Iran-China-Germany
Virtual Symposium
on
Nanoscience and Nanotechnology
Speech Details
Official collaborations in science and technology, especially on Nanotechnology, have been recently initiated between Iran ,China and Germany. Many effective programs have been launced in this regard. This event aims to initiate and promote scientific collaboration between Iran ,China and Germany scientists. We propose to organize and run this event by the consortium of 5 top Iranian Universities of Technology (UT5), in order to facilitate direct contact of the leading scientists of these universities with their Chinese and Germans counterpart.
Speakers
Title: The Schroedinger equation: Where it works and where it doesn’t.
Abstract: According to the postulates of quantum mechanics, any kind of matter is described by a wave function which can be determined using the Schroedinger equation. Quantum chemists have applied this equation since decades in order to describe the electronic structure of a large variety of substances with high accuracy. What about chemical reactions as determined by nuclear motion? It turns out that the Schrodinger equation is not equally successful in describing nuclear motion. Instead, using Newton dynamics leads to a simple and convincing picture. Hence an additional postulate of quantum mechanics must read: Nuclear motion is classical. Numerical examples are presented and philosophical consequences are discussed.
Title: Flexible and ultralight perovskite solar cell
Abstract:
Organic-inorganic hybrid perovskite materials have received extensive attention due to their excellent photoelectric properties in the past decades. It is worth noting that perovskite materials are flexible, and the light absorber layers can be fabricated in large areas by low temperature solution method, which is an ideal material for flexible solar cells. Since the first report in 2013, the certified efficiency of flexible perovskite solar cells has also increased from 2.9% to 23.35%, but there still have a gap compared with rigid devices. This is mainly due to the optical characteristics of flexible substrates and the limitations of device fabrication temperature. Recently, we have improved the conductivity of SnO2 electron transport layer by vacuum assisted low temperature annealing. Based on this method, we successfully realized a flexible perovskite solar cell with an efficiency of 20.14% on PET/ITO substrate. We have used organic downshifting fluorescent materials optimize the spectral response of flexible perovskite solar cells. Compared with reference devices, the integrated current density is increased from 22.73 mA/cm2 to 23.26 mA/cm2, and the device efficiency is increased from 22.19% to 22.81%. We have used high temperature resistant and transmittance ultra-thin flexible substrate improves the efficiency and mechanical stability of flexible perovskite solar cells. The ultra-thin flexible perovskite solar cell based on PI substrate achieved the efficiency of 23.04%, and there was no crack on the surface of the perovskite film after 100 times of extreme bending tests with a bending radius of 1 mm.
Title: An Introduction to Materionic Engineering
Abstract:
Advances in materials science and electronic engineering, especially in the overlapping subjects and phenomena, have inspired the introduction of a new term for researchers in these fields to conduct a common dialogue throughout the world. The new term is Materionic Engineering or Materionics, taken from the first and second halves of the two words “materials” and “electronics,” respectively. With the introduction of Materionics, once it has flourished, we expect that a new wave of understanding will engulf and overtake the scholars of this new field and that their contributions in the disciplines having overlaps will be most synergistic. Inevitably, goods and services that Materionics could yield will rapidly become universal in modern life and civilization.
Title: O-E Properties of Controlled Reduced Graphene Oxide IR-absorber Prepared by Green and Facile Routes for fabricated thin film superconducting bolometers
Abstract:
To increase the response of IR superconducting bolometric detectors, high absorption graphene based leyers were developed. Graphene oxide (GO) dispersion was prepared based on improved Hummer’s method. The reactants concentration were optimized through microwave pretreatment of graphite flakes and controlling the amount of KMnO4 and concentrated sulfuric acid. The approach resulted in homogeneous multilayer self-standing thin films, composed of stacked reduced graphene oxide (rGO) planes. The developed films were characterized by Raman, FESEM, Four-point probe versus temperature, and FTIR techniques. Raman spectrum of the prepared samples show G bands shift towards lower wavenumbers compared to the G bands of the GO which is associated to a lower content of oxygen in the rGOs. Also, the intensity ratio between D band and G band (ID/IG) shows the number of surface defects is small. The FESEMs of the samples show the flat, smooth sheet-like surface with few wrinkles and no folding of rGO was observed. Also the cross-section image verifies the multi-stacking layer structure. The electrical resistance vs. temperature implies semiconductive behavior with pure resistive and in-plane conductivity in the rGOs. The FTIR spectrum of the samples, measured in the wavelengths range of 2.5 to 25 µm, shows above 93% high absorption, making the developed materials a good candidate as for sensitive detectors in the infrared range. The high temperature superconductive bolometric detectors have been designed and fabricated using superconductive YBCO thin films. The films have been developed by a combination of magnetron sputtering and/or MOD techniques on various engineered crystalline substrates such as SrTiO3 and LaAlO3 substrates. In this presentation, optimization of detectivity with respect to geometrical parameters for free standing membrane type superconductor edge transition sensors is reviewed, and the detectivity versus the free standing substrate thickness with and without the absorber and modulation frequency is presented. Based on the theoretical results optimum device geometry for high detectivity is obtained and several bolometers with different geometries are fabricated. The results on detectors made using YBCO films prepared by Metal Organic Deposition (MOD) process will also be presented. The optical responsivity and voltage noise of the bolometers are measured versus modulation frequencies up to 100KHz. Using the measurement results, the corresponding detectivity of the fabricated devices is obtained versus modulation frequency and device geometry.
