לוח שנה משולב

Driven by recent technological advancements, behavior and brain activity can now be measured at an unprecedented resolution and scale. This “big-data” revolution is akin to a similar revolution in biology. In biology, the wealth of data allowed systems-biologists to uncover the underlying design principles that are shared among biological systems. In my studies, I apply design principles from systems-biology to cognitive phenomena. In my talk I will demonstrate this approach in regard to creative search. Using a novel paradigm, I discovered that people’s search exhibits exploration and exploitation durations that were highly correlated along a line between quick-to-discover/quick-to-drop and slow-to-discover/slow-to-drop strategies. To explain this behavior, I focused on the property of scale invariance, which allows sensory systems to adapt to environmental signals spanning orders of magnitude. For example, bacteria search for nutrients, by responding to relative changes in nutrient concentration rather than absolute levels, via a sensory mechanism termed fold change detection (FCD). Scale invariance is prevalent in cognition, yet the specific mechanisms are mostly unknown. I found that an FCD model best describes creative search dynamics and further predicts robustness to variations in meaning perception, in agreement with behavioral data. These findings suggest FCD as a specific mechanism for scale invariant search, connecting sensory processes of cells and cognitive processes in human. I will end with a broader perspective and outline the benefits of the search for computational design principles of cognition.

Mixing semi-dilute solutions of oppositely charged polyelectrolytes generally yields compositions spanning complexes (solid) to coacervates (elastic liquid) to dissolved solutions with increasing salt concentration. In this work we show how to form a strong network of oppositely charged polyelectrolytes by using an interplay of hydrogen, hydrophobic, and electrostatic interactions.

3D halide perovskites have emerged as a new class of semiconductors, but some basic optoelectronic properties of 3D bulk halide perovskites are still shrouded in mystery. The talk will start from a simplified representation of the halide perovskite lattice allowing to progressively account for various advanced topics.

Halide (hybrid) perovskites (HaP) have emerged as a new class of semiconductors that truly encompass all the desired physical properties for building optoelectronic and quantum devices such as large tunable band-gaps, large absorption coefficients, long diffusion lengths, low effective mass, good mobility and long radiative lifetimes. In addition, HaPs are solution processed or low-temperature vapor grown semiconductors and are made from earth abundant materials thus making them technologically relevant in terms of cost/performance. As a result, proof-of-concept high efficiency optoelectronic devices such as photovoltaics and LEDs have been fabricated. In fact, photovoltaic efficiencies have sky rocketed to 23% merely in the past five years and are nearly on-par with mono-crystalline Si based solar cells. Such unprecedented progress has attracted tremendous interest among researchers to investigate the structure-function relationship and understand as to what makes Halide hybrid perovskites special?
In my talk, I will attempt to answer some of the key questions and in doing so share the results from our work on HaPs over the past four years in understanding structure induced properties of HaPs. I will also highlight fundamental bottlenecks that exist going forward which present opportunities to create platforms to understand the interplay between light, fields and structure on the properties of perovskite-based materials.