Highly anisotropic and robust excitons in monolayer black phosphorus

Wang, Xiaomu; Jones, Aaron M.; Seyler, Kyle L.; Tran, Vy; Jia, Yaqi; Zhao, Huan; Wang, Han; Yang, Li; Xu, Xiaodong; Xia, Fengnian

doi:10.1038/nnano.2015.71

Cited by 1,337 publications

(1,315 citation statements)

References 34 publications

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“…It is well known that even though the LDA is able to reproduce most of the interesting physics of a system, it underestimates the size of the band gap. Indeed, spectroscopy based measurements revealed that the band gap of phosphorene (∼2.2 eV) is larger than that reported here within the DFT/LDA framework [9]. Also the largest uncertainty in predicting the accurate position of a defect state has been a problem related to the band gap as computed with semi-local DFT xc-functionals.…”

Section: Ab Initio Schemecontrasting

confidence: 53%

Effect of atomic-scale defects and dopants on phosphorene electronic structure and quantum transport properties

López-Bezanilla

2016

Phys. Rev. B

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By means of a multi-scale first-principles approach, a description of the local electronic structure of two-dimensional and narrow phosphorene sheets with various types of modifications is presented. Firstly, a rational argument based on the geometry of the pristine and modified P network, and supported by the Wannier functions formalism is introduced to describe a hybridization model of the P atomic orbitals. Ab initio calculations show that non-isoelectronic foreign atoms form quasibound states at varying energy levels and create different polarization states depending on the number of valence electrons between P and the doping atom. The quantum transport properties of modified phosphorene ribbons are further described with great accuracy. The distortions on the electronic bands induced by the external species lead to strong backscattering effects on the propagating charge carriers. Depending on the energy of the charge-carrier and the type of doping, the conduction may range from the diffusive to the localized regime. Interstitial defects at vacant sites lead to homogeneous transport fingerprints across different types of doping atoms. We suggest that the relatively low values of charge mobility reported in experimental measurements may have their origin in the presence of defects.

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Section: Ab Initio Schemecontrasting

confidence: 53%

Effect of atomic-scale defects and dopants on phosphorene electronic structure and quantum transport properties

López-Bezanilla

2016

Phys. Rev. B

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“…BP nanosheets are a type of 2D nanomaterials with unique properties such as a tunable band gap, high NIR absorption, and high photothermal conversion efficiency 33, 34, 35, 36, 37, 38, 39, 40. As an inorganic nanoagent, BP nanosheets are attractive due to the inherent biocompatibility since phosphorus is a vital element, especially in bones, making up about 1% of the human body weight 41, 42, 43.…”

Section: Introductionmentioning

confidence: 99%

Black‐Phosphorus‐Incorporated Hydrogel as a Sprayable and Biodegradable Photothermal Platform for Postsurgical Treatment of Cancer

et al. 2018

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Photothermal therapy (PTT) is a fledgling therapeutic strategy for cancer treatment with minimal invasiveness but clinical adoption has been stifled by concerns such as insufficient biodegradability of the PTT agents and lack of an efficient delivery system. Here, black phosphorus (BP) nanosheets are incorporated with a thermosensitive hydrogel [poly(d,l‐lactide)‐poly(ethylene glycol)‐poly(d,l‐lactide) (PDLLA‐PEG‐PDLLA: PLEL)] to produce a new PTT system for postoperative treatment of cancer. The BP@PLEL hydrogel exhibits excellent near infrared (NIR) photothermal performance and a rapid NIR‐induced sol–gel transition as well as good biodegradability and biocompatibility in vitro and in vivo. Based on these merits, an in vivo PTT postoperative treatment strategy is established. Under NIR irradiation, the sprayed BP@PLEL hydrogel enables rapid gelation forming a gelled membrane on wounds and offers high PTT efficacy to eliminate residual tumor tissues after tumor removal surgery. Furthermore, the good photothermal antibacterial performance prevents infection and this efficient and biodegradable PTT system is very promising in postoperative treatment of cancer.

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“…Particularly, monolayer phosphorene is expected to be much less stable than few-layer phosphorene 16 , hence making its identification and characterization extremely challenging. There is a huge controversy on the identification of very few-layer (one or two layers) phosphorene and thus on their properties [16][17][18] . This controversy was primarily due to the lack of a robust experimental technique to precisely identify the monolayer phosphorene.…”

Section: Introductionmentioning

confidence: 99%

Optical tuning of exciton and trion emissions in monolayer phosphorene

et al. 2015

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Monolayer phosphorene provides a unique two-dimensional (2D) platform to investigate the fundamental dynamics of excitons and trions (charged excitons) in reduced dimensions. However, owing to its high instability, unambiguous identification of monolayer phosphorene has been elusive. Consequently, many important fundamental properties, such as exciton dynamics, remain underexplored. We report a rapid, noninvasive, and highly accurate approach based on optical interferometry to determine the layer number of phosphorene, and confirm the results with reliable photoluminescence measurements. Furthermore, we successfully probed the dynamics of excitons and trions in monolayer phosphorene by controlling the photo-carrier injection in a relatively low excitation power range. Based on our measured optical gap and the previously measured electronic energy gap, we determined the exciton binding energy to be ,0.3 eV for the monolayer phosphorene on SiO 2 /Si substrate, which agrees well with theoretical predictions. A huge trion binding energy of ,100 meV was first observed in monolayer phosphorene, which is around five times higher than that in transition metal dichalcogenide (TMD) monolayer semiconductor, such as MoS 2 . The carrier lifetime of exciton emission in monolayer phosphorene was measured to be ,220 ps, which is comparable to those in other 2D TMD semiconductors. Our results open new avenues for exploring fundamental phenomena and novel optoelectronic applications using monolayer phosphorene. Keywords: exciton; monolayer phosphorene; optical injection; two-dimensional materials INTRODUCTION Phosphorene is a recently developed two-dimensional (2D) material that has attracted tremendous attention owing to its unique anisotropic manner 1-6 , layer-dependent direct band gaps 7,8 , and quasi-onedimensional (1D) excitonic nature 9,10 , which are all in drastic contrast with the properties of other 2D materials, such as graphene 11 and transition metal dichalcogenide (TMD) semiconductors [12][13][14] . Monolayer phosphorene has been of particular interest in exploring technological applications and investigating fundamental phenomena, such as 2D quantum confinement and many-body interactions 9,15 . However, such unique 2D materials are unstable in ambient conditions and degrade quickly 8,16 . Particularly, monolayer phosphorene is expected to be much less stable than few-layer phosphorene 16 , hence making its identification and characterization extremely challenging. There is a huge controversy on the identification of very few-layer (one or two layers) phosphorene and thus on their properties [16][17][18] . This controversy was primarily due to the lack of a robust experimental technique to precisely identify the monolayer phosphorene. Consequently, many important fundamental properties of monolayer phosphorene, such as its excitonic nature, remain elusive. In this study, we propose and implement a rapid, noninvasive,

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Highly anisotropic and robust excitons in monolayer black phosphorus

Cited by 1,337 publications

References 34 publications

Effect of atomic-scale defects and dopants on phosphorene electronic structure and quantum transport properties

Effect of atomic-scale defects and dopants on phosphorene electronic structure and quantum transport properties

Black‐Phosphorus‐Incorporated Hydrogel as a Sprayable and Biodegradable Photothermal Platform for Postsurgical Treatment of Cancer

Optical tuning of exciton and trion emissions in monolayer phosphorene

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