http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, Sang Woo,Wang, Yang,You, Hoseon,Lee, Wonho,Michinobu, Tsuyoshi,Kim, Bumjoon J. American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.39
<P>Substitution of C atoms in a polymer backbone by N atoms allows for the facile tuning of the energy levels as well as the backbone conformation and packing structures of conjugated polymers. Herein, we report a series of three polymer acceptors (<I>P</I><SUB>A</SUB>s) with N atoms introduced at different positions of the backbone and investigate how these N atoms affect the device performances of all-polymer solar cells (all-PSCs). The three <I>P</I><SUB>A</SUB>s, namely, P(NDI2DT-BTT), P(NDI2DT-PTT), and P(NDI2DT-BTTz), are composed of naphthalenediimide (NDI)-based and benzothiadiazole (BT)-based derivatives (dithiophene-BT (BTT), dithiophene-thiadiazolepyridine (PTT), and dithiazole-BT (BTTz)). The PTT and BTTz units are synthesized by replacing the C atoms in BT and thiophene, respectively, with N atoms, which effectively tune the optical, electrochemical, and charge-transporting properties of the corresponding <I>P</I><SUB>A</SUB>s. The all-PSCs using poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl))benzo[1,2-<I>b</I>:4,5-<I>b</I>′]dithiophene)-<I>co</I>-(1,3-di(5-thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-<I>c</I>:4,5-<I>c</I>′]dithiophene-4,8-dione)] (PBDB-T) as a polymer donor and P(NDI2DT-PTT) as <I>P</I><SUB>A</SUB> exhibit a significantly enhanced power conversion efficiency (PCE) of 6.95%, whereas the all-PSCs based on the other <I>P</I><SUB>A</SUB>s show relatively lower PCEs (6.02% for PBDB-T:P(NDI2DT-BTT) and 1.43% for PBDB-T:P(NDI2DT-BTTz)). The high PCE of the PBDB-T:P(NDI2DT-PTT) device is due to the superior charge transfer and charge dissociation, resulting from the closely matched energy levels between PBDB-T and P(NDI2DT-PTT), as well as a more favorable bulk heterojunction morphology with improved miscibility. Importantly, the P(NDI2DT-PTT)-based all-PSC device shows improved air stability compared to the P(NDI2DT-BTT)-based device, which is most likely due to a decreased lowest unoccupied molecular orbital level of the <I>P</I><SUB>A</SUB>. Our findings suggest that the incorporation of N atoms into the <I>P</I><SUB>A</SUB>s is an effective strategy for improving the efficiency and stability of all-PSCs.</P> [FIG OMISSION]</BR>
Digital Memory Versatility of Fully π-Conjugated Donor–Acceptor Hybrid Polymers
Ko, Yong-Gi,Kim, Dong Min,Kim, Kyungtae,Jung, Sungmin,Wi, Dongwoo,Michinobu, Tsuyoshi,Ree, Moonhor American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.11
<P>The fully π-conjugated donor–acceptor hybrid polymers Fl-TPA, Fl-TPA-TCNE, and Fl-TPA-TCNQ, which are composed of fluorene (Fl), triphenylamine (TPA), dimethylphenylamine, alkyne, alkyne-tetracyanoethylene (TCNE) adduct, and alkyne-7,7,8,8-tetracyanoquinodimethane (TCNQ) adduct, were synthesized. These polymers are completely amorphous in the solid film state and thermally stable up to 291–409 °C. Their molecular orbital levels and band gaps vary with their compositions. The TCNE and TCNQ units, despite their electron-acceptor characteristics, were found to enhance the π-conjugation lengths of Fl-TPA-TCNE and Fl-TPA-TCNQ (i.e., to produce red shifts in their absorption spectra and significant reductions in their band gaps). These changes are reflected in the electrical digital memory behavior of the polymers. Moreover, the TCNE and TCNQ units were found to diversify the digital memory modes and to widen the active polymer layer thickness window. In devices with aluminum top and bottom electrodes, the Fl-TPA polymer exhibits stable unipolar permanent memory behavior with high reliability. The Fl-TPA-TCNE and Fl-TPA-TCNQ devices exhibit stable unipolar permanent memory behavior as well as dynamic random access memory behavior with excellent reliability. These polymer devices were found to operate by either hole injection or hole injection along with electron injection, depending on the polymer composition. Overall, this study demonstrated that the incorporation of π-conjugated cyano moieties, which control both the π-conjugation length and electron-accepting power, is a sound approach for the design and synthesis of high-performance digital memory polymers. The TCNE and TCNQ polymers synthesized in this study are highly suitable active materials for the low-cost mass production of high-performance, polarity-free, programmable, volatile, and permanent memory devices that can be operated with very low power consumption, high ON/OFF current ratios, and high reliability.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-11/am5013134/production/images/medium/am-2014-013134_0012.gif'></P>
New Fullerene-Based Polymers and Their Electrical Memory Characteristics
Ko, Yong-Gi,Hahm, Suk Gyu,Murata, Kimie,Kim, Young Yong,Ree, Brian J.,Song, Sungjin,Michinobu, Tsuyoshi,Ree, Moonhor American Chemical Society 2014 Macromolecules Vol.47 No.23
<P>Covalent incorporations into polymers of fullerene were achieved via the Cu(I)-catalyzed azide–alkyne click polymerizations of a fullerene derivative monomer functionalized with 5-(trimethylsilyl)pent-4-yn-1-yl groups and a comonomer functionalized with azidomethyl groups, producing the novel fullerene polymers P1-<I>C</I><SUB>60</SUB> and P2-<I>C</I><SUB>60</SUB>. Despite their extremely high fullerene loading levels, the polymers were soluble in common organic solvents and exhibited no aggregation of fullerene units in films. Moreover, devices containing these fullerene polymers were easily fabricated with common coating processes that exhibit excellent unipolar and bipolar flash memory characteristics as well as unipolar permanent memory characteristics, with high ON/OFF current ratios, long retention times, and low power consumption. These electrical switching behaviors were favorably operated by electron injection. Overall, these devices are the first n-type bipolar and unipolar digital polymer memory devices which can be operated in flash and write-once-read-many-times modes.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2014/mamobx.2014.47.issue-23/ma5021402/production/images/medium/ma-2014-021402_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma5021402'>ACS Electronic Supporting Info</A></P>
Electrical Memory Characteristics of Nitrogen-Linked Poly(2,7-carbazole)s
Hahm, Suk Gyu,Lee, Taek Joon,Kim, Dong Min,Kwon, Wonsang,Ko, Yong-Gi,Michinobu, Tsuyoshi,Ree, Moonhor American Chemical Society 2011 The Journal of Physical Chemistry Part C Vol. No.
<P>We studied the electrical memory characteristics of the following nitrogen-linked poly(2,7-carbazole)s: poly(9-hexadecyl-2,7-carbazole-<I>alt</I>-<I>N</I>,<I>N</I>-(4-hexadecyloxy)aniline), poly(9-hexadecyl-<I>N</I>,<I>N′</I>-diphenylcarbazole-2,7-diamine-<I>alt</I>-1,3-benzene), and poly(9-hexadecyl-<I>N</I>,<I>N′</I>-diphenylcarbazole-2,7-diamine-<I>alt</I>-4,4<I>′</I>-biphenyl). These polymers are amorphous; however, in thin films, they are slightly oriented in the film plane. All polymers in devices with aluminum top and bottom electrodes were found to exhibit similar dynamic random access memory (DRAM) behaviors without polarity. They are operable with a low voltage (less than ±3 V) and a high ON/OFF current ratio (10<SUP>5</SUP>–10<SUP>9</SUP>, depending on the polymer) over the thickness range 8–60 nm. The memory behaviors were found to be governed by space-charge limited conduction and local filament formation. These memory characteristics might originate from the electron-donating carbazole and triphenylamino units in the polymer backbones, which act as charge-trapping sites but have weak electric polarization because of the absence of counterparts. Overall, these polymers are suitable active materials for the mass production at low cost of high-performance, programmable volatile memory devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2011/jpccck.2011.115.issue-44/jp207211e/production/images/medium/jp-2011-07211e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp207211e'>ACS Electronic Supporting Info</A></P>