A NOVEL METHOD AND PROCEDURE FOR ON-LINE MEASUREMENT OF FLUID PROPERTIES FOR CONTROL AND OPTIMIZATION

Azmi Kaya,Marion A Keyes 제어로봇시스템학회 1989 제어로봇시스템학회 국내학술대회 논문집 Vol.1989 No.10

Improved performance of colloidal quantum dot solar cells using high-electric-dipole self-assembled layers

Azmi, Randi,Nam, So Youn,Sinaga, Septy,Oh, Seung-Hwan,Ahn, Tae Kyu,Yoon, Sung Cheol,Jung, In Hwan,Jang, Sung-Yeon Elsevier 2017 Nano energy Vol.39 No.-

<P><B>Abstract</B></P> <P>High performance colloidal quantum dot (CQD) solar cells were developed by modifying ZnO electron accepting layers (EALs) using self-assembled monolayers (SAMs) of highly polar molecules. A high molecular dipole moment of −10.07D was achieved by conjugating a strong electron donor, julolidine, to an electron acceptor, a cyanoacetic acid unit, through a thiophene moiety. The energetic properties of ZnO EALs were manipulated with respect to the dipole moment of the modifying molecules. The built-in potential (<I>V</I> <SUB>bi</SUB>) and internal electric field (<I>E</I> <SUB>int</SUB>) of CQD solar cells could thereby be tuned. The power conversion efficiency (PCE) of the SAM modified devices was improved from 3.7% to 12.9% relative to the unmodified devices as a function of molecular dipole moments (from −5.13D to −10.07D). All figures-of-merit of solar cells were improved simultaneously by SAM modification due to enhanced <I>V</I> <SUB>bi</SUB>, <I>E</I> <SUB>int</SUB>, and charge collection efficiency. The PCE of the highly polar molecule modified devices reached 10.89% with a <I>V</I> <SUB>OC</SUB> of 0.689V, whereas that of the unmodified devices was 9.65% with a <I>V</I> <SUB>OC</SUB> of 0.659V. Notably, the remarkably low energy loss of 0.433eV is achieved in the SAM modified devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High efficiency colloidal quantum dot solar cells were developed using highly polar SAM modified ZnO electron accepting layers. </LI> <LI> Synthesized novel self-assembling highly polar molecules for electric dipole layer (EDL). </LI> <LI> The solar cell performance was improved by the modification due to enhanced internal electric field and charge collection efficiency. </LI> <LI> The power conversion efficiency of 10.89% with energy loss of 0.433eV was achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>High efficiency colloidal quantum dot solar cells were developed using highly polar SAM modified ZnO electron accepting layers. The solar cell performance was improved by the modification due to enhanced internal electric field and charge collection efficiency. The power conversion efficiency of 10.89% with energy loss of 0.433eV was achieved.</P> <P>[DISPLAY OMISSION]</P>

High-performance dopant-free conjugated small molecule-based hole-transport materials for perovskite solar cells

Azmi, Randi,Nam, So Youn,Sinaga, Septy,Akbar, Zico Alaia,Lee, Chang-Lyoul,Yoon, Sung Cheol,Jung, In Hwan,Jang, Sung-Yeon Elsevier 2018 Nano energy Vol.44 No.-

<P><B>Abstract</B></P> <P>Hole-transport materials are a crucial element influencing the efficiency, hysteresis, and stability of perovskite solar cells (PSCs). Current state-of-the-art hole-transport materials require additional oxidizing dopants to achieve sufficient hole-transport properties; however, these dopants are environmentally harmful while also deteriorating the stability of PSCs. The development of high-performance dopant-free hole-transport materials is an important goal in the field of PSCs. In this work, we developed novel conjugated small-molecule based dopant-free hole-transport materials for PSCs containing di(1-benzothieno)[3,2-b:2′,3′-d]pyrrole (DBTP) as a core unit. These small molecule hole-transport materials achieved higher hole mobility and interfacial charge transfer rates than optimally doped spiro-OMeTAD, the current-state-of-the-art hole-transport material. A low-temperature PSC device using a dopant-free small molecule hole-transport material displayed a PCE of 18.09% with negligible hysteresis, higher than a device using doped spiro-OMeTAD (17.82%). Notably, the hydrophobic nature of our dopant-free small molecule hole-transport materials afforded excellent air-storage stability of low-temperature PSCs (81% retention after 33 days), whereas the doped spiro-OMeTAD based PSCs rapidly degraded under identical conditions (< 1% retention after 33 days).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel dopant-free hole-transport-materials for perovskite solar cells were developed. </LI> <LI> The face-on orientation enabled sufficiently high hole mobility without dopants. </LI> <LI> Low-temperature PSCs based on the dopant-free HTMs showed the efficiency of 18.09%. </LI> <LI> The dopant-free HTMs acted as passivation layers, providing excellent air stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>High-performance dopant-free small molecule hole-transport-materials (SM-HTMs) for perovskite solar cells (PSCs) are developed. The SM-HTMs possess appropriate energy levels with sufficient hole mobility to function as efficient HTM for PSCs without additional dopants. A low-temperature PSC (L-PSC) device using a dopant-free SM-HTM displayed a PCE of 18.09% with high air-storage stability, which is superior to a device using doped spiro-OMeTAD.</P> <P>[DISPLAY OMISSION]</P>

Performance Improvement of p-Channel Tin Monoxide Transistors With a Solution-Processed Zirconium Oxide Gate Dielectric

Azmi, Azida,Lee, Jiwon,Gim, Tae Jung,Choi, Rino,Jeong, Jae Kyeong IEEE 2017 IEEE electron device letters Vol.38 No.11

<P>This letter reports the fabrication of p-channel tin monoxide (SnO) thin-film transistors (TFTs) with a highpermittivity zirconiumoxide (ZrO2) gate insulatorfilm, which were prepared by a low-cost spin-cast method. The spincast ZrO2 dielectrics exhibit a low leakage current density of 4.5x10(-8) A/cm(2) at 1 MV/cm. Introducing the ZrO2 dielectric in top-typeSnOTFTs allows for a reduction in the driving gate voltage range from 80 to 10 V, ascomparedwith devices with a thermal SiO2 gate insulator. Additionally, a high fieldeffect mobility of 2.5 cm(2)/Vs and an ION/OFF of 3 x10(3) were preserved.</P>

Dynamic analysis of concrete column reinforced with Sio₂ nanoparticles subjected to blast load

Azmi, Masoud,Kolahchi, Reza,Bidgoli, Mahmood Rabani Techno-Press 2019 Advances in concrete construction Vol.7 No.1

The project focuses on the dynamic analysis of concrete beams reinforced with silica-nanoparticles under blast loading. The structure is located at two boundary conditions. The equivalent composite properties are determined using Mori-Tanak model. The structure is simulated with sinusoidal shear deformation theory. Employing nonlinear strains-displacements, stress-strain, the energy equations of beam were obtained and using Hamilton's principal, the governing equations were derived. Using differential quadrature methods (DQM) and Newmark method, the dynamic deflection of the structure is obtained. The influences of volume percent and agglomeration of silica nanoparticles, geometrical parameters of beam, boundary condition and blast load on the dynamic deflection were investigated. Results showed that with increasing volume percent of silica nanoparticles, the dynamic deflection decreases.

Study of Dielectric Properties of a Potential RBD Palm Oil and RBD Soybean Oil Mixture as Insulating Liquid in Transformer

Azmi, Kiasatina,Ahmad, Azmier,Kamarol, Mohamad The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

This paper reported the experimental result of dielectric properties of Refined, Bleached and Deodorized Palm Oil (RBDPO) combined with 0-50% of Refined, Bleached and Deodorized Soybean Oil (RBDSO). The dielectric strength and relative permittivity of RBDPO/RBDSO was higher compared to mineral oil at all ranges of ratios and temperatures which indicated a positive sign for its possible use as insulating liquid in a transformer. All ratios of the RBDPO/RBDSO mixture also demonstrated lower dissipation factor compared to mineral oil at 40℃, 70℃ and 90℃. Apart from that, the kinematic viscosity for the oil mixtures shown exceeded the IEC 60296 as well as the mineral oil results. 70%RBDPO/30%RBDSO mixture ratio was chosen as the best mixing percentage after comparison was made with the mineral oil and IEC 60296 standard where the mixture accumulated the most satisfactory of dielectric properties hence making it as the potential candidate for palm and soybean-based transformer oil.

A Novel Method and Procedure for On-Line Measurement of Fluid Properties For Control and Optimization

Azmi Kaya,Marion A. Keyes 대한전자공학회 1989 대한전자공학회 학술대회 Vol.1989 No.01

Performance Improvement in Low-Temperature-Processed Perovskite Solar Cells by Molecular Engineering of Porphyrin-Based Hole Transport Materials

Azmi, Randi,Lee, Un-Hak,Wibowo, Febrian Tri Adhi,Eom, Seung Hun,Yoon, Sung Cheol,Jang, Sung-Yeon,Jung, In Hwan American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.41

<P>Porphyrin derivatives have recently emerged as hole transport layers (HTLs) because of their electron-rich characteristics. Although several successes with porphyrin-based HTLs have been recently reported, achieving excellent solar cell performance, the chances to improve this further by molecular engineering are still open. In this work, Zn porphyrin (P<SUB>Zn</SUB>)-based HTLs were developed by conjugating fluorinated triphenylamine (FTPA) wings at the perimeter of the P<SUB>Zn</SUB> core for low-temperature perovskite solar cells (L-PSCs). The fluorinated P<SUB>Zn</SUB>-HTLs (P<SUB>Zn</SUB>-2FTPA and P<SUB>Zn</SUB>-3FTPA) exhibited superior HTL properties compared to the nonfluorinated one (P<SUB>Zn</SUB>-TPA). Moreover, their deeper highest occupied molecular orbital energy levels were beneficial for boosting open-circuit voltages, and their enhanced face-on stacking improved the hole transport properties. The L-PSC using P<SUB>Zn</SUB>-2FTPA achieved the highest performance of 18.85%. Thus far, this result is one of the highest reported power conversion efficiencies among the PSCs using porphyrin-based HTLs.</P> [FIG OMISSION]</BR>

High-Efficiency Low-Temperature ZnO Based Perovskite Solar Cells Based on Highly Polar, Nonwetting Self-Assembled Molecular Layers

Azmi, Randi,Hadmojo, Wisnu Tantyo,Sinaga, Septy,Lee, Chang-Lyoul,Yoon, Sung Cheol,Jung, In Hwan,Jang, Sung-Yeon Wiley-VCH 2018 ADVANCED ENERGY MATERIALS Vol.8 No.5

<P>Herein, this study reports high-efficiency, low-temperature ZnO based planar perovskite solar cells (PSCs) with state-of-the-art performance. They are achieved via a strategy that combines dual-functional self-assembled monolayer (SAM) modification of ZnO electron accepting layers (EALs) with sequential deposition of perovskite active layers. The SAMs, constructed from newly synthesized molecules with high dipole moments, act both as excellent surface wetting control layers and as electric dipole layers for ZnO-EALs. The insertion of SAMs improves the quality of PbI2 layers and final perovskite layers during sequential deposition, while charge extraction is enhanced via electric dipole effects. Leveraged by SAM modification, our low-temperature ZnO based PSCs achieve an unprecedentedly high power conversion efficiency of 18.82% with a V-OC of 1.13 V, a J(SC) of 21.72 mA cm(-2), and a FF of 0.76. The strategy used in this study can be further developed to produce additional performance enhancements or fabrication temperature reductions.</P>

Simultaneous Improvement in Efficiency and Stability of Low-Temperature-Processed Perovskite Solar Cells by Interfacial Control

Azmi, Randi,Lee, Chang-Lyoul,Jung, In Hwan,Jang, Sung-Yeon Wiley-VCH 2018 ADVANCED ENERGY MATERIALS Vol.8 No.14

<P>In most current state-of-the-art perovskite solar cells (PSCs), high-temperature (approximate to 500 degrees C)-sintered metal oxides are employed as electron-transporting layers (ETLs). To lower the device processing temperature, the development of low-temperature-processable ETL materials (such as solution-processed ZnO) has received growing attention. However, thus far, the use of solutionprocessed ZnO is limited because the reverse decomposition reaction that occurs at ZnO/perovskite interfaces significantly degrades the charge collection and stability of PSCs. In this work, the reverse decomposition reaction is successfully retarded by sulfur passivation of solution-processed ZnO. The sulfur passivation of ZnO by a simple chemical means, efficiently reduces the oxygen-deficient defects and surface oxygen-containing groups, thus effectively preventing reverse decomposition reactions during and after formation of the perovskite active layers. Using the low-temperature-processed sulfurpassivated ZnO (ZnO-S), perovskite layers with higher crystallinity and larger grain size are obtained, while the charge extraction at the ZnO/perovskite interface is significantly improved. As a result, the ZnO-S-based PSCs achieve substantially improved power-conversion-efficiency (PCE) (19.65%) and long-term air-storage stability (90% retention after 40 d) compared with pristine ZnO-based PSCs (16.51% and 1% retention after 40 d). Notably, the PCE achieved is the highest recorded (19.65%) for low-temperature ZnObased PSCs.</P>