Two dibenzoheptazethrene isomers with low diradical character, large singlet–triplet gaps, and narrow energy gaps were synthesized. Both compounds exhibited remarkably high stability, which allowed for the fabrication of single-crystal field-effect transistors in air. A hole mobility of up to 0.15 cm2 V−1 s−1 was obtained with good bias-stress and storage stability.
Abstract
Singlet diradicaloids hold great potential as semiconductors for organic field-effect transistors (OFETs). However, their relative low material and device stabilities impede the practical applications. Here, to achieve balanced stability and performance, two isomeric dibenzoheptazethrene derivatives with singlet diradical character were synthesized in a concise manner. Benefitting from the aromatic stabilization, both compounds display a small diradical character and large singlet–triplet gap, as corroborated by variable-temperature electron paramagnetic resonance spectra, single-crystal analysis, and theoretical calculations. OFET devices based on single crystals showed a high hole mobility of 0.15 cm2 V−1 s−1, which is the highest for zethrene-based semiconductors. Both isomers exhibited remarkable material stability in air-saturated solutions as well as excellent bias-stress and storage stability in device under ambient air.
https://ift.tt/3pX1gFC
A new strongly electron‐accepting end group, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT), has been prepared by a one‐step sixfold nucleophilic substitution reaction. Cyanation results in a significant enhancement of the electron affinity in comparison to the fluorinated analogue, and the material demonstrates promising n‐type performance in solution processed organic field‐effect transistors with excellent stability.
Abstract
Reported here is a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a sixfold nucleophilic substitution with cyanide on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification significantly impacted the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge‐carrier mobility of up to μe≈0.15 cm2 V−1 s−1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.
https://ift.tt/3nmsW4W
I was just wondering which processing order is better for making BGBC OFETs. Is it:
-
doped-wafer plasma cleaning, octadecyltrichlorosilane (OTS) modification, gold deposition, and then organic semiconductor deposition, or
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doped-wafer plasma cleaning, gold deposition, OTS modification and then organic semiconductor deposition
I've been doing it the second way (before we shut down due to COVID) because I assume the gold adhesion would be better on SiO2 than on OTS, but my extracted mobility values have been incredibly low. Sometimes I don't get working devices at all. Is it better to do it the first way? For reference sake, this is a material that usually has field-effect mobility values that are 3 orders of magnitude higher in top contact devices. I know that bottom contact devices usually have lower mobility values due to contact resistance, but the output curves don't look too bad and I don't think the difference would be this significant. Thanks for any help anyone can provide.
Hello,
I'm a graduate student in chemistry. My lab is interdisciplinary, and we recently just expanded our engineering capabilities by purchasing a transistor testing station. We just started to make transistors, and I've run into some issues probing the gate electrode. Apparently what people do is simply scratch off the top layer of silicon dioxide to access the gate electrode, which is heavily doped silicon. I've gotten it to work once, but it's been inconsistent. One problem I have is that I'm not sure how deeply I need to scratch the wafer in order to access the gate. I was wondering if anybody had any tips, or perhaps a more reliable method of probing the gate electrode rather then simply scratching off the oxide layer of the wafer. Thanks for any help anybody can provide, and I apologize if this is the incorrect place to post this question.
http://onlinelibrary.wiley.com/doi/10.1002/adfm.201001031/full
EDIT: If you have access to that one, could you also post this one? http://onlinelibrary.wiley.com/doi/10.1002/adma.200902322/abstract
Thanks!
Also, if you're interested in the subject and want to share papers, I made a Mendeley group: http://www.mendeley.com/groups/576611/biodegradable-computing/
URI:https://onlinelibrary.wiley.com/doi/abs/10.1002/aelm.202101189
GRAPHENE NANORIBBON AS A FIELD EFFECT TRANSISTOR AND PERFORMANCE ANALYSIS AGAINST FINFET Abstract- Graphene is a widely .
I'm confused, I get the basic principle of FETs, but now I've read a paper where a single layer of MoS2 is used to fabricate a FET, but there is no doping. Shouldn't there be pnp junctions? Instead there is just a single layer of MoS2 (which is probably an n type semiconductor due to sulfur vacancies).
Can someone explain why this works as a FET? Does the SiO2 substrate act as a p-type semiconductor? That's the only explanation I was able to come up with.
A MOF thin film‐based bionic proton field‐effect transistor (H+‐FET) has been fabricated for the first time. It displays the highest proton mobility and highest on–off ratio among all reported H+‐FETs.
Abstract
The construction of hydrophobic nanochannel with hydrophilic sites for bionic devices to proximally mimick real bio‐system is still challenging. Taking the advantages of MOF chemistry, a highly oriented CuTCPP thin film has been successfully reconstructed with ultra‐thin nanosheets to produce abundant two‐dimensional interstitial hydrophobic nanochannels with hydrophilic sites. Different from the classical active‐layer material with proton transport in bulk, CuTCPP thin film represents a new type of active‐layer with proton transport in nanochannel for bionic proton field‐effect transistor (H+‐FETs). The resultant device can reversibly modulate the proton transport by varying the voltage on its gate electrode. Meanwhile, it shows the highest proton mobility of ≈9.5×10−3 cm2 V−1 s−1 and highest on‐off ratio of 4.1 among all of the reported H+‐FETs. Our result demonstrates a powerful material design strategy for proximally mimicking the structure and properties of bio‐systems and constructing bionic electrical devices.
https://ift.tt/3f9oIfy
Singlet diradicaloids hold great potential as semiconductors for organic field-effect transistors (OFETs). However, their relative low material and device stabilities impede the practical applications. Here, to achieve balanced stability and performance, two isomeric dibenzoheptazethrene derivatives with singlet diradical character were synthesized in a concise manner. Benefitted from the aromatic stabilization, both compounds displayed small diradical character and large singlet-triplet gap, as corroborated by variable temperature electron paramagnetic resonance spectra, single crystal analysis and theoretical calculations. OFET devices based on single crystals showed high hole mobility of 0.15 cm 2 V -1 s -1 , which is the highest for zethrene-based semiconductors. Both isomers exhibited remarkable material stability in air-saturated solutions and excellent bias-stress and storage stability in device under ambient air.
https://ift.tt/3v4eaDO
A new strongly electron‐accepting end group, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT), has been prepared by a one‐step sixfold nucleophilic substitution reaction. Cyanation results in a significant enhancement of the electron affinity in comparison to the fluorinated analogue, and the material demonstrates promising n‐type performance in solution processed organic field‐effect transistors with excellent stability.
Abstract
Reported here is a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a sixfold nucleophilic substitution with cyanide on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification significantly impacted the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge‐carrier mobility of up to μe≈0.15 cm2 V−1 s−1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.
https://ift.tt/3nmsW4W
We report a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a six‐fold nucleophilic substitution with cyanides on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification was found to significantly impact the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The highly electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge carrier mobility of up to µ e ≈ 0.15 cm 2 V ‐1 s ‐1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.
https://ift.tt/3nmsW4W
