Listar por autoría "944af19c-873b-499a-bde5-e98c03ab08dc"

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    • openAccess   A Photoelectrochemical study of Bismuth Vanadate Photoanodes for Solar Water Splitting 

      Ravishankar, Sandheep Universitat Jaume I (2016-07-04)
      Bismuth Vanadate (BiVO4) is a promising photoanode in the field of solar water splitting due to its low cost of synthesis, low toxicity, good stability and high theoretical photocurrent density. However, several reports ...

    • openAccess   Combining Modulated Techniques for the Analysis of Photosensitive Devices 

      Alvarez, Agustin; Ravishankar, Sandheep; Fabregat-Santiago, Francisco Wiley-VCH GmbH (2021-09-03)
      Small-perturbation techniques such as impedance spectroscopy (IS), inten-sity-modulated photocurrent spectroscopy (IMPS), and intensity-modulated photovoltage spectroscopy (IMVS) are useful tools to characterize and model ...

    • openAccess   Device Physics of Hybrid Perovskite Solar cells: Theory and Experiment 

      Lopez-Varo, Pilar; Jiménez Tejada, Juan Antonio; Garcia-Rosell, Manuel; Ravishankar, Sandheep; Garcia-Belmonte, Germà; Bisquert, Juan; Almora Rodríguez, Osbel Wiley (2018)
      Perovskite solar cells (PSCs) exhibit a series of distinctive features in their optoelectronic response which have a crucial influence on the performance, particularly for long-time response. Here, a survey of recent ...

    • openAccess   Effects of Frequency Dependence of the External Quantum Efficiency of Perovskite Solar Cells 

      Ravishankar, Sandheep; Aranda Alonso, Clara; Boix, Pablo P; Anta, Juan A.; Bisquert, Juan; Garcia-Belmonte, Germà American Chemical Society (2018-05)
      Perovskite solar cells are known to show very long response time scales, on the order of milliseconds to seconds. This generates considerable doubt over the validity of the measured external quantum efficiency (EQE) and ...

    • closedAccess   Effects of Ion Distributions on Charge Collection in Perovskite Solar Cells 

      Lopez-Varo, Pilar; Jiménez Tejada, Juan Antonio; García-Rosell, Manuel; Anta, Juan A.; Ravishankar, Sandheep; Bou, Agustín; Bisquert, Juan American Chemical Society (2017)

    • openAccess   Influence of Charge Transport Layers on Open-Circuit Voltage and Hysteresis in Perovskite Solar Cells 

      Ravishankar, Sandheep; Gharibzadeh, Saba; Roldán-Carmona, Cristina; Grancini, Giulia; Lee, Yonghui; Ralaiarisoa, Maryline; Asiri, Abdullah M.; Koch, Nobert; Bisquert, Juan; Nazeeruddin, Mohammad Khaja Elsevier (2018-04)
      Perovskite materials have experienced an impressive improvement in photovoltaic performance due to their unique combination of optoelectronic properties. Their remarkable progression, facilitated by the use of different ...

    • openAccess   Intensity-Modulated Photocurrent Spectroscopy and Its Application to Perovskite Solar Cells 

      Ravishankar, Sandheep; Riquelme, Antonio; Sarkar, Shaibal; García-Batlle, Marisé; Garcia-Belmonte, Germà; Bisquert, Juan American Chemical Society (2020-09-23)
      Frequency domain techniques are useful tools to characterize processes occurring on different time scales in solar cells and solar fuel devices. Intensity-modulated photocurrent spectroscopy (IMPS) is one such technique ...

    • openAccess   Intensity-Modulated Photocurrent Spectroscopy for Solar Energy Conversion Devices: What Does a Negative Value Mean? 

      Cardenas-Morcoso, Drialys; Bou, Agustín; Ravishankar, Sandheep; García-Tecedor, Miguel; Gimenez, Sixto; Bisquert, Juan American Chemical Society (2020-01-10)
      Small perturbation techniques constitute a wide family of tools for the characterization of solar energy conversion devices such as photovoltaic cells and photoelectrochemical (PEC) cells for solar fuel production. Two ...

    • openAccess   Interpretation of Mott-Schottky plots of photoanodes for water splitting 

      Ravishankar, Sandheep; Bisquert, Juan; Kirchartz, Thomas The Royal Society of Chemistry (2022-03-31)
      A large body of literature reports that both bismuth vanadate and haematite photoanodes are semiconductors with an extremely high doping density between 1018 and 1021 cm−3. Such values are obtained from Mott–Schottky plots ...

    • openAccess   Near-complete suppression of surface losses and total internal quantum efficiency in BiVO4 photoanodes 

      Trzesniewski, Bartek J.; Digdaya, Ibadillah; Nagaki, Tetsuro; Ravishankar, Sandheep; Herraiz Cardona, Isaac; Vermaas, David; Longo, Alessandro; Gimenez, Sixto; Smith, Wilson A. Royal Society of Chemistry (2017-05-26)
      Bismuth vanadate (BiVO4) is one of the most efficient light absorbing metal oxides for solar water splitting. BiVO4 photoanodes immersed in an electrolyte in an open circuit configuration and exposed to simulated solar ...

    • closedAccess   Overcoming Charge Collection Limitation at Solid/Liquid Interface by a Controllable Crystal Deficient Overlayer 

      Zhang, Kan; Ravishankar, Sandheep; Ma, Ming; Veerappan, Ganapathy; Bisquert, Juan; Fabregat-Santiago, Francisco; Park, Jong Hyeok Wiley (2017)
      Bulk and surface charge recombination of photoelectrode are two key processes that significantly hinder solar-to-fuel conversion of photoelectrochemical cell (PEC). In this study, the function of a “crystal-deficient” ...

    • closedAccess   Perovskite Solar Cell Modeling Using Light- and Voltage-Modulated Techniques 

      Ravishankar, Sandheep; Aranda Alonso, Clara; Sanchez, Sandy; Bisquert, Juan; Saliba, Michael; Garcia-Belmonte, Germà American Chemical Society (2019-02-27)
      The analysis of the impedance spectroscopy (IS) data of perovskite solar cells (PSCs) has been challenging so far, with the low-frequency phenomena in particular yielding ambivalent results and interpretations. We tackle ...

    • openAccess   Removing Instability-Caused Low-Frequency Features in Small Perturbation Spectra of Perovskite Solar Cells 

      Ravishankar, Sandheep; García-Batlle, Marisé; Bisquert, Juan; Garcia-Belmonte, Germà; Odrobina, Jann; Schiller, Carl-Albrecht American Chemical Society (2020-06-29)
      Small-perturbation frequency-domain techniques such as impedance spectroscopy and intensity-modulated photocurrent spectroscopy (IMPS) have become important methods for the investigation of the physical working mechanisms ...

    • openAccess   Stability of dye-sensitized solar cells under extended thermal stress 

      Yadav, Surendra K.; Ravishankar, Sandheep; Pescetelli, Sara; Agresti, Antonio; Fabregat-Santiago, Francisco; Di Carlo, Aldo Royal Society of Chemistry (2017)
      In the last few decades, dye-sensitized solar cell (DSC) technology has been demonstrated to be a promising candidate for low cost energy production due to cost-effective materials and fabrication processes. Arguably, DSC ...

    • closedAccess   Surface Polarization Model for the Dynamic Hysteresis of Perovskite Solar Cells 

      Ravishankar, Sandheep; Almora Rodríguez, Osbel; Echeverría-Arrondo, Carlos; Ghahremanirad, Elnaz; Aranda Alonso, Clara; Guerrero, Antonio; Fabregat-Santiago, Francisco; Zaban, Arie; Garcia-Belmonte, Germà; Bisquert, Juan American Chemical Society (2017-02)
      The dynamic hysteresis of perovskite solar cells consists of the occurrence of significant deviations of the current density–voltage curve shapes depending on the specific conditions of measurement such as starting voltage, ...

    • openAccess   Tunable hysteresis effect for perovskite solar cells 

      Rong, Yaoguang; Hu, Yue; Ravishankar, Sandheep; huawei, liu; Hou, Xiaomeng; Sheng, Yusong; Mei, Anyi; Xu, Mi; Bisquert, Juan; Han, Hongwei Royal Society of Chemistry (2017-09-14)
      Perovskite solar cells (PSCs) usually suffer from a hysteresis effect in current–voltage measurements, which leads to an inaccurate estimation of the device e fficiency. Although ion migration, charge trapping/ detrapping, ...