We report the implementation of continuous, highly flexible, and transparent graphene films obtained by chemical vapor deposition (CVD) as transparent conductive electrodes (TCE) in organic photovoltaic cells. Graphene films were synthesized by CVD, transferred to transparent substrates, and evaluated in organic solar cell heterojunctions (TCE/poly-3,4-ethylenedioxythiophene:poly styrenesulfonate (PEDOT:PSS)/copper phthalocyanine/fullerene/bathocuproine/aluminum). Key to our success is the continuous nature of the CVD graphene films, which led to minimal surface roughness (∼0.9 nm) and offered sheet resistance down to 230 Ω/sq (at 72% transparency), much lower than stacked graphene flakes at similar transparency. In addition, solar cells with CVD graphene and indium tin oxide (ITO) electrodes were fabricated side-by-side on flexible polyethylene terephthalate (PET) substrates and were confirmed to offer comparable performance, with power conversion efficiencies (η) of 1.18 and 1.27%, respectively. Further...

Continuous, highly flexible, and transparent graphene films by chemical vapor deposition for organic photovoltaics.

We report the implementation of continuous, highlyflexible, and transparent graphenefilms obtained by chemical vapor deposition (CVD) as transparent conductive electrodes (TCE) in organic photovoltaic cells. Graphene films were synthesized by CVD, transferred to transparent substrates, and evaluated in organic solar cell heterojunctions (TCE/poly-3,4-ethylenedioxythiophene:poly styrenesulfonate (PEDOT:PSS)/copper phthalocyanine/fullerene/bathocuproine/aluminum). Key to our success is the continuous nature of the CVD graphenefilms,whichledtominimalsurfaceroughness(0.9nm)andofferedsheetresistancedownto230/ sq (at 72% transparency), much lower than stacked grapheneflakes at similar transparency. In addition, solar cellswithCVDgrapheneandindiumtinoxide(ITO)electrodeswerefabricatedside-by-sideonflexiblepolyethylene terephthalate (PET) substrates and were confirmed to offer comparable performance, with power conversion efficiencies()of1.18and1.27%,respectively.Furthermore,CVDgraphenesolarcellsdemonstratedoutstanding capability to operate under bending conditions up to 138°, whereas the ITO-based devices displayed cracks and irreversiblefailureunderbendingof60°.OurworkindicatesthegreatpotentialofCVDgraphenefilmsforflexible photovoltaic applications.

Continuous, Highly Flexible, and Transparent Graphene Films by Chemical Vapor Deposition for Organic

A review of recent MOSFET threshold voltage extraction methods

Two-dimensional (2D) materials have attracted a great deal of interest in recent years. This family of materials allows for the realization of versatile electronic devices and holds promise for next-generation (opto)electronics. Their electronic properties strongly depend on the number of layers, making them interesting from a fundamental standpoint. For electronic applications, semiconducting 2D materials benefit from sizable mobilities and large on/off ratios, due to the large modulation achievable via the gate field-effect. Moreover, being mechanically strong and flexible, these materials can withstand large strain (>10%) before rupture, making them interesting for strain engineering and flexible devices. Even in their single layer form, semiconducting 2D materials have demonstrated efficient light absorption, enabling large responsivity in photodetectors. Therefore, semiconducting layered 2D materials are strong candidates for optoelectronic applications, especially for photodetection. Here, we review the state-of-the-art in photodetectors based on semiconducting 2D materials, focusing on the transition metal dichalcogenides, novel van der Waals materials, black phosphorus, and heterostructures.

Photocurrent generation with two-dimensional van der Waals semiconductors.

Ambipolar transport, necessary to realise PN-junctions, is unfortunately missing from most two-dimensional semiconductors. Here, the authors fabricate few-layer black phosphorous field-effect transistors, define PN-junctions and demonstrate full electrostatic control of the device by means of local gating.

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Photovoltaic effect in few-layer black phosphorus PN junctions defined by local electrostatic gating.

New method to extract the model parameters of solar cells from the explicit analytic solutions of their illuminated I–V characteristics

Revisiting MOSFET threshold voltage extraction methods

In this paper, we review the compact-modeling framework for undoped double-gate (DG) silicon-on-insulator (SOI) MOSFETs. The use of multiple gates has emerged as a new technology to possibly replace the conventional planar MOSFET when its feature size is scaled to the sub-50-nm regime. MOSFET technology has been the choice for mainstream digital circuits for very large scale integration as well as for other high-frequency applications in the low-gigahertz range. But the continuing scaling of MOSFET presents many challenges, and multiple-gate, particularly DG, SOI devices seem to be attractive alternatives as they can effectively reduce the short-channel effects and yield higher current drive. Core compact models, including the analysis for surface potential and drain-current, for both the symmetric and asymmetric DG SOI MOSFETs, are discussed and compared. Numerical simulations are also included in order to assess the validity of the models reviewed

A Review of Core Compact Models for Undoped Double-Gate SOI MOSFETs

Exact closed form solutions based on the Lambert W-function are presented to express the forward current‐voltage characteristics of non-ideal single-exponential diodes containing all possible combinations of series and shunt parasitic resistances. It is shown that these expressions could be useful for carrying out highly accurate computations at speeds almost as fast as those possible when using less precise approximate solutions based on common elementary functions. ” 2000 Published by Elsevier Science Ltd. All rights reserved.

Technical Note Exact analytical solutions of the forward non-ideal diode equation with series and shunt parasitic resistances

Exact closed form solutions based on the Lambert W-function are presented to express the forward current–voltage characteristics of non-ideal single-exponential diodes containing all possible combinations of series and shunt parasitic resistances. It is shown that these expressions could be useful for carrying out highly accurate computations at speeds almost as fast as those possible when using less precise approximate solutions based on common elementary functions.

Juan Muci

Papers

New method to extract the model parameters of solar cells from the explicit analytic solutions of their illuminated I–V characteristics

Revisiting MOSFET threshold voltage extraction methods

A Review of Core Compact Models for Undoped Double-Gate SOI MOSFETs

Technical Note Exact analytical solutions of the forward non-ideal diode equation with series and shunt parasitic resistances

Exact analytical solutions of the forward non-ideal diode equation with series and shunt parasitic resistances