Search for: perovskite
Total 178 records
Article ACS Omega ; Volume 3, Issue 1 , 4 January , 2018 , Pages 46-54 ; 24701343 (ISSN) ; Mohammadi, M. R ; Lianos, P ; Sharif University of Technology
American Chemical Society 2018
A NiOx−graphene oxide (NiOx−GO) hybrid has been prepared by a simple solution-processed method and was used as hole-extraction material in perovskite solar cells with either gold or carbon as back contact electrode. The impact of GO content on the optoelectronic behavior of NiOx and the photovoltaic performance of the fabricated devices has been studied. Thus, GO incorporation showed a significant improvement in the performance of NiOx-based devices. The best attained efficiency was 13.3%, and it was 45% higher than that with pure NiOx. This is attributed to a significant improvement in the hole extraction, recombination resistance, and energy-level matching in comparison to pure NiOx. In...
Improvement of the photovoltaic parameters of perovskite solar cells using a reduced-graphene-oxide-modified titania layer and soluble copper phthalocyanine as a hole transporter, Article Physical Chemistry Chemical Physics ; Volume 20, Issue 4 , 2018 , Pages 2388-2395 ; 14639076 (ISSN) ; Mohammadi, M. R ; Xu, Z. X ; Dracopoulos, V ; Lianos, P ; Sharif University of Technology
Royal Society of Chemistry 2018
Functional perovskite solar cells can be made by using a simple, inexpensive and stable soluble tetra-n-butyl-substituted copper phthalocyanine (CuBuPc) as a hole transporter. In the present study, TiO2/reduced graphene oxide (T/RGO) hybrids were synthesized via an in situ solvothermal process and used as electron acceptor/transport mediators in mesoscopic perovskite solar cells based on soluble CuBuPc as a hole transporter and on graphene oxide (GO) as a buffer layer. The impact of the RGO content on the optoelectronic properties of T/RGO hybrids and on the solar cell performance was studied, suggesting improved electron transport characteristics and photovoltaic parameters. An enhanced...
Reducing surface recombination by a poly(4-vinylpyridine) interlayer in perovskite solar cells with high open-circuit voltage and efficiency, Article ACS Omega ; Volume 3, Issue 5 , 2018 , Pages 5038-5043 ; 24701343 (ISSN) ; Mazloum Ardakani, M ; Gholipour, S ; Tavakoli, M. M ; Taghavinia, N ; Hagfeldt, A ; Tress, W ; Sharif University of Technology
American Chemical Society 2018
Identifying and reducing the dominant recombination processes in perovskite solar cells is one of the major challenges for further device optimization. Here, we show that introducing a thin interlayer of poly(4-vinylpyridine) (PVP) between the perovskite film and the hole transport layer reduces nonradiative recombination. Employing such a PVP interlayer, we reach an open-circuit voltage of 1.20 V for the best devices and a stabilized efficiency of 20.7%. The beneficial effect of the PVP interlayer is proven by statistical analysis of various samples, many of those showing an open-circuit voltage larger than 1.17 V, and a 30 mV increase in average compared to unmodified samples. The reduced...
Coupled ionic-electronic equivalent circuit to describe asymmetric rise and decay of photovoltage profile in perovskite solar cells, Article Scientific Reports ; Volume 9, Issue 1 , 2019 ; 20452322 (ISSN) ; Aryanpour, M ; Mohammadpour, R ; Taghavinia, N ; Sharif University of Technology
Nature Publishing Group 2019
In this research, we employed transient photo-voltage rise and decay measurements to investigate the origin of slow unsymmetrical rise and decay profiles in single and triple cation perovskite solar cells. Drastic changes in photo-voltage decay profile were observed upon insertion of Br−, Cs+ and FA+ ions into perovskite structures. In order to explain our observations, the activation energy for ionic defects was measured and an equivalent circuit model was proposed containing both electrical and ionic components. The electrical branch consists of a diode, the bulk capacitance and resistances for charge transport and recombination. In parallel we introduced an ionic branch describing the...
An easy method to modify PEDOT:PSS/perovskite interfaces for solar cells with efficiency exceeding 15%, Article RSC Advances ; Volume 6, Issue 70 , 2016 , Pages 65594-65599 ; 20462069 (ISSN) ; Tajabadi, F ; Shiu, H. S ; Sedighi, R ; Jokar, E ; Gholipour, S ; Taghavinia, N ; Afshar, S ; Diau, E. W. G ; Sharif University of Technology
Royal Society of Chemistry 2016
Herein, we show that surface treatment of PEDOT:PSS films using propionic acid (PA) results in better device performance for the resulting CH3NH3PbI3 perovskite solar cells (PCE > 15%). N2 blow spreading of PA appears critical in enhanced performance. This weak acid treatment leads to no worse roughness, while providing larger perovskite grains
Modified antisolvent method for improving the performance and stability of triple-cation perovskite solar cells, Article ACS Omega ; Volume 6, Issue 1 , 2021 , Pages 172-179 ; 24701343 (ISSN) ; Golchini, A ; Abdizadeh, K ; Heydari, M ; Forouzandeh, M ; Saki, Z ; Taghavinia, N ; Sharif University of Technology
American Chemical Society 2021
Antisolvent crystallization is known as an effective approach for the deposition of pinhole-free solution-processed perovskite layers for high-performance solar cells. Here, we introduce a modified antisolvent dripping method by adding tetra ethyl orthosilicate (TEOS) into chlorobenzene as a conventional antisolvent. Through TEOS modification, perovskite solar cells show efficiencies as high as 16% with more than 85% retention after 290 h storage at ambient conditions in comparison to 20% in pristine cells. This significant enhancement in efficiency and stability mainly related to the decrement of the density of surface defects, which is confirmed by considerably enhanced photoluminescence...
Article Physical Review B - Condensed Matter and Materials Physics ; Volume 68, Issue 10 , 2003 ; 10980121 (ISSN) ; Akhavan, M ; Sharif University of Technology
Gd(Ba2-xPrx)Cu3O7+δ single phase polycrystalline samples with 0.0 < − x < − 1.0 were investigated for their structural and electronic properties. Due to the solubility limit, the 123 structure forms in the 0.0 < − x < −0.50 range; for x > −0.6, a decomposition of the perovskite-type phases occurs. For x=0.2, there is an orthorhombic-tetragonal phase transition, concurrent with a metal-insulator transition, which is evident in the normal state resistivity. For xc=0.35, the superconductor-insulator transition occurs. An unusual hump has been observed on the resistivity vs temperature curve of the samples for particular values of Pr doping. Based on the Rietveld refinement of the x-ray...
The Effect of Metal Ion Chelation on Formation of Perovskite Versus Perovskite-Related Compounds and The Study of Their Photocatalytic Activity, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
In this study, effect of chelate ligands containing carboxylic, phenolic, and amine functional groups on the synthesis of related-perovskite Ca2Fe2O5 versus perovskite CaFeO3 structures have been investigated. Herein, the application of chelating-agent method, e.g. EDTA, Citric Acid, NTA, malonic acid, maleic acid, catechol, acetylaceton, p-tert-butycatechol, aminophenolic derivative ligand, and 2-hydroxyiminodiacetic acid, in comparison to co-precipitation method was also undertaken. The crystalline structure of the obtained perovskites were compared with those of co-participation method in solid state. Experimentally, it was found that the related XRD bands for CaFeO3 were appeared in the...
Performance Evaluation and Investigation of Nano-Ceramic Membrane in order to Purification of Hydrogen in Laboratory Scale, M.Sc. Thesis Sharif University of Technology ; Sayf Kordi, Ali Akbar ; Zamanian, Akbar ; Ganji Babakhani, Ensieh
Purification of hydrogen, as a clean source of energy has attracted great deal of attention in recent years. Among all available H2 separation methods, membrane technology has been known as the most appropriate way to produce hydrogen with high purity. In this study, we have tried to synthesis and evaluate the performance of perovskite ceramic membranes. The aim of preparing this type of membranes is to use them in separation processes in order to achieve H2 with high purity of >99%. First, general concepts about membranes are discussed. Then synthesis, recognition and performance evaluation of some perovskite membranes are presented. To prepare membranes, ceramic powders are synthesized by...
Synthesis, characterization, and application of a new tripodal ligand for the preparation of LSCF(6482) perovskite, Article Chemical Papers ; Vol. 68, issue. 7 , 2014 , p. 989-994 ; Ghanbari, B ; Hajibabaei, H ; Sharif University of Technology
The main aim of this paper was to study the effect of a new tripodal chelating agent on La1-x Sr x Co1-y Fe y O3-δ perovskite prepared by the complexation method. For this purpose, a phenolic derivative of glycine (L) was synthesized applying the Mannich reaction and characterized by NMR and IR spectroscopies as well as by elemental analysis. To evaluate the complexation capability of L, its formation constants with the perovskite cations were measured. Comparison of these results with those reported for the complexaion with glycine, introduced L as a good candidate for the complexation with Fe(III) and La(III) cations. Furthermore, the powder XRD observations confirmed an improvement in the...
Enhancing the formation of tetragonal phase in perovskite nanocrystals using an ultrasound assisted wet chemical method, Article Ultrasonics Sonochemistry ; Volume 33 , 2016 , Pages 141-149 ; 13504177 (ISSN) ; Ashiri, R ; Sharif University of Technology
Synthesis of highly-pure tetragonal perovskite nanocrystals is the key challenge facing the development of new electronic devices. Our results have indicated that ultrasonication is able in enhancing the formation of tetragonal phase in perovskite nanocrystals. In the current research, multicationic oxide perovskite (ATiO3; A: Ba, Sr, Ba0.6Sr0.4) nanopowders are synthesized successfully by a general methodology without a calcination step. The method is able to synthesize high-purity nanoscale ATiO3 (BaTiO3, SrTiO3, Ba0.6Sr0.4TiO3) with tetragonal symmetry at a lower temperature and in a shorter time span in contrast to the literature. To reach an in-depth understanding of the scientific...
Article Advanced Energy Materials ; Volume 6, Issue 20 , 2016 ; 16146832 (ISSN) ; Correa Baena, J. P ; Domanski, K ; Matsui, T ; Steier, L ; Giordano, F ; Tajabadi, F ; Tress, W ; Saliba, M ; Abate, A ; Morteza Ali, A ; Taghavinia, N ; Grätzel, M ; Hagfeldt, A ; Sharif University of Technology
Wiley-VCH Verlag 2016
A low-cost carbon cloth is applied in perovskite solar cells (PSC) as a collector composite and degradation inhibitor. This study incorporates carbon fibers as a back contact in perovskite solar cells, which results in enhancement in all photovoltaic parameters. This material is suitable for large-scale fabrication of PSCs as it has shown an improved long-term stability when compared to the gold counterpart under elevated temperatures
Two-Step Physical Deposition of a Compact CuI Hole-Transport Layer and the Formation of an Interfacial Species in Perovskite Solar Cells, Article ChemSusChem ; 2016 , Pages 1929-1937 ; 18645631 (ISSN) ; Nejand, B. A ; Moshaii, A ; Mohammadian, N ; Alizadeh, A. H ; Mohammadpour, R ; Ahmadi, V ; Alizadeh, A ; Sharif University of Technology
Wiley-VCH Verlag 2016
A simple and practical approach is introduced for the deposition of CuI as an inexpensive inorganic hole-transport material (HTM) for the fabrication of low cost perovskite solar cells (PSCs) by gas–solid phase transformation of Cu to CuI. The method provides a uniform and well-controlled CuI layer with large grains and good compactness that prevents the direct connection between the contact electrodes. Solar cells prepared with CuI as the HTM with Au electrodes displays an exceptionally high short-circuit current density of 32 mA cm−2, owing to an interfacial species formed between the perovskite and the Cu resulting in a long wavelength contribution to the incident photon-to-electron...
A three-step method for the deposition of large cuboids of organic–inorganic perovskite and application in solar cells, Article ChemPhysChem ; 2016 , Pages 2389-2394 ; 14394235 (ISSN) ; Malekshahi Byranvand, M ; Tajabadi, F ; Afshar, Sh ; Taghavinia, N ; Sharif University of Technology
A three-step method for the deposition of CH3NH3PbI3 perovskite films with a high crystalline structure and large cuboid overlayer morphology is reported. The method includes PbI2 deposition, which is followed by dipping into a solution of C4H9NH3I (BAI) and (BA)2PbI4 perovskite formation. In the final step, the poorly thermodynamically stable (BA)2PbI4 phase converts into the more stable CH3NH3PbI3 perovskite by dipping into a solution of CH3NH3I. The final product is characterized by XRD, SEM, UV/Vis, and photoluminescence analysis methods. The experimental results indicate that the prepared perovskite has cuboids with high crystallinity and large sizes (up to 1 μm), as confirmed by XRD...
Photovoltaic performance improvement in vacuum-assisted meniscus printed triple-cation mixed-halide perovskite films by surfactant engineering, Article ACS Applied Energy Materials ; Volume 2, Issue 9 , 2019 , Pages 6209-6217 ; 25740962 (ISSN) ; Abdollah Zadeh, A ; Dehghani, M ; Taghavinia, N ; Sharif University of Technology
American Chemical Society 2019
Scalable coating methods have recently emerged as practical alternative deposition techniques to the conventional spin-coating despite their lower yielding power conversion efficiencies (PCEs). The most important barrier acting against the use of scalable deposition methods to get a highly absorbing (>95%) film with controlled morphology in the high crystallinity of perovskite particles is the impossibility of antisolvent dripping during the deposition. Here, we demonstrate the positive role of both the surfactant-engineering and the vacuum-annealing (<100 Pa) process in improving the device performance to overcome this limit. A detailed optimization of the vacuum-assisted meniscus printing...
Article Solar Energy Materials and Solar Cells ; Volume 191 , 2019 , Pages 148-156 ; 09270248 (ISSN) ; Abdollah zadeh, A ; Akbari, H. R ; Taghavinia, N ; Sharif University of Technology
Elsevier B.V 2019
Scale-up deposition methods in perovskite solar cell research, are mostly used under humidity environment outside the glove-box. Also, the as-printed absorbing layer before the post-annealing process is always wet. Thus, controlling the morphology and crystallization of perovskite thin-films in up-scaled deposition systems is difficult and strongly investigated by the researchers. In this work, we introduce an anti-solvent-free meniscus printing method in which, the absorbing perovskite film with optimal performance is achieved. To this end, we check the printing parameters to get to the optimized film characteristics. Also, a vacuum chamber (<100 Pa) is used for 30 s to remove the solvent...
Atomic layer deposition of electron selective snox and ZnO films on mixed halide perovskite: compatibility and performance, Article ACS Applied Materials and Interfaces ; Volume 9, Issue 35 , 2017 , Pages 29707-29716 ; 19448244 (ISSN) ; Aitola, K ; Sveinbjörnsson, K ; Saki, Z ; Larsson, F ; Törndahl, T ; Johansson, E ; Boschloo, G ; Edoff, M ; Sharif University of Technology
The compatibility of atomic layer deposition directly onto the mixed halide perovskite formamidinium lead iodide:methylammonium lead bromide (CH(NH2)2, CH3NH3)Pb(I,Br)3 (FAPbI3:MAPbBr3) perovskite films is investigated by exposing the perovskite films to the full or partial atomic layer deposition processes for the electron selective layer candidates ZnO and SnOx. Exposing the samples to the heat, the vacuum, and even the counter reactant of H2O of the atomic layer deposition processes does not appear to alter the perovskite films in terms of crystallinity, but the choice of metal precursor is found to be critical. The Zn precursor Zn(C2H5)2 either by itself or in combination with H2O during...
Effect of CsCl additive on the morphological and optoelectronic properties of formamidinium lead iodide perovskite, Article Solar RRL ; Volume 3, Issue 11 , 2019 ; 2367198X (ISSN) ; Prochowicz, D ; Yadav, P ; Tavakoli, M. M ; Nimbalkar, A ; Bhoite, S. P ; Hong, C. K ; Sharif University of Technology
Wiley-VCH Verlag 2019
The quality of perovskite films plays a crucial role in improving the optoelectronic properties and performance of perovskite solar cells (PSCs). Herein, high-quality CsxFA1−xPbI3 perovskite films with different compositions (x = 0, 5, 10, and 15) are achieved by controlling the amount of cesium chloride (CsCl) in the respective FAPbI3 precursor solution. The effects of CsCl addition on the morphological and optoelectronic properties of the resulting perovskite films and on the performance of the corresponding devices are systematically studied. Introduction of CsCl into FAPbI3 shows a great potential to stabilize the α-FAPbI3 perovskite phase by forming CsxFA1−xPbI3 films with improved...
M.Sc. Thesis Sharif University of Technology ; Simchi, Abdol Reza
In the last years, perovskite QDs have emerged as the novel candidate due to their unique optical properties such as high-absorption coefficient, long-range charge transport, low exciton-binding energy, and etc. Nonetheless, poor stability of perovskite in ambient conditions made researchers to consider this issue. Recently, amoung various types of organic-inorganic perovskites, Formamidinium lead iodide has attracted tremendous attention due to its near IR absorption wavelength in addition to the higher stability compared to MAPbI3. In this work, FAPbI3 perovskite stability improvement was investigated by several methods under different conditions. In the first step, FAPbI3 QDs colloidal...
M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza ; Seyyed Reyhani, Morteza
Last generation of solar cells which are organo-metal halide perovskite solar cells (PSCs) with power conversion efficiency over 20% are increasingly comparable to the silicon types, these PSCs are poorly stable under working environment. Carbon-based PSCs with lower cost and more stability seem a better choice for commercialization in future. In these PSCs TiO2 and NiO are working as electron and hole transporting materials, respectively. In addition, ZrO2 film between two mentioned layers works as a buffer layer to prevent direct contact. In this thesis, the initial powder, necessary for fabricating the buffer layer is synthesized at the first place. Then, since the printing method is a...