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21 results on '"Khan, Motiur Rahman"'

3. Bulk Incorporation with 4‐Methylphenethylammonium Chloride for Efficient and Stable Methylammonium‐Free Perovskite and Perovskite‐Silicon Tandem Solar Cells

Author

Duong, The, primary, Nguyen, Thuan, additional, Huang, Keqing, additional, Pham, Huyen, additional, Adhikari, Sunita Gautam, additional, Khan, Motiur Rahman, additional, Duan, Leiping, additional, Liang, Wensheng, additional, Fong, Kean Chern, additional, Shen, Heping, additional, Bui, Anh Dinh, additional, Mayon, Azul Osorio, additional, Truong, Thien, additional, Tabi, Grace, additional, Ahmad, Viqar, additional, Surve, Sachin, additional, Tong, Jingnan, additional, Kho, Teng, additional, Tran‐Phu, Thanh, additional, Lu, Teng, additional, Zheng, Jianghui, additional, Paetzold, Ulrich W., additional, Lemmer, Uli, additional, Baillie, Anita Ho, additional, Liu, Yun, additional, Andersson, Gunther, additional, White, Thomas, additional, Weber, Klaus, additional, and Catchpole, Kylie, additional

Published
2023
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4. Interface Passivation Schemes for Highly Efficient Inverted Perovskite Solar Cells and Two-Terminal perovskite/c-Si and perovskite/CI(G)S tandem solar cells

Author

Fassl, Paul, primary, Gharibzadeh, Saba, additional, Ruiz-Preciado, Marco A., additional, Khan, Motiur Rahman, additional, Farag, Ahmed, additional, Moghadamzadeh, Somayeh, additional, Klein, Christoph, additional, Hossain, Ihteaz M., additional, Singh, Roja, additional, and Paetzold, Ulrich W., additional

Published
2022
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6. Optimization of SnO2 electron transport layer for efficient planar perovskite solar cells with very low hysteresis

Author

Eliwi, Abed Alrhman, primary, Malekshahi Byranvand, Mahdi, additional, Fassl, Paul, additional, Khan, Motiur Rahman, additional, Hossain, Ihteaz Muhaimeen, additional, Frericks, Markus, additional, Ternes, Simon, additional, Abzieher, Tobias, additional, Schwenzer, Jonas A., additional, Mayer, Thomas, additional, Hofmann, Jan P., additional, Richards, Bryce S., additional, Lemmer, Uli, additional, Saliba, Michael, additional, and Paetzold, Ulrich W., additional

Published
2022
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7. Optimization of SnO$_{2}$ electron transport layer for efficient planar perovskite solar cells with very low hysteresis†

Author

Eliwi, Abed Alrhman, Malekshahi Byranvand, Mahdi, Fassl, Paul, Khan, Motiur Rahman, Hossain, Ihteaz Muhaimeen, Frericks, Markus, Ternes, Simon, Abzieher, Tobias, Schwenzer, Jonas A., Mayer, Thomas, Hofmann, Jan P., Richards, Bryce S., Lemmer, Uli, Saliba, Michael, and Paetzold, Ulrich W.

Subjects
ddc:620, Engineering & allied operations
Abstract

Nanostructured tin oxide (SnO$_{2}$) is a very promising electron transport layer (ETL) for perovskite solar cells (PSCs) that allows low-temperature processing in the planar n–i–p architecture. However, minimizing current–voltage (J–V) hysteresis and optimizing charge extraction for PSCs in this architecture remains a challenge. In response to this, we study and optimize different types of single- and bilayer SnO$_{2}$ ETLs. Detailed characterization of the optoelectronic properties reveals that a bilayer ETL composed of lithium (Li)-doped compact SnO$_{2}$ (c(Li)-SnO$_{2}$) at the bottom and potassium-capped SnO$_{2}$ nanoparticle layers (NP-SnO$_{2}$) at the top enhances the electron extraction and charge transport properties of PSCs and reduces the degree of ion migration. This results in an improved PCE and a strongly reduced J–V hysteresis for PSCs with a bilayer c(Li)-NP-SnO$_{2}$ ETL as compared to reference PSCs with a single-layer or undoped bilayer ETL. The champion PSC with c(Li)-NP-SnO$_{2}$ ETL shows a high stabilized PCE of up to 18.5% compared to 15.7%, 12.5% and 16.3% for PSCs with c-SnO$_{2}$, c(Li)-SnO$_{2}$ and c-NP-SnO$_{2}$ as ETL, respectively.

Published
2021

8. Dipolar doping of organic semiconductors to enhance carrier injection

Author

Hofmann, Alexander J.L., Züfle, Simon, Shimizu, Kohei, Schmid, Markus, Wessels, Vivien, Jäger, Lars, Altazin, Stéphane, Ikegami, Keitaro, Khan, Motiur Rahman, Neher, Dieter, Ishii, Hisao, Ruhstaller, Beat, Brütting, Wolfgang, Hofmann, Alexander J.L., Züfle, Simon, Shimizu, Kohei, Schmid, Markus, Wessels, Vivien, Jäger, Lars, Altazin, Stéphane, Ikegami, Keitaro, Khan, Motiur Rahman, Neher, Dieter, Ishii, Hisao, Ruhstaller, Beat, and Brütting, Wolfgang

Abstract

If not oriented perfectly isotropically, the strong dipole moment of polar organic semiconductor materials such as tris-(8-hydroxyquinolate)aluminum (Alq3) will lead to the buildup of a giant surface potential (GSP) and thus to a macroscopic dielectric polarization of the organic film. Despite this having been a known fact for years, the implications of such high potentials within an organic layer stack have only been studied recently. In this work, the influence of the GSP on hole injection into organic layers is investigated. Therefore, we apply a concept called dipolar doping to devices consisting of the prototypical organic materials N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) as nonpolar host and Alq3 as dipolar dopant with different mixing ratios to tune the GSP. The mixtures are investigated in single-layer monopolar devices as well as bilayer metal/insulator/semiconductor structures. Characterization is done electrically using current-voltage (I-V) characteristics, impedance spectroscopy, and charge extraction by linearly increasing voltage and time of flight, as well as with ultraviolet photoelectron spectroscopy. We find a maximum in device performance for moderate to low doping concentrations of the polar species in the host. The observed behavior can be described on the basis of the Schottky effect for image-force barrier lowering, if the changes in the interface dipole, the carrier mobility, and the GSP induced by dipolar doping are taken into account.

Published
2020

10. Two birds with one stone: dual grain-boundary and interface passivation enables >22% efficient inverted methylammonium-free perovskite solar cells

Author

Gharibzadeh, Saba, primary, Fassl, Paul, additional, Hossain, Ihteaz M., additional, Rohrbeck, Pascal, additional, Frericks, Markus, additional, Schmidt, Moritz, additional, Duong, The, additional, Khan, Motiur Rahman, additional, Abzieher, Tobias, additional, Nejand, Bahram Abdollahi, additional, Schackmar, Fabian, additional, Almora, Osbel, additional, Feeney, Thomas, additional, Singh, Roja, additional, Fuchs, Dirk, additional, Lemmer, Uli, additional, Hofmann, Jan P., additional, Weber, Stefan A. L., additional, and Paetzold, Ulrich W., additional

Published
2021
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11. High Efficiency Perovskite‐Silicon Tandem Solar Cells: Effect of Surface Coating versus Bulk Incorporation of 2D Perovskite

Author

Duong, The, primary, Pham, Huyen, additional, Kho, Teng Choon, additional, Phang, Pheng, additional, Fong, Kean Chern, additional, Yan, Di, additional, Yin, Yanting, additional, Peng, Jun, additional, Mahmud, Md Arafat, additional, Gharibzadeh, Saba, additional, Nejand, Bahram Abdollahi, additional, Hossain, Ihteaz M., additional, Khan, Motiur Rahman, additional, Mozaffari, Naeimeh, additional, Wu, YiLiang, additional, Shen, Heping, additional, Zheng, Jianghui, additional, Mai, Haoxin, additional, Liang, Wensheng, additional, Samundsett, Chris, additional, Stocks, Matthew, additional, McIntosh, Keith, additional, Andersson, Gunther G., additional, Lemmer, Uli, additional, Richards, Bryce S., additional, Paetzold, Ulrich W., additional, Ho‐Ballie, Anita, additional, Liu, Yun, additional, Macdonald, Daniel, additional, Blakers, Andrew, additional, Wong‐Leung, Jennifer, additional, White, Thomas, additional, Weber, Klaus, additional, and Catchpole, Kylie, additional

Published
2020
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13. Spontaneous enhancement of the stable power conversion efficiency in perovskite solar cells

Author

Moghadamzadeh, Somayeh, primary, Hossain, Ihteaz M., additional, Jakoby, Marius, additional, Abdollahi Nejand, Bahram, additional, Rueda-Delgado, Diana, additional, Schwenzer, Jonas A., additional, Gharibzadeh, Saba, additional, Abzieher, Tobias, additional, Khan, Motiur Rahman, additional, Haghighirad, Amir A., additional, Howard, Ian A., additional, Richards, Bryce S., additional, Lemmer, Uli, additional, and Paetzold, Ulrich W., additional

Published
2020
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14. Chemical vapor deposited polymer layer for efficient passivation of planar perovskite solar cells

Author

Malekshahi Byranvand, Mahdi, primary, Behboodi-Sadabad, Farid, additional, Alrhman Eliwi, Abed, additional, Trouillet, Vanessa, additional, Welle, Alexander, additional, Ternes, Simon, additional, Hossain, Ihteaz Muhaimeen, additional, Khan, Motiur Rahman, additional, Schwenzer, Jonas Alexander, additional, Farooq, Amjad, additional, Richards, Bryce Sydney, additional, Lahann, Joerg, additional, and Paetzold, Ulrich Wilhelm, additional

Published
2020
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15. Injection barrier induced deviations in space charge limited conduction in doped poly(3-methylthiophene) based devices.

Author

Khan, Motiur Rahman, Varade, Vaibhav, Koteswara Rao, K. S. R., and Menon, R.

Subjects
*SPACE-charge-limited conduction, *CARRIER density, *CURRENT-voltage characteristics, *DEVIATION (Statistics), *INJECTION lasers
Abstract

The carrier density dependent current-voltage (J-V) characteristics of electrochemically prepared poly(3-methylthiophene) (P3MeT) have been investigated in Pt/P3MeT/Al devices, as a function of temperature from 280 to 84 K. In these devices, the charge transport is found to be mainly governed by different transport regimes of space charge limited conduction (SCLC). In a lightly doped device, SCLC controlled by exponentially distributed traps (Vl+1 law, l>1) is observed in the intermediate voltage range (0.5-2 V) at all temperatures. However, at higher bias (>2 V), the current deviates from the usual Vl+1 law where the slope is found to be less than 2 of the logJ-logV plot, which is attributed to the presence of the injection barrier. These deviations gradually disappear at higher doping level due to reduction in the injection barrier. Numerical simulations of the Vl+1 law by introducing the injection barrier show good agreement with experimental data. The results show that carrier density can tune the charge transport mechanism in Pt/P3MeT/Al devices to understand the non-Ohmic behavior. The plausible reasons for the origin of injection barrier and the transitions in the transport mechanism with carrier density are discussed. [ABSTRACT FROM AUTHOR]

Published
2015
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16. Dipolar Doping of Organic Semiconductors to Enhance Carrier Injection

Author

Hofmann, Alexander J.L., primary, Züfle, Simon, additional, Shimizu, Kohei, additional, Schmid, Markus, additional, Wessels, Vivien, additional, Jäger, Lars, additional, Altazin, Stéphane, additional, Ikegami, Keitaro, additional, Khan, Motiur Rahman, additional, Neher, Dieter, additional, Ishii, Hisao, additional, Ruhstaller, Beat, additional, and Brütting, Wolfgang, additional

Published
2019
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20. Probing of Barrier Induced Deviations in Current-Voltage Characteristics of Polymer Devices by Impedance Spectroscopy.

Author

Khan, Motiur Rahman, Rao, K. S. R. Koteswara, and Menon, R.

Subjects
*ORGANIC semiconductors, *IMPEDANCE spectroscopy, *ELECTRIC impedance, *CURRENT-voltage characteristics, *POLYMERS
Abstract

Temperature dependent current-voltage measurements have been performed on poly(3-methylthiophene) based devices in metal/polymer/metal geometry in temperature range 90-300 K. Space charge limited current (SCLC) controlled by exponentially distributed traps is observed at all the measured temperatures at intermediate voltage range. At higher voltages, trap-free SCLC is observed at 90 K only while slope less than 2 is observed at higher temperatures which is quiet unusual in polymer devices. Impedance measurements were performed at different bias voltages. The unusual behavior observed in current-voltage characteristics is explained by Cole-Cole plot which gives the signature of interface dipole on electrode/polymer interface. Two relaxation mechanisms are obtained from the real part of impedance vs frequency spectra which confirms the interface related phenomena in the device. [ABSTRACT FROM AUTHOR]

Published
2017
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21. Doping Dependent Charge Transport in Poly(3-methylthiophene) Based Devices.

Author

Khan, Motiur Rahman, Menon, R., and Rao, K. S. R. Koteswara

Subjects
*POLYTHIOPHENES, *DOPING agents (Chemistry), *CURRENT-voltage characteristics, *CHARGE transfer, *TEMPERATURE effect
Abstract

Doping dependent current-voltage measurements have been performed on poly(3-methylthiophene) based devices in metal/polymer/metal geometry in temperature range 90-300 K. In low doped device, space charge limited current (SCLC) controlled by exponentially distributed traps is observed at all the measured temperatures. Trap density and characteristic energy are found to be 2×1015 cm-3 and 29.7 meV respectively. In case of moderately doped device, similar trend is observed with trap density and characteristic energy as 5×1014 cm-3 and 15.5 meV respectively. The high values of trap parameters are attributed to the more disorder in less doped device. A transition from trap-controlled to trap-free SCLC is observed in highly doped device. The plausible reasons for the origin of disorder and the transition in the transport mechanism with doping are discussed. [ABSTRACT FROM AUTHOR]

Published
2016
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