Barlow

Narrow-Band Electrochromism of Ferrocene-Substituted Rhodamine B

Daniel Morton — Tue, 29 Jul 2025 19:54:28 +0000

Narrow-Band Electrochromism of Ferrocene-Substituted Rhodamine B Daniel Morton Tue, 07/29/2025 - 13:54

CHEMISTRY OF MATERIALS, 2025, 37, 15, 5558-5568

Off

Traditional

White

Electrolyte Immersion Increases Photoconductivity in a Model Polymer Photocathode

Daniel Morton — Mon, 28 Jul 2025 19:41:39 +0000

Electrolyte Immersion Increases Photoconductivity in a Model Polymer Photocathode Daniel Morton Mon, 07/28/2025 - 13:41

ACS ENERGY LETTERS, 2025, 10, 4019-4026

Off

Traditional

White

Too Fast for Spin Flipping: Absence of Chirality-Induced Spin Selectivity in Coherent Electron Transport through Single-Molecule Junctions

Daniel Morton — Wed, 02 Jul 2025 19:10:43 +0000

Too Fast for Spin Flipping: Absence of Chirality-Induced Spin Selectivity in Coherent Electron Transport through Single-Molecule Junctions Daniel Morton Wed, 07/02/2025 - 13:10

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, 147, 28, 25043-25051

Off

Traditional

White

Electricity, Air, and Plastic Recycling

Daniel Morton — Tue, 17 Jun 2025 21:15:48 +0000

Electricity, Air, and Plastic Recycling Daniel Morton Tue, 06/17/2025 - 15:15

Daniel Morton

This collaboration between four RASEI Fellows shows how electricity can be used to impart ‘superoxide powers’ to oxygen gas molecules from air, enabling the efficient recycling of PET plastics.

In 2012, 32.5 million tons of plastic waste was produced globally. 4.5 million tons of which was poly(ethylene terephthalate), better known as PET. You likely know this as the plastic that has the number 1 in the middle of the recycling symbol. PET is used extensively in materials such as packaging, textiles, films, and flexible electronics. By far and away its main use is in bottled drinks. PET is considered a standout material, it is strong, chemically resistant, transparent, and impermeable to water. Even better, it is possible to recycle PET – it has its own number, right? Unfortunately, this is not quite the full story. Globally, it is estimated that only about 9% of plastic waste is recycled, and while PET waste is one of the best performers, with a recycling rate approaching between 25-30%, the majority of plastic, even PET, ultimately ends up in landfills, incinerated, or worse, polluting our environment. The magnitude of this problem is only increasing; in 2024 the world generated an estimated 240 million tons of plastic waste, representing more than eight-fold increase in 12 years and highlighting the need for more effective solutions.

This teams bring together four RASEI Fellows, Oana Luca (Chemistry, CU Boulder), Seth Marder (Chemistry and Chemical & Biological Engineering, CU Boulder), Stephen Barlow (RASEI, CU Boulder) and Elisa Miller (Chemistry and Nanoscience, NREL) to address the accelerating issue of plastic waste. While there are many parts to this global challenge, this research focuses on how we recycle plastics, specifically PET. When we think about recycling plastic, most of us just think about throwing a plastic bottle, or piece of packaging, into a recycling bin. We rarely give it much thought after that. This really is just the start of a journey that is more complex than many realize. There are actually several different approaches to giving plastic a second life. The most common, and perhaps the method that most people are familiar with, is mechanical recycling.

Think of mechanical recycling like an industrial washing machine combined with a paper shredder. Plastic items are collected, sorted, cleaned, and then chopped up into small flakes or melted down into pellets that can be molded into new products. This approach is efficient and works great for clean, single-type plastics, but there are some significant limitations with this process. In the same way that a white shirt can’t be perfectly restored after being mixed with brightly colored laundry, plastic quality degrades each time it goes through mechanical recycling. This reduction in quality is stark, most mechanically recycled plastics can only go through the process 2-3 times before they become unusable. This makes it financially unattractive and severely limits the long-term efficacy of recycling. How can this be an enduring solution if we can only recycle something a couple of times?

Chemical recycling takes a very different route, instead of the ‘brute-force’ approach of just melting and reshaping the plastic, it employs a more surgical method, breaking down the plastic polymer chains into their constituent molecular building blocks. These molecular building blocks can then be used, either to make new plastics, or for other applications. Because the new plastics are made with molecular control, there is no degradation in quality, and the materials can be recycled over and over, essentially as many times as you wish. Instead of a washing machine combined with a paper shredder, this is more like a LEGO set, where the model can be taken apart brick by brick and be used to build something entirely new. This research describes a new approach to depolymerization, a class of chemical recycling.

The research described in this RASEI collaboration, just published in ACS Sustainable Chemistry and Engineering, offers a new, more efficient approach. By passing an electric charge through the reaction, electrons can be used to activate molecules that can then go on to react with the polymer. In a recent study, that used additive molecules as electron shuttles, the team observed the addition of electrons to oxygen gas molecules in small amounts present in the reaction, that were originally thought to be innocent bystanders in the mixture. This led the team to hypothesize that oxygen gas molecules, directly from air, could be chemically reduced, (that is that they take on an extra electron), leading to the formation of a relatively stable superoxide radical anion, O₂^·–. This activated superoxide now acts in place of the solvent and reacts directly with the polymer. Since the superoxide has an extra electron gained from the electric current, the negatively charged superoxide molecule reacts with the centers that have a positive charge on the polymer. This results in the breaking down of the polymer in a predictable and selective fashion, and the incorporation of oxygen into the building blocks instead of the solvent molecules, leading to the reliable and reproducible formation of the same molecules that were used to build the polymer in the first place. The LEGO bricks are formed cleanly and are ready to be used again, with no degradation in molecular quality. This work demonstrates this technology on a range of different plastics using air, arguably one of the most abundant and cheap reagents, as the primary oxygen source, and all done at room temperature and pressure, a huge improvement on other chemical recycling approaches. While the results are promising and show good efficiencies, this lab-based proof of principle still has a number of challenges to solve before it can be scaled up to meaningful levels.

Today, most plastics are recycled using mechanical recycling, which is like the combination of an industrial washing machine and a paper shredder, producing low-quality products and reducing the possibility of future recycling, leading many to explore chemical recycling as an alternative to gain access to more valuable chemical building blocks. Current mainstream chemical recycling methods are like using a sledgehammer, they typically require high temperatures and lots of energy to break the chemical bonds. The development of electrochemical methods offers a more controlled approach, breaking down plastics at the molecular level and reliably producing build blocks that can be used over and over again. New recycling technologies could transform how we handle plastic waste, opening the door to recycling previously un-recyclable plastics, doing it in a more energy efficient way, producing higher quality recycled plastics, and making recycling economically competitive with virgin plastic production from oil. The development of more effective and general recycling strategies isn’t just an environmental imperative. As plastic waste continues to accumulate, it is rapidly becoming an economic necessity. We already have so much plastic in the world, if we can develop methods to regenerate and reuse the building blocks from plastic waste it will turn landfills into gold mines.

How amazing would it be if instead of society wasting plastics, filling landfills, and polluting our environments, we viewed used plastics as a commodity for future applications?

June 2025

Off

Traditional

White

Diamine Surface Passivation and Postannealing Enhance the Performance of Silicon-Perovskite Tandem Solar Cells

Daniel Morton — Tue, 17 Jun 2025 17:42:23 +0000

Diamine Surface Passivation and Postannealing Enhance the Performance of Silicon-Perovskite Tandem Solar Cells Daniel Morton Tue, 06/17/2025 - 11:42

ACS APPLIED MATERIALS & INTERFACES, 2025, 17, 26, 38754-38762

Off

Traditional

White

Polymer nanoparticle photocatalysts realized in non-aqueous solvents

Daniel Morton — Thu, 22 May 2025 21:57:02 +0000

Polymer nanoparticle photocatalysts realized in non-aqueous solvents Daniel Morton Thu, 05/22/2025 - 15:57

SUSTAINABLE ENERGY & FUELS, 2025, 9, 14, 3796-3807

Off

Traditional

White

Elucidating Charge Carrier Reactivity, Conversion, and Degradation in n-Doped Oligo- and Poly(benzodifurandione)

Daniel Morton — Wed, 21 May 2025 21:46:49 +0000

Elucidating Charge Carrier Reactivity, Conversion, and Degradation in n-Doped Oligo- and Poly(benzodifurandione) Daniel Morton Wed, 05/21/2025 - 15:46

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2025, 147, 22, 19372-19379

Off

Traditional

White

Scientists move microscopic solar chemical factories out of water to unlock new transformations

Daniel Morton — Wed, 07 May 2025 16:42:05 +0000

Scientists move microscopic solar chemical factories out of water to unlock new transformations Daniel Morton Wed, 05/07/2025 - 10:42

Daniel Morton

Find out more

Read the Article

Four RASEI Fellows work together to expand the potential applications of nanoparticle photocatalysts

We all understand the power of the sun. We feel it on a hot summer’s day, we see it harnessed in solar panels that power our homes and cities. Chemical photocatalysis develops approaches to shrink that ability to harness this energy down to a molecular scale, and uses this energy to power chemical reaction, to power the building of important organic molecules, the foundations of pharmaceuticals, materials, and clean fuels.

One of the technologies used to harness light on the molecular level are a class of particles called organic nanoparticles (oNPs). Think of them as tiny, solar-powered factories, expertly designed to capture light and use its energy to drive chemical reactions. The oNPs are made from readily available earth-abundant materials, offering a cheap, clean, and sustainable alternative to a range of more traditional chemical reactions, which can often rely on rare, expensive metals that are hard to get hold of and can produce significant waste.

However, the oNPs, for all their potential as chemical factories, do have one significant limitation, they can only be built and operated in water. This is a fundamental roadblock. While water is essential for life, it is often a very poor environment for performing chemical reactions and can be very detrimental for the complex and delicate sequence of chemical transformations required for producing valuable products. The full power of these nano-factories was, quite literally, stuck in the water.

To understand this challenge, imagine that you have designed the world’s most efficient and powerful engine. It is a true engineering breakthrough, but it comes with a major catch, it can only run while completely submerged in the ocean. This is fine if you want to get around in a submarine, or a boat, but you can’t put it into a car, or a plane, or a generator on land, where you need it most. The potential of this new innovation is trapped, unable to be used for countless valuable applications.

That is similar to the situation faced by the researchers, led by RASEI Fellows Stephen Barlow, Seth Marder, Obadiah Reid and Garry Rumbles. The oNPs were confined to water-based reaction media, in order to realize their full potential the team needed to find a way to move these delicate ‘nano-factories’ from water to the ‘dry-land’ of other chemical environments, known as non-aqueous solvents, without the oNPs collapsing or breaking down.

This study describes a solution that the team developed. They devised a multi-step process to gently coax the oNPs out of their native water environment and prepare them to operate in different chemical solvents.

The process they developed is analogous to making salad dressing in the kitchen. It begins by mixing the water containing the nanoparticles with an oily substance (in this study oleic acid) and shaking it. This creates an emulsion, where tiny droplets of water are suspended in the oil, much like a vinaigrette. During this process the oNPs leave the water and move into the oil, which wraps around them like a protective coating. Finally the water is gently remove, leaving the oNPs safely suspended in their new oily environment. The protective layer formed around them allows them to be seamlessly transferred to a range of new non-aqueous solvents, ready to get to work.

A key part of this study was demonstrating that the oNP ‘factories’ were still functional after their transfer to new solvent systems. Using a suite of tools the team were able to confirm that the transferred oNPs could still absorb light and perform the chemical reactions.

With these findings the potential of the oNPs can be explored and expanded. It reveals new opportunities, not only in putting together organic molecules, but also in the synthesis of clean fuels, such as hydrogen.

MAY 2025

Off

Traditional

White

Air-Enabled Electricity-Driven Depolymerization of Polyesters

Daniel Morton — Sun, 13 Apr 2025 19:26:24 +0000

Air-Enabled Electricity-Driven Depolymerization of Polyesters Daniel Morton Sun, 04/13/2025 - 13:26

ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 2025, 13, 16, 5818-5827

Off

Traditional

White

Dimensionality-Controlled Confinement Effects for Tunable Optoelectronic Properties in Quasi-1D Hybrid Perovskites

Daniel Morton — Tue, 25 Mar 2025 19:40:43 +0000

Dimensionality-Controlled Confinement Effects for Tunable Optoelectronic Properties in Quasi-1D Hybrid Perovskites Daniel Morton Tue, 03/25/2025 - 13:40

ACS NANO, 2025, 19, 13, 12895-12909

Off

Traditional

White