Photon assisted-inversion of majority charge carriers in molecular semiconductor-based organic heterojunctions

Kikobo, Gracia Loma; Kumar, Abhishek; Vibhu, Vaibhav; Ouédraogo, Seydou; Deshotel, Alix; Mateos, Mickaël; Meunier‐Prest, Rita; Bouvet, Marcel

doi:10.1039/d0tc05828a

Cited by 11 publications

(27 citation statements)

References 58 publications

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“…This observation infers that interfacial charge transport gets faster with increasing applied bias, while bulk charge transport remains unchanged, which is a typical characteristic feature of bilayer heterojunction devices. [ 50 ] The rapid decrease in the R2 is attributed to the arrival of injected charges from the electrode to the R 2 ‐SiPc/LuPc 2 interface, which further populates it with accumulated mobile charges, thereby filling the traps and enhancing the charge mobility along the interface. Conversely, the mean variation of the mobile charges concentrated in the large bulk region does not change significantly with changing bias, keeping charge transport unchanged.…”

Section: Resultsmentioning

confidence: 99%

Molecular Engineering of Silicon Phthalocyanine to Improve the Charge Transport and Ammonia Sensing Properties of Organic Heterojunction Gas Sensors

Moorthy

King

Kumar

et al. 2022

Advanced Sensor Research

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Novel organic heterostructures fabricated with a bilayer consisting of an axially substituted silicon phthalocyanine (R 2 -SiPc) derivative and lutetium bis-phthalocyanine (LuPc 2 ) are investigated for their ammonia sensing properties. Surface and microstructure characterization of the heterostructure films reveal either compact or highly porous surface topography in (345F) 2 -SiPc and Cl 2 -SiPc-based heterostructures, while electrical characterization reveals a strong influence of the axial substituent in R 2 -SiPc on NH 3 sensing capabilities. Electrical characterization further demonstrates an apparent energy barrier for interfacial charge transport, which is higher in the (345F) 2 -SiPc/LuPc 2 heterojunction device. In-depth charge transport studies by impedance spectroscopy further reveal a resistive interface in (345F) 2 -SiPc/LuPc 2 and faster bulk and interfacial charge transport in Cl 2 -SiPc/LuPc 2 heterojunction devices. Different interfacial charge transport capabilities and surface topographies affect NH 3 sensing properties of the two heterojunction devices, in which (345F) 2 -SiPc/LuPc 2 reveals a fast and non-linear response with a limit of detection (LOD) of 310 ppb, while Cl 2 -SiPc/LuPc 2 exhibits a slow, and linear response to NH 3 with LOD of 100 ppb. Finally, different metrological parameters of the two sensors are correlated to the respective gas-material interactions, in which adsorption and diffusion regimes are modulated by the surface topography and hydrophobicity of the sensing layer.

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Section: Resultsmentioning

confidence: 99%

Molecular Engineering of Silicon Phthalocyanine to Improve the Charge Transport and Ammonia Sensing Properties of Organic Heterojunction Gas Sensors

Moorthy

King

Kumar

et al. 2022

Advanced Sensor Research

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“…410 °C. In the vacuum chamber, another IDE and glass plate were placed next The configuration of the workstation used for I-V measurements and NH 3 sensing was recently reported [40]. NH 3 sensing experiments were carried out in a dynamic way through alternate exposure to different concentrations of NH 3 (in the range of 10 to 90 ppm) for either 1 min or 10 min and recovery under clean air for either 4 or 40 minutes, at a fixed relative humidity (rh) of 40%.…”

Section: Device Development Characterizations and Nh 3 Sensingmentioning

confidence: 99%

“…On the other hand, Nyquist plots of pZnP-2 based DLH and of LuPc 2 resistor were fitted with one R1-CPE1 element, corresponding to the bulk resistance R1 and CPE1. Through the fitting, different circuit parameters such as resistance (R), α and effective capacitance (C eff ; defined by equation 2) were determined and have been used to describe the electrical nature of the devices [40].…”

Section: Charge Transport At the Pznp/lupc 2 Heterojunctionmentioning

confidence: 99%

Tuning of interfacial charge transport in polyporphine/phthalocyanine heterojunctions by molecular geometry control for an efficient gas sensor

Kumar

Mejjati

Meunier‐Prest

et al. 2022

Chemical Engineering Journal

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Owing to high interfacial conductivity, organic heterostructures hold great promises to augment the electrical performances of electronic devices. In this endeavor, the present work reports fabrication of novel polyporphine/phthalocyanine heterostructures and investigates the modulation of charge transport induced by structural change of polyporphine and its implication on ammonia sensing properties. Polyporphines materials are electrosynthesized by oxidation of zinc(II) porphine monomer that corresponds to the fully unsubstituted porphyrin. At less-positive anodic potential, low conducting meso,meso-singlylinked type-1 polymer (pZnP-1) is formed in which a monomer unit stays orthogonal to its neighbors. At higher anodic potential, monomer units are fused in the 2D plane to produce β,β-meso-meso-β,β-triply-fused type-2 polymer (pZnP-2), having a π-conjugated structure and high conductivity. Association of these polymers in organic heterojunction devices with lutetium bis-phthalocyanine (LuPc 2 ) reveals non-linear current-voltage (I-V) characteristics typical for interfacial accumulation of charges in the heterostructure for pZnP-1 and a linear I-V behavior for pZnP-2. Characterization of these heterojunctions by impedance spectroscopy further confirms the predominance of interfacial charge transport in pZnP-1/LuPc 2 which is improved with increasing bias, while largely bulk charge transport independent of bias prevails in pZnP-2/LuPc 2 device. Different regimes of charge transport influence ammoniasensing properties of the devices, such that pZnP-1/LuPc 2 demonstrates highly sensitive, reversible and stable response, while pZnP-2/LuPc 2 shows low and unstable response.

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“…Ammonia sensing studies were performed on a homebuilt workstation, which detailed configurations and operation have been described in our recent work [39]. Briefly, there are three interconnected fluidic lines for the calibrated gas flow of NH3, synthetic air and water vapor, which are also connected to the sensor test chamber of size 8 cm 3 .…”

Section: Sensor Development Characterizations and Nh3 Sensingmentioning

confidence: 99%

Interplay of electrode geometry and bias on charge transport in organic heterojunction gas sensors

Kumar

Meunier‐Prest

Lesniewska

et al. 2022

Sensors and Actuators B: Chemical

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Photon assisted-inversion of majority charge carriers in molecular semiconductor-based organic heterojunctions

Abstract: Ambipolar molecular materials hold great promises as a building block of next generation highly efficient, less complex and low cost electronics devices. In this endeavor, the present work reports the...

Cited by 11 publications

References 58 publications

Molecular Engineering of Silicon Phthalocyanine to Improve the Charge Transport and Ammonia Sensing Properties of Organic Heterojunction Gas Sensors

Molecular Engineering of Silicon Phthalocyanine to Improve the Charge Transport and Ammonia Sensing Properties of Organic Heterojunction Gas Sensors

Tuning of interfacial charge transport in polyporphine/phthalocyanine heterojunctions by molecular geometry control for an efficient gas sensor

Interplay of electrode geometry and bias on charge transport in organic heterojunction gas sensors

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