Interview with Cherrelle, AATCC Member

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Hello Cherrelle, please introduce yourself and give us an overview of your work.

I am a PHD candidate in Chemical Engineering with a specialization in material science and nanotechnology, graduating in November of 2018. Specifically, my research focuses on sustainable energy, with a strong interest in improving the efficiency of nanocrystal-based solar cells. Looking ahead, I am working on publishing three research papers on the surface chemistry of copper indium diselenide and metal lead perovskite nanocrystals, exciton kinetics, and the thermal stability of the metal lead halide nanocrystals.

  

Cherrelle is preparing to dry a substrate on the Schlenk line using a 3-neck flask.

 What motivated you to specialize in nanocrystals?

Because Nanocrystals are cool! No, seriously they are! Nanocrystals can be used for a variety of applications and be composed of numerous different compositions. The nanocrystals can be engineered to have different properties from their bulk counterparts. In my research, nanocrystals allow us to engineer the bandgap to reach optimal performance.

What nanocrystals are you working with or hoping to work with in your current development of low cost photovoltaic devices (solar cells)?

 In my work, I work with copper indium diselenide (CuInSe2) and metal lead perovskite nanocrystal materials (MLHP).

What are the main opportunities or difficulties of synthesizing these nanocrystals? How are you hoping to improve the process?

The main challenge is to make nanocrystals stable under ambient conditions, isolate the desired crystal structure or composition, and to passivate the nanocrystals surfaces with ligands to mitigate the formation of surface traps.

One way to improve this is to understand the surface chemistry and synthetic routes of the nanocrystals and engineer ligand “cocktails” and the right reactants, to increase surface passivation and produce more of the desired crystals structures.

Where do you think their application will have the greatest potential?

In our lab, CuInSe2 are great materials for small applications, such as watches, due to our low efficiency. MLHP have demonstrated higher efficiencies and would be a great material for larger applications. However, research needs to be done to better understand the nanocrystal, especially in terms of stability and surface chemistry.

A major obstacle to wearable solar cells is conformal inflexibility, which limits the body’s range of motion. How do you think this can be solved?

Based on my understanding, there still needs to be research to better understand nanocrystal interface. As mentioned earlier, toxicity is a major concern because solar cells can involve reactive metals.

What qualities of nanocrystals would make them ideal/ not ideal for textile applications? How so?

Nanocrystals are very versatile: virtually just about any material can become a nanocrystal. Their size is small enough to be embedded in fibers. However, more research needs to be conducted on understanding how to effectively embed or woven into or with other textiles while maintaining their properties.

How far away are solar cells from being commercialized?

Actually, there are some already in the market for technical purposes. Some of the popular ones are silicon, copper indium, and gallium diselenide. Of course, research needs to be done to increase solar cells’ efficiency, stability, and flexibility so that they can be appropriate for wearable textile.

How efficient are the solar cells you are working with? Examples of what they’re able to power and for how long?

The solar cells I am currently working with have efficiencies of 1-3%. They can power simple calculators, watches, and a desk clock.

How can solar cells can be incorporated into technical/ apparel textiles?

Various layers, usually metals and glass, are necessary to separate electron and hole pairs and generate current. The glass layer can be replaced with a textile material, plastics or nanocellulose. Currently, solar panels with higher efficiencies are constructed on rigid substrates and more flexible devices have lower efficiencies.

Thank you for sharing your thoughts on the future of solar cells application, particularly in the realm of textiles.

Opinions expressed in this blog post are those of the author and not necessarily those of AATCC