Pronounced Photovoltaic Response from Multilayered Transition-Metal Dichalcogenides PN-Junctions

Memaran, Shahriar; Pradhan, Nihar; Lu, Zhengguang; Rhodes, Daniel; Ludwig, Jonathan; Zhou, Qiong; Ogunsolu, Omotola O.; Ajayan, Pulickel M.; Smirnov, Dmitry; Fernández‐Domínguez, Antonio I.; García‐Vidal, F. J.; Balicas, Luis

doi:10.1021/acs.nanolett.5b03265

Cited by 111 publications

(99 citation statements)

References 43 publications

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“…Power conversion efficiency η = P in /P el (P in incidenct light power; P el , electrical output power) of the solar cells was found to be on the order of 0.5% limited by the low absorption in the monolayer and recombination of charge carriers. In a similar device structure, Memaran et al [96] demonstrated η > 14% and fill factors of~70% at AM-1.5 spectral irradiation, using multi-layer MoSe 2 . Similar results were obtained by other groups [97] and for a MoS 2 /black phosphorus solar cell [98].…”

Section: Photovoltaicsmentioning

confidence: 98%

Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

2016

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Abstract:We review the application of atomically thin transition metal dichalcogenides in optoelectronic devices. First, a brief overview of the optical properties of two-dimensional layered semiconductors is given and the role of excitons and valley dichroism in these materials are discussed. The following sections review and compare different concepts of photodetecting and light emitting devices, nanoscale lasers, single photon emitters, valleytronics devices, as well as photovoltaic cells. Lateral and vertical device layouts and different operation mechanisms are compared. An insight into the emerging field of valley-based optoelectronics is given. We conclude with a critical evaluation of the research area, where we discuss potential future applications and remaining challenges.

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Section: Photovoltaicsmentioning

confidence: 98%

Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

2016

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“…The quantity limiting further efficiency improvement is the open circuit voltage (VOC), whose importance as a key parameter has been largely overlooked, and thus paths to voltage improvement remain largely uninvestigated. Despite recent reports of high absorber material radiative efficiencies, an overwhelming majority of the reported VOC values for TMDC and other 2D semiconductors based photovoltaic devices are < 0.5 V 1, 5, 14-15 with record values of only ~0.8-0.9 V in split gated, in-plane homojunction devices 66,68 . This implies a bandgap-Voc offset (Woc = Eg -Voc) > 0.8 V for most 2D semiconductor photovoltaic structures reported to date.…”

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confidence: 96%

Van der Waals Materials for Atomically-Thin Photovoltaics: Promise and Outlook

et al. 2017

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Two-dimensional (2D) semiconductors provide a unique opportunity for optoelectronics due to their layered atomic structure, electronic and optical properties. To date, a majority of the application-oriented research in this field has been focused on fieldeffect electronics as well as photodetectors and light emitting diodes. Here we present a perspective on the use of 2D semiconductors for photovoltaic applications. We discuss photonic device designs that enable light trapping in nanometer-thickness absorber layers, and we also outline schemes for efficient carrier transport and collection. We further provide theoretical estimates of efficiency indicating that 2D semiconductors can indeed be competitive with and complementary to conventional photovoltaics, based on favorable energy bandgap, absorption, external radiative efficiency, along with recent experimental demonstrations. Photonic and electronic design of 2D semiconductor photovoltaics represents a new direction for realizing ultrathin, efficient solar cells with applications ranging from conventional power generation to portable and ultralight solar power. *Corresponding author: haa@caltech.eduKeywords: Transition metal dichalcogenides, heterostructures, light-trapping, ShockleyQuessier, nanophotonics, 2D materials Since the isolation of graphene as the first free-standing two-dimensional (2D) material (from graphite), the class of layered 2D materials with weak van der Waals inter-planar bonding has expanded significantly. Two-dimensional materials now span a great diversity of atomic structure and physical properties. Prominent among these are the semiconductor chalcogenides of transition and basic metals (Mo, W, Ga, In, Sn, Re etc.) 1-3 , as well as layered allotropes of other p-block elements of the periodic table such as P, As, Te etc. 4 The availability of atomic layer thickness samples of stable, passivated, and dangling bond free semiconductor materials ushers in a new phase in solid state device design and optoelectronics.1, 5-8 A notable feature of the metal chalcogenide 2D semiconductors is the transition from an indirect bandgap in bulk to direct bandgap (Eg) in monolayer form, resulting in a high photoluminescence quantum yield (PL QY) [9][10] in turn corresponding to high radiative efficiency. This combined with the bandgap ranging from visible to near infrared part of the spectrum (1.1 to 2.0 eV) 1 makes the chalcogenides

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“…Recently studied two-dimensional systems such as semiconducting transition metal dichalcogenides (TMDCs) with finite bandgaps1112 have been shown to be very promising for ultrathin and flexible energy conversion and storage devices1314151617. Due to the parallel bands in their density of states or the so-called band nesting effect18, these atomically thin materials present strong optical responses even for excitation energies far exceeding their bandgaps.…”

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confidence: 99%

Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer

et al. 2017

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In emerging optoelectronic applications, such as water photolysis, exciton fission and novel photovoltaics involving low-dimensional nanomaterials, hot-carrier relaxation and extraction mechanisms play an indispensable and intriguing role in their photo-electron conversion processes. Two-dimensional transition metal dichalcogenides have attracted much attention in above fields recently; however, insight into the relaxation mechanism of hot electron-hole pairs in the band nesting region denoted as C-excitons, remains elusive. Using MoS2 monolayers as a model two-dimensional transition metal dichalcogenide system, here we report a slower hot-carrier cooling for C-excitons, in comparison with band-edge excitons. We deduce that this effect arises from the favourable band alignment and transient excited-state Coulomb environment, rather than solely on quantum confinement in two-dimension systems. We identify the screening-sensitive bandgap renormalization for MoS2 monolayer/graphene heterostructures, and confirm the initial hot-carrier extraction for the C-exciton state with an unprecedented efficiency of 80%, accompanied by a twofold reduction in the exciton binding energy.

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Pronounced Photovoltaic Response from Multilayered Transition-Metal Dichalcogenides PN-Junctions

Cited by 111 publications

References 43 publications

Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

Van der Waals Materials for Atomically-Thin Photovoltaics: Promise and Outlook

Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer

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