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Michael Gratzel - One of the best experts on this subject based on the ideXlab platform.
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Hole-Transport Materials for Perovskite Solar Cells
Angewandte Chemie - International Edition, 2016Co-Authors: Laura Calio, Samrana Kazim, Michael Gratzel, Shahzada AhmadAbstract:The pressure to move towards renewable energy has inspired researchers to look for ideas in photovoltaics that may lead to a major breakthrough. Recently the use of perovskites as a Light Harvester has lead to stunning progress. The power conversion efficiency of perovskite solar cells is now approaching parity (>22 %) with that of the established technology which took decades to reach this level of performance. The use of a hole transport material (HTM) remains indispensable in perovskite solar cells. Perovskites can conduct holes, but they are present at low levels, and for efficient charge extraction a HTM layer is a prerequisite. Herein we provide an overview of the diverse types of HTM available, from organic to inorganic, in the hope of encouraging further research and the optimization of these materials.
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perovskite as Light Harvester a game changer in photovoltaics
Angewandte Chemie, 2014Co-Authors: Samrana Kazim, Mohammad Khaja Nazeeruddin, Michael Gratzel, Shahzada AhmadAbstract:It is not often that the scientific community is blessed with a material, which brings enormous hopes and receives special attention. When it does, it expands at a rapid pace and its every dimension creates curiosity. One such material is perovskite, which has triggered the development of new device architectures in energy conversion. Perovskites are of great interest in photovoltaic devices due to their panchromatic Light absorption and ambipolar behavior. Power conversion efficiencies have been doubled in less than a year and over 15% is being now measured in labs. Every digit increment in efficiency is being celebrated widely in the scientific community and is being discussed in industry. Here we provide a summary on the use of perovskite for inexpensive solar cells fabrication. It will not be unrealistic to speculate that one day perovskite-based solar cells can match the capability and capacity of existing technologies.
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yttrium substituted nanocrystalline tio2 photoanodes for perovskite based heterojunction solar cells
Nanoscale, 2014Co-Authors: Anna L Domanski, Aravind Kumar Chandiran, Mohammad Khaja Nazeeruddin, Shahzada Ahmad, Rudiger Berger, Hansjurgen Butt, Thomas Moehl, Nicolas Tetreault, Michael GratzelAbstract:We report the use of Y3+-substituted TiO2 (0.5%Y–TiO2) in solid-state mesoscopic solar cells, consisting of CH3NH3PbI3 as the Light Harvester and spiro-OMeTAD as the hole transport material. A power conversion efficiency of 11.2% under simulated AM 1.5 full sun illumination was measured. A 15% improvement in the short-circuit current density was obtained compared with pure TiO2, due to the effect of Y3+ on the dimensions of perovskite nanoparticles formed on the semiconductor surface, showing that the surface modification of the semiconductor is an effective way to improve the Light Harvesters' morphology and electron transfer properties in the solid-state mesoscopic solar cells.
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mesoscopic ch3nh3pbi3 tio2 heterojunction solar cells
Journal of the American Chemical Society, 2012Co-Authors: Lioz Etgar, Zhaosheng Xue, Aravind Kumar Chandiran, Bin Liu, Qin Peng, Mohammad Khaja Nazeeruddin, Peng Gao, Michael GratzelAbstract:We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite/TiO2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH3NH3I and PbI2 in γ-butyrolactone on a 400 nm thick film of TiO2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH3NH3PbI3 as a back contact. Importantly, the CH3NH3PbI3 nanoparticles assume here simultaneously the roles of both Light Harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent Jsc= 16.1 mA/cm2, open-circuit photovoltage Voc = 0.631 V, and a fill factor FF = 0.57, corresponding to a Light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar Light of 1000 W/m2 intensity. At a lower Light intensity of 100W/m2, a PCE of 7.3% was m...
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Mesoscopic CH3NH3PbI3/TiO2 Heterojunction Solar Cells
Journal of the American Chemical Society, 2012Co-Authors: Lioz Etgar, Zhaosheng Xue, Aravind Kumar Chandiran, Bin Liu, Qin Peng, Mohammad Khaja Nazeeruddin, Peng Gao, Michael GratzelAbstract:We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite/TiO2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH3NH3I and PbI2 in gamma-butyrolactone on a 400 nm thick film of TiO2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH3NH3PbI3 as a back contact. Importantly, the CH3NH3PbI3 nanoparticles assume here simultaneously the roles of both Light Harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent Jsc= 16.1 mA/cm2, open-circuit photovoltage Voc = 0.631 V, and a fill factor FF = 0.57, corresponding to a Light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar Light of 1000 W/m2 intensity. At a lower Light intensity of 100W/m2, a PCE of 7.3% was measured. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost, high-efficiency solar cells.
Lioz Etgar - One of the best experts on this subject based on the ideXlab platform.
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Hole Conductor Free Perovskite-based Solar Cells
2016Co-Authors: Lioz EtgarAbstract:The current research concentrates on the investigation of perovskite based solar cells, when the Perovskite hybrids function in a unique way as the Light Harvester and hole conductor simultaneously.
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Hole Transport Material (HTM) Free Perovskite Solar Cell
Hole Conductor Free Perovskite-based Solar Cells, 2016Co-Authors: Lioz EtgarAbstract:At the same time of the perovskite discovery to function as efficient Light Harvester in the solar cell, Etgar et al. [1] first proposed a heterojunction device structure of FTO/TiO2/CH3NH3PbI3/Au in which CH3NH3PbI3 was used as a p-type semiconductor and 500 nm mesoscopic TiO2 was used as an n-type semiconductor.
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Hole-transport material-free perovskite-based solar cells
Mrs Bulletin, 2015Co-Authors: Lioz EtgarAbstract:Recent discoveries have revealed a breakthrough in the photovoltaics (PVs) field using organometallic perovskites as Light Harvesters in the solar cell. The organometal perovskite arrangement is self-assembled as alternate layers via a simple low-cost procedure. These organometal perovskites promise several benefits not provided by the separate constituents. This overview concentrates on implementing perovskites in PV cells such that the perovskite layers are used as the Light Harvester as well as the hole-conducting component. Eliminating hole-transport material (HTM) in this solar-cell structure avoids oxidation, reduces costs, and provides better stability and consistent results. Aspects of HTM-free perovskite solar cells discussed in this article include (1) depletion regions, (2) high voltages, (3) panchromatic responses, (4) chemical modifications, and (5) contacts in HTM-free perovskite solar cells. Elimination of HTM could expand possibilities to explore new interfaces in these solar cells, while over the long term, these uniquely structured HTM-free solar cells could offer valuable benefits for future PV and optoelectronics applications.
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The electronic structure of metal oxide/organo metal halide perovskite junctions in perovskite based solar cells
Scientific Reports, 2015Co-Authors: Alex Dymshits, Alex Henning, Gideon Segev, Y Rosenwaks, Lioz EtgarAbstract:Cross-sections of a hole-conductor-free CH_3NH_3PbI_3 perovskite solar cell were characterized with Kelvin probe force microscopy. A depletion region width of about 45 nm was determined from the measured potential profiles at the interface between CH_3NH_3PbI_3 and nanocrystalline TiO_2, whereas a negligible depletion was measured at the CH_3NH_3PbI_3/Al_2O_3 interface. A complete solar cell can be realized with the CH_3NH_3PbI_3 that functions both as Light Harvester and hole conductor in combination with a metal oxide. The band diagrams were estimated from the measured potential profile at the interfaces and are critical findings for a better understanding and further improvement of perovskite based solar cells.
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Depletion region effect of highly efficient hole conductor free CH3NH3PbI3 perovskite solar cells
Phys Chem Chem Phys, 2014Co-Authors: Sigalit Aharon, Shany Gamliel, B Cohen, Lioz EtgarAbstract:The inorganic-organic perovskite is currently attracting a lot of attention due to its use as a Light Harvester in solar cells. The large absorption coefficients, high carrier mobility and good stability of organo-lead halide perovskites present good potential for their use as Light Harvesters in mesoscopic heterojunction solar cells. This work concentrated on a unique property of the lead halide perovskite, its function simultaneously as a Light Harvester and a hole conductor in the solar cell. A two-step deposition technique was used to optimize the perovskite deposition and to enhance the solar cell efficiency. It was revealed that the photovoltaic performance of the hole conductor free perovskite solar cell is strongly dependent on the depletion layer width which was created at the TiO2-CH3NH3PbI3 junction. X-ray diffraction measurements indicate that there were no changes in the crystallographic structure of the CH3NH3PbI3 perovskite over time, which supports the high stability of these hole conductor free perovskite solar cells. Furthermore, the power conversion efficiency of the best cells reached 10.85% with a fill factor of 68%, a Voc of 0.84 V, and a Jsc of 19 mA cm(-2), the highest efficiency to date of a hole conductor free perovskite solar cell.
Wenyi Wu - One of the best experts on this subject based on the ideXlab platform.
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spray reaction prepared fa1 xcsxpbi3 solid solution as a Light Harvester for perovskite solar cells with improved humidity stability
RSC Advances, 2016Co-Authors: Wenyi Wu, Hongcui Li, Bo Zheng, Jing Xu, Dawei ZhangAbstract:FA1−xCsxPbI3 solid solution films are prepared as Light Harvesters for perovskite solar cells by a spray reaction. Cs+ ions can improve the quality of the Light Harvester film, and the average PCE of devices increases from 11.3% for FAPbI3 to 14.2% for FA0.9Cs0.1PbI3. Moreover, FA0.9Cs0.1PbI3-based devices exhibit remarkable improvement on humidity stability.
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Spray reaction prepared FA1−xCsxPbI3 solid solution as a Light Harvester for perovskite solar cells with improved humidity stability
RSC Advances, 2016Co-Authors: Wenyi Wu, Hongcui Li, Bo Zheng, Jing Xu, Dawei ZhangAbstract:FA1−xCsxPbI3 solid solution films are prepared as Light Harvesters for perovskite solar cells by a spray reaction. Cs+ ions can improve the quality of the Light Harvester film, and the average PCE of devices increases from 11.3% for FAPbI3 to 14.2% for FA0.9Cs0.1PbI3. Moreover, FA0.9Cs0.1PbI3-based devices exhibit remarkable improvement on humidity stability.
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efficient Light Harvester layer prepared by solid mist interface reaction for perovskite solar cells
ACS Applied Materials & Interfaces, 2015Co-Authors: Hongcui Li, Wenyi Wu, Yanhua LiAbstract:A solid/mist reaction method is developed to produce well-crystallized Light Harvester layers without pinhole defects for perovskite solar cells. The reaction based on mist precursor can be facilely operated with low process temperature. And it can effectively control the volume of CH3NH3I solution and the reaction temperature, which affect the quality of perovskite Harvester layers and the performance of perovskite solar cells remarkably. Under optimized condition, the efficiencies of devices reach 16.2% with the average efficiency of 14.9%. The solid/mist reaction is also used to fabricate planar junction solar cells and a PCE of 14.9% is obtained.
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Efficient Light Harvester Layer Prepared by Solid/Mist Interface Reaction for Perovskite Solar Cells.
ACS Applied Materials & Interfaces, 2015Co-Authors: Hongcui Li, Wenyi Wu, Yanhua LiAbstract:A solid/mist reaction method is developed to produce well-crystallized Light Harvester layers without pinhole defects for perovskite solar cells. The reaction based on mist precursor can be facilely operated with low process temperature. And it can effectively control the volume of CH3NH3I solution and the reaction temperature, which affect the quality of perovskite Harvester layers and the performance of perovskite solar cells remarkably. Under optimized condition, the efficiencies of devices reach 16.2% with the average efficiency of 14.9%. The solid/mist reaction is also used to fabricate planar junction solar cells and a PCE of 14.9% is obtained.
Hongcui Li - One of the best experts on this subject based on the ideXlab platform.
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spray reaction prepared fa1 xcsxpbi3 solid solution as a Light Harvester for perovskite solar cells with improved humidity stability
RSC Advances, 2016Co-Authors: Wenyi Wu, Hongcui Li, Bo Zheng, Jing Xu, Dawei ZhangAbstract:FA1−xCsxPbI3 solid solution films are prepared as Light Harvesters for perovskite solar cells by a spray reaction. Cs+ ions can improve the quality of the Light Harvester film, and the average PCE of devices increases from 11.3% for FAPbI3 to 14.2% for FA0.9Cs0.1PbI3. Moreover, FA0.9Cs0.1PbI3-based devices exhibit remarkable improvement on humidity stability.
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Spray reaction prepared FA1−xCsxPbI3 solid solution as a Light Harvester for perovskite solar cells with improved humidity stability
RSC Advances, 2016Co-Authors: Wenyi Wu, Hongcui Li, Bo Zheng, Jing Xu, Dawei ZhangAbstract:FA1−xCsxPbI3 solid solution films are prepared as Light Harvesters for perovskite solar cells by a spray reaction. Cs+ ions can improve the quality of the Light Harvester film, and the average PCE of devices increases from 11.3% for FAPbI3 to 14.2% for FA0.9Cs0.1PbI3. Moreover, FA0.9Cs0.1PbI3-based devices exhibit remarkable improvement on humidity stability.
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efficient Light Harvester layer prepared by solid mist interface reaction for perovskite solar cells
ACS Applied Materials & Interfaces, 2015Co-Authors: Hongcui Li, Wenyi Wu, Yanhua LiAbstract:A solid/mist reaction method is developed to produce well-crystallized Light Harvester layers without pinhole defects for perovskite solar cells. The reaction based on mist precursor can be facilely operated with low process temperature. And it can effectively control the volume of CH3NH3I solution and the reaction temperature, which affect the quality of perovskite Harvester layers and the performance of perovskite solar cells remarkably. Under optimized condition, the efficiencies of devices reach 16.2% with the average efficiency of 14.9%. The solid/mist reaction is also used to fabricate planar junction solar cells and a PCE of 14.9% is obtained.
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Efficient Light Harvester Layer Prepared by Solid/Mist Interface Reaction for Perovskite Solar Cells.
ACS Applied Materials & Interfaces, 2015Co-Authors: Hongcui Li, Wenyi Wu, Yanhua LiAbstract:A solid/mist reaction method is developed to produce well-crystallized Light Harvester layers without pinhole defects for perovskite solar cells. The reaction based on mist precursor can be facilely operated with low process temperature. And it can effectively control the volume of CH3NH3I solution and the reaction temperature, which affect the quality of perovskite Harvester layers and the performance of perovskite solar cells remarkably. Under optimized condition, the efficiencies of devices reach 16.2% with the average efficiency of 14.9%. The solid/mist reaction is also used to fabricate planar junction solar cells and a PCE of 14.9% is obtained.
Mohammad Khaja Nazeeruddin - One of the best experts on this subject based on the ideXlab platform.
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enhanced electronic properties in mesoporous tio2 via lithium doping for high efficiency perovskite solar cells
Nature Communications, 2016Co-Authors: Fabrizio Giordano, Mohammad Khaja Nazeeruddin, Sang Hyuk Im, Shaik M Zakeeruddin, Antonio Abate, Juan Pablo Correa Baena, Michael Saliba, Taisuke Matsui, Anders Hagfeldt, Michael GraetzelAbstract:Perovskite solar cells are one of the most promising photovoltaic technologies with their extraordinary progress in efficiency and the simple processes required to produce them. However, the frequent presence of a pronounced hysteresis in the current voltage characteristic of these devices arises concerns on the intrinsic stability of organo-metal halides, challenging the reliability of technology itself. Here, we show that n-doping of mesoporous TiO2 is accomplished by facile post treatment of the films with lithium salts. We demonstrate that the Li-doped TiO2 electrodes exhibit superior electronic properties, by reducing electronic trap states enabling faster electron transport. Perovskite solar cells prepared using the Li-doped films as scaffold to host the CH3NH3PbI3 Light Harvester produce substantially higher performances compared with undoped electrodes, improving the power conversion efficiency from 17 to over 19% with negligible hysteretic behaviour (lower than 0.3%).
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perovskite as Light Harvester a game changer in photovoltaics
Angewandte Chemie, 2014Co-Authors: Samrana Kazim, Mohammad Khaja Nazeeruddin, Michael Gratzel, Shahzada AhmadAbstract:It is not often that the scientific community is blessed with a material, which brings enormous hopes and receives special attention. When it does, it expands at a rapid pace and its every dimension creates curiosity. One such material is perovskite, which has triggered the development of new device architectures in energy conversion. Perovskites are of great interest in photovoltaic devices due to their panchromatic Light absorption and ambipolar behavior. Power conversion efficiencies have been doubled in less than a year and over 15% is being now measured in labs. Every digit increment in efficiency is being celebrated widely in the scientific community and is being discussed in industry. Here we provide a summary on the use of perovskite for inexpensive solar cells fabrication. It will not be unrealistic to speculate that one day perovskite-based solar cells can match the capability and capacity of existing technologies.
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yttrium substituted nanocrystalline tio2 photoanodes for perovskite based heterojunction solar cells
Nanoscale, 2014Co-Authors: Anna L Domanski, Aravind Kumar Chandiran, Mohammad Khaja Nazeeruddin, Shahzada Ahmad, Rudiger Berger, Hansjurgen Butt, Thomas Moehl, Nicolas Tetreault, Michael GratzelAbstract:We report the use of Y3+-substituted TiO2 (0.5%Y–TiO2) in solid-state mesoscopic solar cells, consisting of CH3NH3PbI3 as the Light Harvester and spiro-OMeTAD as the hole transport material. A power conversion efficiency of 11.2% under simulated AM 1.5 full sun illumination was measured. A 15% improvement in the short-circuit current density was obtained compared with pure TiO2, due to the effect of Y3+ on the dimensions of perovskite nanoparticles formed on the semiconductor surface, showing that the surface modification of the semiconductor is an effective way to improve the Light Harvesters' morphology and electron transfer properties in the solid-state mesoscopic solar cells.
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efficient inorganic organic hybrid heterojunction solar cells containing perovskite compound and polymeric hole conductors
Nature Photonics, 2013Co-Authors: Jin Hyuck Heo, Tarak N. Mandal, Jun Hong Noh, Sang Hyuk Im, Choongsun Lim, Jeong Ah Chang, Yong Hui Lee, Hijung Kim, Arpita Sarkar, Mohammad Khaja NazeeruddinAbstract:Inorganic‐organic hybrid structures have become innovative alternatives for next-generation dye-sensitized solar cells, because they combine the advantages of both systems. Here, we introduce a layered sandwich-type architecture, the core of which comprises a bicontinuous three-dimensional nanocomposite of mesoporous (mp)-TiO2 ,w ith CH 3NH3PbI3 perovskite as Light Harvester, as well as a polymeric hole conductor. This platform creates new opportunities for the development of low-cost, solution-processed, high-efficiency solar cells. The use of a polymeric hole conductor, especially poly-triarylamine, substantially improves the open-circuit voltage V oc and fill factor of the cells. Solar cells based on these inorganic‐organic hybrids exhibit a short-circuit current density Jsc of 16.5 mA cm 22 , Voc of 0.997 V and fill factor of 0.727, yielding a power conversion efficiency of 12.0% under standard AM 1.5 conditions.
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mesoscopic ch3nh3pbi3 tio2 heterojunction solar cells
Journal of the American Chemical Society, 2012Co-Authors: Lioz Etgar, Zhaosheng Xue, Aravind Kumar Chandiran, Bin Liu, Qin Peng, Mohammad Khaja Nazeeruddin, Peng Gao, Michael GratzelAbstract:We report for the first time on a hole conductor-free mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite/TiO2 heterojunction solar cell, produced by deposition of perovskite nanoparticles from a solution of CH3NH3I and PbI2 in γ-butyrolactone on a 400 nm thick film of TiO2 (anatase) nanosheets exposing (001) facets. A gold film was evaporated on top of the CH3NH3PbI3 as a back contact. Importantly, the CH3NH3PbI3 nanoparticles assume here simultaneously the roles of both Light Harvester and hole conductor, rendering superfluous the use of an additional hole transporting material. The simple mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cell shows impressive photovoltaic performance, with short-circuit photocurrent Jsc= 16.1 mA/cm2, open-circuit photovoltage Voc = 0.631 V, and a fill factor FF = 0.57, corresponding to a Light to electric power conversion efficiency (PCE) of 5.5% under standard AM 1.5 solar Light of 1000 W/m2 intensity. At a lower Light intensity of 100W/m2, a PCE of 7.3% was m...