Synthesis of perovksite nanocrystals and related applications
The high demand for energy consumption in everyday life activities, at the same time with the fears of climate change are driving the scientific community to explore novel materials for efficient energy conversion and storage. Perovskites, a prominent category of materials, including metal halides and perovskite oxides hold a significant role among energy materials, which can effectively replace the conventional ones. The simultaneously need for new energy materials together with the increasing interest for making new devices and even exploring new physics, thrust the research to control the structuring of the perovskite materials at the nanoscale. Nanostructuring of the perovskites due to their reduced dimensions are advantageous in offering large surface area, extensive porous structures, controlled transport and charge-carrier mobility, strong absorption and photoluminescence and confinement effects. These features together with the unique tunability in composition, shape and functionalities make the perovskite nanocrystals, uniquely suited for efficient energy-related applications such as photovoltaics, catalysts, thermoelectrics, batteries, supercapacitors and hydrogen storage systems.
All-inorganic metal-halide perovskite nanostructures in liquid form or/and directly deposited on substrates
The research of our group is mainly focus on the development of all-inorganic metal halides. These semiconducting nanocrystals exhibit a completely different behavior from their bulk materials of the same stoichiometry due to quantum confinement effects. Optical/electronic properties can be affected in an unexpected way from the size/shape particle modifications. Their fascinating properties together with their colloidal form make these materials ideal candidates for application in energy-related applications.
Wet chemistry approaches have been used for the synthesis of perovskite nanostructures in centrosymmetric or non-centrosymmetric morphologies (spherical particles, nanoplatelets, nanosheets or more complex structures). These approaches have been carefully selected because they can allow developing finely size-, shape-, and composition- tailored nanocrystals by careful regulation of thermodynamically/kinetically driven growth processes in the liquid phase.
The perovskite nanocrystals synthesized with wet chemistry methods are well crystalline and dispersed in organic solvents as they covered with organic ligands. They exhibit very high quantum yields, narrow line width and high stability. Their emission could cover the whole visible range by modifying their composition, morphology and size. Anion exchange processes (chemically or laser-triggered) have been utilized for the spectral tuning through partial or complete replacement of anion in a solution. In the anion exchange procedures, the initial lattice and shape of the nanocrystals are retained.
Perovskite nanostructures covered by organic molecules or free of ligands have been grown in colloidal solutions and then deposited on substrate or grown directly on it. Their structural features together with their physical properties have been carefully investigated and the impact of the structure, morphology, and composition on energy device performance have been evaluated.
Low-temperature Benchtop-synthesis of All-inorganic Perovskite Nanowires
A. Kostopoulou, M. Sygletou, K. Brintakis, A. Lappas and E. Stratakis, Nanoscale, 2017, 9, 18202-18207
Perovskite nanostructures for photovoltaic and energy storage devices
A. Kostopoulou, E. Kymakis and E. Stratakis, J. Mater. Chem. A, 2018, 6, 9765-9798
Dr Emmanuel Stratakis
Dr Athanasia Kostopoulou
Dr Konstantinos Brintakis
Dr Maria Sygletou
Dr Dimitra Vernardou