”

Section: Physical Characteristics Of Ca-dotsmentioning

confidence: 99%

Ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications

Peng

¹

,

Almeqdadi

²

,

Laroche

³

et al. 2019

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Cellulose acetate (CA), viscose, or artificial silk are biocompatible human-benign derivatives of cellulose, one of the most abundant biopolymers on earth. While various optical materials have been developed from CA, optical CA nanomaterials are nonexistent. Here we report on the assembly of a new family of extremely bright fluorescent CA nanoparticles (CA-dots), which are fully suitable for in vivo imaging / targeting applications. CA-dots can encapsulate a variety of molecular fluorophores. Using various commercially available fluorophores, we demonstrate that *

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“…For quantitative analysis, the tip-sample system is simply treated as a plane capacitor, and the capacitive electrostatic force gradient would cause a phase shift when applying a bias between the tip and sample. With charges trapped in the nanostructures by laser irradiation, additional phase shift induced by the Coulombic force would be generated [45]. The phase shift detected by EFM can be described as [46][47]…”

Section: Photo-generated Trapped Charges and Barrier Height Modificationmentioning

confidence: 99%

Photoelectrical properties investigated on individual Si nanowires and their size dependence

Hu

¹

,

Li

²

,

Jiang

³

et al. 2020

Preprint

0

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Periodically ordered arrays of vertically aligned Si nanowires (Si NWs) are successfully fabricated with controllable diameters and lengths. Their photoconductive properties are investigated by photoconductive atomic force microscopy (PCAFM) on individual nanowires. The results show that the photocurrent of Si NWs increases significantly with the laser intensity, indicating that Si NWs have good photoconductance and photoresponse capability. This photo-enhanced conductance can be attributed to the photo-induced Schottky barrier change, confirmed by I-V curve analyses. On the other hand, electrostatic force microscopy (EFM) results indicate that a large number of photo-generated charges are trapped in Si NWs under laser irradiation, leading to the lowering of barrier height. Moreover, the size dependence of photoconductive properties is studied on Si NWs with different diameters and lengths. It is found that the increasing magnitude of photocurrent with laser intensity is greatly relevant to the nanowires’ diameter and length. Si NWs with smaller diameters and shorter lengths display better photoconductive properties, which agrees well with the size-dependent barrier height variation induced by photo-generated charges. With optimized diameter and length, great photoelectrical properties are achieved on Si NWs. Overall, in this study the photoelectrical properties of individual Si NWs are systematically investigated by PCAFM and EFM, providing important information for the optimization of nanostructures for practical applications.

show abstract

“…For quantitative analysis, the tip-sample system is simply treated as a plane capacitor, and the capacitive electrostatic force gradient would cause a phase shift when applying a bias between the tip and sample. With charges trapped in the nanostructures by laser irradiation, additional phase shift induced by the Coulombic force would be generated [53]. The phase shift detected by EFM can be described as [54][55]…”

Section: Photo-generated Trapped Charges and Barrier Height Modificationmentioning

confidence: 99%

Photoelectrical properties investigated on individual Si nanowires and their size dependence

Hu

¹

,

Li

²

,

Yang

³

2020

Preprint

0

View full text Add to dashboard Cite

Periodically ordered arrays of vertically aligned Si nanowires (Si NWs) are successfully fabricated with controllable diameters and lengths. Their photoconductive properties are investigated by photoconductive atomic force microscopy (PCAFM) on individual nanowires. The results show that the photocurrent of Si NWs increases significantly with the laser intensity, indicating that Si NWs have good photoconductance and photoresponse capability. This photo-enhanced conductance can be attributed to the photo-induced Schottky barrier change, confirmed by I-V curve analyses. On the other hand, electrostatic force microscopy (EFM) results indicate that a large number of photo-generated charges are trapped in Si NWs under laser irradiation, leading to the lowering of barrier height. Moreover, the size dependence of photoconductive properties is studied on Si NWs with different diameters and lengths. It is found that the increasing magnitude of photocurrent with laser intensity is greatly relevant to the nanowires’ diameter and length. Si NWs with smaller diameters and shorter lengths display better photoconductive properties, which agrees well with the size-dependent barrier height variation induced by photo-generated charges. With optimized diameter and length, great photoelectrical properties are achieved on Si NWs. Overall, in this study the photoelectrical properties of individual Si NWs are systematically investigated by PCAFM and EFM, providing important information for the optimization of nanostructures for practical applications.

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Addressable photocharging of single quantum dots assisted with atomic force microscopy probe

Cited by 15 publications

References 21 publications

Ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications

Ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications

Photoelectrical properties investigated on individual Si nanowires and their size dependence

Photoelectrical properties investigated on individual Si nanowires and their size dependence

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