Exploring the hole mobility of oligothiophene based donors with different spatial symmetry and conjugation length of backbone: A theoretical insight

Author(s):  
Guojia Zhu ◽  
Shaohui Zheng
Author(s):  
Satomi Hosokawa ◽  
Eri Tomita ◽  
Shinji Kanehashi ◽  
Kenji Ogino

Abstract We reported that supercritical (sc) annealing of poly(3-hexylthiophene) (P3HT), and its block copolymers with poly(ethylene oxide) (PEO) and polystyrene (PSt) brought about improvements in the crystal structure and hole mobility, determined by the space charge limited current (SCLC) measurement. P3HT-b-PEO showed the largest increase in mobility. From XRD profile, it was found that the treatment with scCO2 increased the crystallite size and crystallinity. UV-vis spectra showed that the effective conjugation length in the scCO2 treated films was increased compared to the as-spun, suggesting that CO2 molecules are incorporated into domains of the second block domains and P3HT amorphous region, and assist to alter the characteristics of the crystalline region. Then, it was considered that the change in the crystalline structure and the improvement of P3HT chains packing led to the enhanced mobility. Since PEO is known to have a higher affinity for CO2, the increase of mobility was specifically intensive.


2017 ◽  
Vol 15 (3) ◽  
pp. 41
Author(s):  
Zoltán Szűts ◽  
Jinil Yoo

Tanulmányunk témája a netsemlegesség. Először magát a fogalmat definiáljuk többféle módon, majd a netsemlegességgel kapcsolatos törvényhozói, internet- és tartalomszolgáltatói, valamint felhasználói kihívásokat, problémákat és válaszokat mutatjuk be. Számos szerző szerint az internet legnagyobb, immár tradicionális értéke a nyíltság, sokszínűség, tartalomgazdagság, tértől és időtől független társadalmi és perszonális kommunikációba való szabad belépés és a szabad verseny lehetősége. A netsemlegesség mellett és ellen felhozott érvek bemutatását is ezek a szempontok alapján tesszük. Kiemelt szerepet kap a netsemlegesség megsértésének kategorizálása is. Tanulmányunkban közlünk egy törvényalkotási kronológiát, mely az USA-ra, az EU-ra és Kelet-Ázsiára fókuszál, illetve ismertetjük a BEREC 2011-es felmérésének az EU-ban alkalmazott, internetszolgáltatói gyakorlatra vonatkozó eredményeit. A munkát az Internet.org kezdeményezést vizsgáló esettanulmány zárja, végül ezt követik a jövővel kapcsolatos kérdések, és néhány lehetséges válasz. --- Net neutrality - definitions and the standpoints of legislators, content providers, Internet service providers and users This article examines the topic of net neutrality. Firstly, it provides us with a theoretical insight and several definitions. Then it presents the issues and challenges legislators, ISP’s, content providers and users face. Several authors state that the biggest virtue and value of Internet lies in open access, diversity, richness of content, free competition, and low barrier entry for users in order to participate in personal social communication. Our presentation of arguments pro and cons net neutrality will be built on the basis of these considerations. Priority will be given to the introduction of several categories of net neutrality violations. In our paper we will present a legislative chronology in the topic focusing on USA, EU and Korea-Japan as well as the findings of the 2011 BEREC survey. Finally we examine the Internet.org project. In the conclusion, the article offers several more issues to be discussed and provides some possible answers.


2013 ◽  
Vol 543 ◽  
pp. 176-179 ◽  
Author(s):  
D.Q. Zhao ◽  
Xia Zhang ◽  
P. Liu ◽  
F. Yang ◽  
C. Lin ◽  
...  

In this work we studied the fabrication of a monolithic bimaterial micro-cantilever resonant IR sensor with on-chip drive circuits. The effects of high temperature process and stress induced performance degradation were investigated. The post-CMOS MEMS (micro electro mechanical system) fabrication process of this IR sensor is the focus of this paper, starting from theoretical analysis and simulation, and then moving to experimental verification. The capacitive cantilever structure was fabricated by surface micromachining method, and drive circuits were prepared by standard CMOS process. While the stress introduced by MEMS films, such as the tensile silicon nitride which works as a contact etch stopper layer for MOSFETs and releasing stop layer for the MEMS structure, increases the electron mobility of NMOS, PMOS hole mobility decreases. Moreover, the NMOS threshold voltage (Vth) shifts, and transconductance (Gm) degrades. An additional step of selective removing silicon nitride capping layer and polysilicon layer upon IC area were inserted into the standard CMOS process to lower the stress in MOSFET channel regions. Selective removing silicon nitride and polysilicon before annealing can void 77% Vth shift and 86% Gm loss.


2011 ◽  
Vol 64 (12) ◽  
pp. 1587 ◽  
Author(s):  
Ahmad Irfan ◽  
Abdullah G. Al-Sehemi ◽  
Shabbir Muhammad ◽  
Jingping Zhang

Theoretically calculated mobility has revealed that BDT is a hole transfer material, which is in good agreement with experimental investigations. The BDT, NHBDT, and OBDT are predicted to be hole transfer materials in the C2/c space group. Comparatively, hole mobility of BHBDT is 7 times while electron mobility is 20 times higher than the BDT. The packing effect for BDT and designed crystals was investigated by various space groups. Generally, mobility increases in BDT and its analogues by changing the packing from space group C2/c to space groups P1 or . In the designed ambipolar material, BHBDT hole mobility has been predicted 0.774 and 3.460 cm2 Vs–1 in space groups P1 and , which is 10 times and 48 times higher than BDT (0.075 and 0.072 cm2 Vs–1 in space groups P1 and ), respectively. Moreover, the BDT behaves as an electron transfer material by changing the packing from the C2/c space group to P1 and .


2021 ◽  
Author(s):  
Beatriz Matarranz ◽  
Goutam Ghosh ◽  
Ramesh Kandanelli ◽  
Angel Sampedro ◽  
Kalathil K. Kartha ◽  
...  

We unravel the relationship between conjugation length and self-assembly behaviour of oligophenyleneethynylenes (OPEs).


2021 ◽  
Author(s):  
Junli Chang ◽  
Liping Jiang ◽  
Guangzhao Wang ◽  
Yuhong Huang ◽  
Hong Chen

The optical absorption performance of the perovskite FAPbI3 in the visible-light range is significantly improved by constructing a CdS/FAPbI3 heterostructure.


Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 38-49
Author(s):  
Lakhdar Benhamed ◽  
Sidi Mohamed Mekelleche ◽  
Wafaa Benchouk

Experimentally, a reversal of chemoselectivity has been observed in catalyzed Diels–Alder reactions of α,β-unsaturated aldehydes (e.g., (2E)-but-2-enal) and ketones (e.g., 2-hexen-4-one) with cyclopentadiene. Indeed, using the triflimidic Brønsted acid Tf2NH as catalyst, the reaction gave a Diels–Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, the use of tris(pentafluorophenyl)borane B(C6F5)3 bulky Lewis acid as catalyst gave mainly the cycloadduct of α,β-unsaturated aldehyde as a major product. Our aim in the present work is to put in evidence the role of the catalyst in the reversal of the chemoselectivity of the catalyzed Diels–Alder reactions of (2E)-but-2-enal and 2-Hexen-4-one with cyclopentadiene. The calculations were performed at the ωB97XD/6-311G(d,p) level of theory and the solvent effects of dichloromethane were taken into account using the PCM solvation model. The obtained results are in good agreement with experimental outcomes.


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