Presentation Title: Impedance spectroscopy analysis of the physical response of perovskite solar cells
Prof. Juan Bisquert presented this talk in the webinar on Nanomedicine, Nanomaterials and Nanotechnology organized by Vebleo
Affiliation: Institute of Advanced Materials, Universitat Jaume I, Castelló, Spain
Biography
Juan Bisquert is a professor of Applied Physics at Universitat Jaume I de Castelló. He is the director of the Institute of Advanced Materials, that develops research on materials, nanostructures and devices for production and efficient use of clean energies. He published 400 papers in research journals, and authored a series of books, including The Physics of Solar Energy Conversion (CRC Press, 2020). He has 30000 citations and h-index 97.
Prof. Juan Bisquert is a Senior Editor of the Journal of Physical Chemistry Letters. He has been distinguished in the list of Highly Cited Researchers from 2014 to 2019. The research activity of Juan Bisquert has been focused on materials and devices for production and storage of clean energies, in particular photovoltaic devices, based on nanostructured metal oxides, semiconductor quantum dots, organic and hybrid semiconductors, and related applications such as luminescence.
The main contribution of Juan Bisquert by which he established an international reputation is the application of measurement techniques and physical modeling in several areas of energy devices, relating the device operation with the elementary steps that take place at the nanoscale dimension: charge transfer, carrier transport, chemical reaction, etc., especially in the field of impedance spectroscopy, as well as device models, and the development of a general physical picture of solar energy devices. Since 2014, the research field has been largely influenced by the discovery of a new class of photovoltaic materials and devices, generally termed hybrid perovskites.
These materials show excellent performance and radically new semiconductor properties. Unraveling the mechanisms of perovskite solar cells has established scientific work of high impact by Bisquert and coworkers in the last few years.
Abstract
The dynamic response of metal halide perovskite devices shows a variety of physical responses that need to be understood and classified for enhancing the performance and stability and for identifying new physical behaviours that may lead to developing new applications. These responses are the outcome of complex interactions of electronic and ionic carriers in the bulk and at interfaces. Based on a systematic application of frequency modulated techniques and time transient techniques to the analysis of kinetic phenomena, we present a picture of the dominant effects governing the kinetic behaviour of halide perovskite devices.
First with impedance spectroscopy we provide an interpretation of capacitances as a function of frequency both in dark and under light, and we discuss the meaning of resistances and how they are primarily related to the operation of contacts in many cases. Working in samples with lateral contacts, we can identify the effect of ionic drift on changes of photoluminescence, by the creation of recombination centers in defects of the structure. We also address new methods of characterization of the optical response by means of light modulated spectroscopy.
The IMPS is able to provide important influence on the measured photocurrent. We apply the dynamic picture to the characterization of perovskite memristors. A memristor is a device that has different metastable states at a voltage V.
It has a resistance that depends on the history of the system, and the states can be switched by applied voltage. It is simpler than a transistor in that the control occurs by 2 contacts. As a summary we suggest an interpretation of the effects of charge accumulation, transport, and recombination, how these effects influence the current-voltage characteristics and time transient properties, and we suggest a classification of the time scales for ionic/electronic phenomena in the perovskite solar cells.
This talk was delivered in the webinar organized by Vebleo