24 Sep, 2019 (Tue)Time:
SpeakerProf. Lioz Etgar,
The Hebrew University of Jerusalem, The Institute of Chemistry, Casali Center for Applied Chemistry, Jerusalem, Israel
Photovoltaic cells (PVCs) use semiconductors to convert sunlight into electrical current and are regarded as a key technology for a sustainable energy supply. The 1st and 2nd generations of PV technology were based on bulk semiconductor solids, accompanied by a relatively high manufacturing cost. The 3rd generation of PV cells, developed over the past two decades, differ from previous cells in that they don’t necessarily rely only on a traditional single p-n junction configuration. Instead, they are configured as donor-acceptor (D-A) hetero-junctions, with staggered electronic band alignment. These 3rd generation PV cells also carry a lower manufacturing cost.
Recent discoveries have revealed a breakthrough in the field using inorganic-organic hybrid layers called perovskites as the light harvester in the solar cell. The inorganic-organic arrangement is self-assembled as alternate layers, being a simple, low cost procedure. These organic-inorganic hybrids promise several benefits not delivered by the separate constituents. This work will discusses new directions related to perovskite and their applications in solar cells.
In low dimensional systems, stability of excitons in quantum wells is greatly enhanced due to the confined effect and the coulomb interaction. The exciton binding energy of the typical 2D organic-inorganic perovskites is up to 300 meV and their self-assembled films exhibit bright photoluminescence at room temperature.
- In this work we will show the dimensionality in the perovskite structure. The 2D perovskite structure should provide stable perovskite structure compare to the 3D structure. The additional long organic cation, which is added to the perovskite structure (in the 2D structure), is expected to provide hydrophobicity, which will enhance the resistivity of the perovskite to humidity. Moreover we will demonstrate the use of 2D perovskite in high efficiency solar cells.
- Moreover, we will show a highly efficient semitransparent perovskite solar cell. The semitransparency was achieved through a mesh assisted evaporation technique when a grid of perovskite is created on the TiO2 The perovskite grid allows to get controlled semitransparent perovskite solar cell.
- Organic-inorganic halide perovskite is used mainly in its “bulk” form in the solar cell. Confined perovskite nanostructures could be a promising candidate for efficient optoelectronic devices, taking advantage of the superior bulk properties of organo-metal halide perovskite, as well as the nanoscale properties. In this talk, I will present our recent progress related to the synthesis and characterization of perovskite NPs- i.e. Inorganic and hybrid organic-inorganic NPs. New nanostructures such us: NRs and NWs will be presented and the introduction of other cations such us Rb will be shown.
Biography of the speaker:
Prof. Lioz Etgar obtained his Ph.D. (2009) at the Technion–Israel Institute of Technology and completed post-doctoral research with Prof. Michael Grätzel (the inventor of the dye sensitized solar cells and a leader in the photovoltaic field, 2009–2012) at EPFL, Switzerland. In his post-doctoral research, he received a Marie Curie Fellowship and won the Wolf Prize for young scientists. Since 2012, he has been a senior lecturer in the Institute of Chemistry at the Hebrew University. On 2017 he became an Associate Professor at the Hebrew University. Recently Prof. Etgar won the prestigious Krill prize by the Wolf foundation. He has more than 80 publications, 7 patents and 6 book chapters.
Prof. Lioz Etgar’s research is focused on the development of innovative solar cells. Prof. Etgar’s group is searching for new excitonic solar cell architectures while designing and controlling the inorganic light harvester structure and properties, in order to improve the photovoltaic parameters.
A recent major breakthrough in solar cell technology was the discovery of a novel material called perovskite. To date, solar cells based on perovskite are already delivering greater efficiency than current solar cell technologies. Prof. Etgar was the first to use perovskite in a much simpler solar cell configuration that reduces the cost of solar cells and improves their stability. This resulted in a pioneer publication in the field with more than 1500 citations in 6 years.
OrganizerProf. W.C.H. Choy
Most seminars are open to the general public, free of charge, unless otherwise stated. Registration is not required. Arrangement for car parking facilities on campus please contact us for details.
For enquiries, please contact:
Department of Electrical and Electronic Engineering,
Room 601, Chow Yei Ching Building,
Pokfulam Road, Hong Kong
Tel: (852) 3917 7093