A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics

Cost management and toxic waste generation are two key issues that must be addressed before the commercialization of perovskite optoelectronic devices. We report a groundbreaking strategy for eco-friendly and cost-effective fabrication of highly efficient perovskite solar cells. This strategy involves the usage of a high volatility co-solvent, which dilutes perovskite precursors to a lower concentration (<0.5 M) while retaining similar film quality and device performance as a high concentration (>1.4 M) solution. More than 70% of toxic waste and material cost can be reduced. Mechanistic insights reveal ultra-rapid evaporation of the co-solvent together with beneficial alteration of the precursor colloidal chemistry upon dilution with co-solvent, which in-situ studies and theoretical simulations confirm. The co-solvent tuned precursor colloidal properties also contribute to the enhancement of the stability of precursor solution, which extends its processing window thus minimizing the waste. This strategy is universally successful across different perovskite compositions, and scales from small devices to large-scale modules using industrial spin-coating, potentially easing the lab-to-fab translation of perovskite technologies.

Application of Colloids and Its Relevance in Mineral Engineering

Mineral engineering is an interdisciplinary branch which includes many branches like physics, chemistry, math and sub branches like instrumentation, chemical engineering, mechanical engineering, geology etc. Amongst the various separation/beneficiation techniques of mineral processing, froth flotation is one of the most important fines beneficiation technique, which depends upon the surface and colloid chemical phenomena as the basis of selectivity. The method of separation relies on the surface state and colloidal chemistry of the ore particles and chemical reagents. Adsorption at the mineral solution interface is of major importance for the behaviour of mineral particles in the solution and for successful flotation performance. Adsorption of simple ions determine the change of the particle surface and electrochemical properties of the pulp/slurry phase and therefore affect the colloidal stability and the adsorption behaviour of reagent on the mineral surface. This chapter describes in detail about the role, importance and application of colloidal chemistry in mineral processing especially froth flotation. Froth flotation will remain a key unit operation for the treatment of low-grade ore fines for the decades to come with the overarching challenge as the need of the hour is to modify and improve existing process conditions so as to maintain an acceptable grade and recovery response for the feed whose liberation is more finer, more complex association of minerals and of lower grade.

Application of the principles of colloidal chemistry to obtain the purest preparation of tetanotoxin

If you take a broth culture of a tetanus bacillus and filter it through a Chamberland'a candle, then, as you know, you will get a completely transparent, sterile liquid with pronounced toxic properties.

Developing the Chemistry of Colloidal Cu Nanocrystals to Advance the CO2 Electrochemical Reduction

The ability to tailor make materials with atomic scale precision is crucial for understanding the sensitivities of their performance parameters and for achieving the design specification corresponding to optimal device operation. Herein, this topic is discussed in the context of catalysis. The electrochemical CO2 reduction reaction (CO2 RR) holds the promise to close the carbon cycle by storing renewable energies in chemical feedstocks, yet it suffers from the lack of efficient and selective catalysts. This article highlights how colloidal chemistry can contribute to tackle this compelling issue by designing shape-controlled nanocatalysts. In particular, two case studies relative to copper nanocrystals are discussed.

Crystal and electronic facet analysis of ultrafine Ni2P particles by solid-state NMR nanocrystallography

Structural and morphological control of crystalline nanoparticles is crucial in the field of heterogeneous catalysis and the development of “reaction specific” catalysts. To achieve this, colloidal chemistry methods are combined with ab initio calculations in order to define the reaction parameters, which drive chemical reactions to the desired crystal nucleation and growth path. Key in this procedure is the experimental verification of the predicted crystal facets and their corresponding electronic structure, which in case of nanostructured materials becomes extremely difficult. Here, by employing 31P solid-state nuclear magnetic resonance aided by advanced density functional theory calculations to obtain and assign the Knight shifts, we succeed in determining the crystal and electronic structure of the terminating surfaces of ultrafine Ni2P nanoparticles at atomic scale resolution. Our work highlights the potential of ssNMR nanocrystallography as a unique tool in the emerging field of facet-engineered nanocatalysts.

INTERPHASE OF BUILDING COMPOSITIONS

Целью данной работы является демонстрация нескольких методологических подходов к решению задач управления процессами трансформационных превращений вещества на границе раздела фаз макроповерхности и в дисперсных системах, которые можно, на наш взгляд, использовать в качестве критериев количественной характеристики одного из основополагающих законов научного направления «Геоника» - закона «Сродства структур». Предложенные подходы базируются на фундаментальных положениях физической и коллоидной химии, кристаллоэнергетики. В качестве данных критериев, позволяющих управлять структурообразованием на межфазной границе, предложены энергетическая интерпретация кинетической модели топохимического взаимодействия компонентов и значение аналоговой постоянной Гамакера. Разработаны методологические принципы экспериментального определения этих характеристик. Проведена апробация предложенных подходов на примере различных тонкодисперсных композиций: глиоксаль-кора, базальт-кора, базальт-полиминеральный кварцево-полевошпатовый песок и базальт-сапонит. Кроме того, коллоидно-химический подход к созданию суспензий на основе тонкодисперсных частиц горных пород, обладающих специфическими свойствами, позволяет синтезировать агрегативно устойчивые суспензии магнитных жидкостей. Приводятся примеры их использования в строительном материаловедении. This work aims to demonstrate several methodological approaches to solving problems of controlling the transformation processes of matter at the interface of the macro-surface and in dispersed systems, which, in our opinion, can be used as criteria for the quantitative characteristics of one of the fundamental laws of the scientific direction "Geonics" - the "Affinity of structures" law. The proposed approaches are based on the fundamental principles of physical and colloidal chemistry, crystal energy. The energy interpretation of the kinetic model of the topochemical interaction of thecomponents and the analog Hamaker constant value are proposed as these criteria make it possible to control the structure formation at the interface. We have developed the methodological principles for the experimental determination of these characteristics. We have tested the proposed approaches on various finely dispersed compositions: glyoxal-bark, basalt-bark, basalt-polymineral quartz-feldspar sand, and basalt-saponite. Besides, the colloidal-chemical approach to the creation of suspensions based on finely dispersed particles of rocks with specific properties makes it possible to synthesize aggregately stable suspensions of magnetic fluids. Examples of their use in building materials science are given.

Global multi-method analysis of interaction parameters for reversibly self-associating macromolecules at high concentrations

Weak macromolecular interactions assume a dominant role in the behavior of highly concentrated solutions, and are at the center of a variety of fields ranging from colloidal chemistry to cell biology, neurodegenerative diseases, and manufacturing of protein drugs. They are frequently measured in different biophysical techniques in the form of second virial coefficients, and nonideality coefficients of sedimentation and diffusion, which may be related mechanistically to macromolecular distance distributions in solution and interparticle potentials. A problem arises for proteins where reversible self-association often complicates the concentration-dependent behavior, such that grossly inconsistent coefficients are measured in experiments based on different techniques, confounding quantitative conclusions. Here we present a global multi-method analysis that synergistically bridges gaps in resolution and sensitivity of orthogonal techniques. We demonstrate the method with a panel of monoclonal antibodies exhibiting different degrees of self-association. We show how their concentration-dependent behavior, examined by static and dynamic light scattering and sedimentation velocity, can be jointly described in a self-consistent framework that separates nonideality coefficients from self-association properties, and thereby extends the quantitative interpretation of nonideality coefficients to probe dynamics in highly concentrated protein solutions.