Hole transport materials for high hole mobility by using pyrene derivatives

정숙희,이준엽 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

We designed and synthesized hole-type materials for high hole mobility using pyrene moiety. The hole transport material was synthesized by two-step and the reaction yield was around 75.0%. The material’s the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was estimated by measurement of ionization potential and electron affinity. HOMO of material was calculated as -5.63 eV and LUMO of material was calculated as -3.21 eV. And this material was evaluated by fabricating single layer device. Device property result showed that evaluated material had high hole mobility. This work demonstrated that newly synthesized hole type pyrene derivative was effective for hole transport layer.

Side substitution on benzothiadiazole-based hole transporting materials with a D–A–D molecular configuration for efficient perovskite solar cells

Yang Jixin,Hu Weixia 한국물리학회 2023 Current Applied Physics Vol.45 No.-

A series of benzothiadiazole-based Donor-Acceptor-Donor (D-A-D) typed hole-transporting materials (HTMs) are designed through introducing electron-withdrawing fluorine group and electron-donating alkoxy group into the core of benzothiadiazole (BT). The energy level alignment, electronic properties, absorption, and hole transport properties of these materials are explored comprehensively using First-principle calculations. As compared with the reference molecule BT, three other substituted molecules have lower HOMO energy levels and lower reorganization energy. Especially, two fluorine substituted hole-transporting materials BT-1F and BT-2F possess planar molecular configuration, suitable energy level, indicating that fluorine substitution is beneficial to the increase of open circuit voltage of device. Moreover, the hole transporting mobility, solubility and stability of all designed molecules are also estimated, which are important items to determine the cost and performance in real application of solar cells. Calculated results show that hole mobility of monofluorinated molecule BT-1F displays relatively higher hole mobility owing to efficient intermolecular interactions. Therefore, molecule BT-1F is likely to be highly efficient HTMs because of its excellent hole mobility and solubility. The present work demonstrates that fluorination engineering on core acceptors in D-A-D typed HTMs is an effective strategy to tune the photovoltaic performance of perovskite solar cells.

Enhancement in the hole mobility of perovskite solar cells by incorporating an additive to the hole transporting layer

여인영,전유성,황태원,박성주,배재호,한윤수 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

We have investigated effects of a low-molecular-weight hole-transporting material (LHTM) as an additive of a polymeric HTM (PHTM) on the photovoltaic performance of perovskite solar cells. A device with a blend film of PHTM:LHTM showed an enhancement in open-circuit voltage, short-circuit current and fill factor, resulting in a 9% increase in power conversion efficiency, compared to that of the control device with the pristine PHTM layer. This enhanced performance was attributed to an increase in the hole mobility and a decrease in the charge recombination of the solar cell with the PHTM:LHTM blend film.

Enhanced performance of perovskite solar cells by incorporation of a triphenylamine derivative into hole-transporting poly(3-hexylthiophene) layers

Kim, Ji Young,Kwak, Giseop,Choi, Yong Chan,Kim, Dae-Hwan,Han, Yoon Soo THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.73 No.-

<P><B>Abstract</B></P> <P>A 4,4′,4″-tris[phenyl(<I>m</I>-tolyl)amino]triphenylamine (<I>m-MTDATA</I>) was applied as an additive to hole-transporting poly(3-hexylthiophene) [P3HT] layers in perovskite solar cells. The incorporation of 0.5wt% <I>m-MTDATA</I> to the P3HT layer led to an increased power conversion efficiency of 9.53%, due to an enhancement in the short circuit current, open-circuit voltage and fill factor, compared with that (8.76%) of the control cell without the additive. This enhanced performance was attributed to an increase in the hole mobility and a decrease in the charge recombination of the device with the P3HT:<I>m-MTDATA</I> blend film, compared to those of the control device with the pristine P3HT film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance of PeSCs was increased by <I>m-MTDATA</I> incorporation to P3HT layer. </LI> <LI> <I>m-MTDATA</I> in P3HT played a role of enhancing hole mobility and reducing charge recombination. </LI> <LI> Enhanced hole mobility and reduced charge recombination led to an increase in <I>J<SUB>sc</SUB> </I>, <I>V<SUB>oc</SUB> </I> and <I>FF</I>. </LI> <LI> <I>m-MTDATA</I> incorporation in P3HT is a good strategy to improve performance of PeSCs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>4,4′,4″-Tris[phenyl(<I>m</I>-tolyl)amino]triphenylamine (<I>m-MTDATA</I>) was applied as an additive to hole-transporting poly(3-hexylthiophene) [P3HT] layers in perovskite solar cells. The incorporation of 0.5wt% <I>m-MTDATA</I> into the P3HT layers led to an increased power conversion efficiency owing to the enhancement in the short-circuit current, the open-circuit voltage and the fill factor, compared with that of the control cell without the additive. It was found that the improved efficiency was attributed to an increase in the hole mobility and a reduction in the charge recombination.</P> <P>[DISPLAY OMISSION]</P>

Effect of molecular weight of copolymers containing carbazole groups on the performance of the solid-state dye-sensitive solar cell

( Nguyen Van Nga ),전솔민,정수란,권영환 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In this study, the poly[N-(2-ethylhexyl)-3,6-carbazole-alt-aniline] (PI) and poly{bis-[6-bromo-N-(2-ethylhexyl)-carbazole-3-yl]-alt-aniline} (PII) were synthesized as polymer containing carbazole groups with different molecular weights. The PI and PII were applied as a new hole transport material (HTM) to characterize the effects of molecular weight on performance and hole mobility properties in the device. The PI and PII were synthesized via 3,6-dibromocarbazole, Bis[6-bromo-N- (2-ethylhexyl)-carbazole-3-yl], and aniline. These polymers were fractionated to separate high and low molecular weight. Their properties such as thermal, optical, electrochemical and hole mobility properties were characterized. The performance of the polymers was characterized by the solar simulation machine. The PI and PII are successfully synthesized by Pd-catalyzed polycondensation reaction. The polymers perform good material as HTM layer for solid-state sensitized solar cell with high hole mobility.

Effects of π-conjugation on the charge-transport properties of hole-transporting materials featuring diphenylamine- π-quinacridone for perovskite solar cells: A theoretical study

Rashid Md Al Mamunur,Kim Junkyu,Long Dang Xuan,Kwak Kyungwon,Hong Jongin 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.5

Density functional theory (DFT), time-dependent DFT, and Marcus theory were used to probe the optoelectronic and charge-transport properties of compounds obtained by inserting long-chain aliphatic alkenes or condensed aromatic rings between the planar quinacridone core and the terminal donor diphenylamine moiety of a reference hole-transporting material (HTM). Compared to the reference HTM, its newly designed derivatives showed lower-lying highest occupied molecular orbitals that were well matched in energy with the valence band maximum of a representative perovskite absorber. HTMs obtained via the insertion of condensed aromatic rings showed higher hole mobilities than those obtained via the insertion of aliphatic alkenes. Overall, hole mobility was mainly influenced by the charge-transfer integral, while other factors, such as the hole reorganization energy, hole hopping rate, and centroid distance, had only minor effects.

A Mobile Robot Based on Slip Compensating Algorithm for Cleaning of Stud Holes at Reactor Vessel in NPP

김동일,문영준 한국압력기기공학회 2020 한국압력기기공학회 논문집 Vol.16 No.1

The APR1400 reactor stud holes can be stuck due to high temperatures, high pressure, prolonged engagement, and load changes according to pressure changes in the reactor. Threaded surfaces of a stud hole should be cleaned for the sealing of pressure in reactor vessel by removing any foreign materials which may exist in the stud holes. Human workers can access to the stud hole for the cleaning of stud holes manually, but the radiation exposure of human workers is increased. Robot is an effective way to work in hazardous area. So we introduced robot for the cleaning of stud holes. Localization of mobile robots is generally based on odometry, but with increased mileage, position errors can be accumulated. In order to eliminate cumulative error and to ensure stability of its driving, laser sensors and new control algorithm were utilized. The distance between the robot and the wall was measured by laser sensors, and the control algorithm was implemented so as to travel the desired trajectory by using the measured values from sensors. The performance of driving and hole sensing were verified through field application, and mobile robot was confirmed to be applicable to the APR 1400 NPP.

Well-balanced carrier mobilities in ambipolar transistors based on a low band gap small molecule semiconductors

김민제,( Min Woo Jung ),( Woonggi Kang ),( Youngwoon Yoon ),( Gukil An ),( Hyunjung Kim ),( Hae Jung Son ),( Bongsoo Kim ),( Jeong Ho Cho ) 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

We synthesized a solution-processable low band gap small molecule, Si1TDPP-EE-COC6, for use as a semiconducting channel material in organic thin film transistors (OTFTs). The Si1TDPP-EE-COC6 structure consisted of electron-rich thiophene-dithienosilole-thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) units. The electrical properties of the resulting OTFTs were systematically investigated as a function of the thermal annealing conditions. The hole and electron mobilities of as-spun Si1TDPP-EE-COC6 were 3.3 × 10^-4 and 1.7 × 10^-4 cm²/(Vs), respectively. The carrier mobilities increased significantly upon thermal annealing at 150°C, yielding a hole mobility of 0.003 cm²/(Vs) and an electron mobility of 0.002 cm²/(Vs). The perfor mance enhancement upon thermal annealing was strongly associated with the formation of a layered edge-on structure and a reduction in the π-π intermolecular spacing, as revealed by grazing incidence X-ray diffraction and atomic force microscopy measurements. Importantly, the use of atomically thin CVD-grown single layer graphene (SLG) source/drain electrodes further increased the carrier mobilities. The SLG OTFTs prepared using the 150°C-annealed Si1TDPP-EE-COC6 exhibited a hole mobility of 0.011 cm²/(Vs) and an electron mobility of 0.015 cm²/(Vs), which are among the highest values yet reported for DPP-based small molecules. The improved electrical performances of the SLG OTFTs originated from the step-less flat surface and the wellaligned energy levels of the SLG electrodes in contact with the Si1 TDPP-EE-COC6 molecules. The use of CVD-grown SLG electrodes provided a facile method for improving the OTFT performance based on DPP-based small molecule semiconductors.

A multi-subband Monte Carlo study on dominance of scattering mechanisms over carrier transport in sub-10-nm Si nanowire FETs

Springer US 2016 NANOSCALE RESEARCH LETTERS Vol.11 No.1

<P>Dominance of various scattering mechanisms in determination of the carrier mobility is examined for silicon (Si) nanowires of sub-10-nm cross-sections. With a focus on <I>p</I>-type channels, the steady-state hole mobility is studied with multi-subband Monte Carlo simulations to consider quantum effects in nanoscale channels. Electronic structures of gate-all-around nanowires are described with a 6-band <I>k</I> · <I>p</I> model. Channel bandstructures and electrostatics under gate biases are determined self-consistently with Schrödinger-Poisson simulations. Modeling results not only indicate that the hole mobility is severely degraded as channels have smaller cross-sections and are inverted more strongly but also confirm that the surface roughness scattering degrades the mobility more severely than the phonon scattering does. The surface roughness scattering affects carrier transport more strongly in narrower channels, showing ∼90 % dominance in determination of the mobility. At the same channel population, [110] channels suffer from the surface roughness scattering more severely than [100] channels do, due to the stronger corner effect and larger population of carriers residing near channel surfaces. With a sound theoretical framework coupled to the spatial distribution of channel carriers, this work may present a useful guideline for understanding hole transport in ultra-narrow Si nanowires.</P>

Carrier Lifetime Extension via the Incorporation of Robust Hole/Electron Blocking Layers in Bulk Heterojunction Polymer Solar Cells

Yoon, Youngwoon,Kim, Hyeong Jun,Cho, Chul-Hee,Kim, Seulki,Son, Hae Jung,Ko, Min-Jae,Kim, Honggon,Lee, Doh-Kwon,Kim, Jin Young,Lee, Wonmok,Kim, Bumjoon J.,Kim, BongSoo American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.1

<P>We report the achievement of a power conversion efficiency (PCE) improvement in P3HT:PCBM-based bulk-heterojunction type polymer solar cells using photocrosslinked P3HT (c-P3HT) as the electron blocking/hole extraction layer and titanium oxide nanoparticles (TiO<SUB>2</SUB>) as the hole blocking/electron extraction layer. Devices prepared with a 20 nm thick c-P3HT layer showed an improved PCE of 3.4% compared to devices prepared without the c-P3HT layer (PCE = 3.0%). This improvement was attributed to an extension in the carrier lifetime and an enhancement in the carrier mobility. The incorporation of the c-P3HT layer lengthened (by more than a factor of 2) the carrier lifetime and increased (by a factor of 5) the hole mobility. These results suggest that the c-P3HT layer not only prevented non-geminate recombination but it also improved carrier transport. The PCE was further improved to 4.0% through the insertion of a TiO<SUB>2</SUB> layer that acted as an effective hole-blocking layer at the interface between the photoactive layer and the cathode. This work demonstrates that the incorporation of solution-processable hole and electron blocking/extraction layers offers an effective means for preventing nongeminate recombination at the interfaces between a photoactive layer and an electrode in bulk-heterojunction-type polymer solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-1/am404381e/production/images/medium/am-2013-04381e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am404381e'>ACS Electronic Supporting Info</A></P>