chemistry

Non-fullerene acceptor

Non-fullerene acceptor is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Non-fullerene acceptor rather than just read about it. In short: Non-fullerene acceptors (NFAs) are types of acceptors used in organic solar cells (OSCs). The name Fullerene comes from another type of acceptor-molecule which was used as the main acceptor material for bulk heterojunction Organic solar cells.

Key takeaways

Non-fullerene acceptor belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Non-fullerene acceptor to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Non-fullerene acceptor from memory before moving on to harder problems.

Reference excerpt

Non-fullerene acceptors (NFAs) are types of acceptors used in organic solar cells (OSCs). The name Fullerene comes from another type of acceptor-molecule which was used as the main acceptor material for bulk heterojunction Organic solar cells. Non-fullerene acceptors are thus defined as not being a part of this sort of acceptors. Research in non-fullerene acceptors did not show promising results starting up when being compared to fullerene based organic solar cells. However, recent developments in this field launched a series of new opportunities for the NFA based OSCs. The most important breakthrough was the development of the small molecule acceptors (SMAs). These acceptors are showing promising results to be better alternatives for Fullerene acceptors because of their properties. The property that makes these SMAs such a big research topic is their tunability. SMAs can be modified to a much greater extent than Fullerene acceptors. There are, however, still many improvements to make on the design of the SMAs in order become profitable to use in OSCs. Recent research on designing NFA-OSCs showed an efficiency of 15% with a so-called tandem solar cell which made use of Non-fullerene acceptors as well as fullerene acceptors. With a good chance that researchers will be able to boost this percentage up to 18%, it is clear that NFA-OSCs have a great potential in becoming a profitable photovoltaic in commercial application.

NFA Potential

Advantages Fullerene acceptors (FAs) have been used extensively in OSCs. This is rationalized by several characteristics of fullerenes. The three-dimensional character causes them to be suitable materials for bulk heterojunction structures. Additionally, its electronic configuration (delocalized LUMOs) allows for efficient percolation and high electron mobility. Another consequence is that they are easily coupled to compatible donor polymers. However, fullerene acceptor organic solar cells (FA-OSCs) encounter a limited efficiency. The energy levels in fullerene compounds are relatively constant and difficult to alter. Moreover, they employ weak absorption in the visible spectrum and the near-infrared spectrum and low thermal instability and photochemical instability. The acceptors need to be purified extensively, adding to the economical and temporal disadvantages of using FAs. The organic NFAs, in the form of small molecular acceptors (SMAs), can be used to overcome these fullerene deficiencies. They have more structural degrees of freedom, allowing higher electron affinity tunability; they absorb incidental visible-NIR radiation more strongly; they are more stable; they are compatible with donor polymers and they are (in general) easier to synthesize. NF-OSCs with power conversion efficiencies (PCE) of over 13% have been reported, reaching a higher value than its FA-based counterpart.

Disadvantages One of the downsides of using SMAs is the fact that, under atmospheric conditions, they tend to engage in disordered (anisotropic) states as a result of their planar structures. They are often planar as aromaticity is required for sufficient electron mobility. The lack of order may diminish electron transport and effective extraction routes that lead to induced current. Moreover, the corresponding lack of orientation affects donor-acceptor exciton formation. This makes them less compatible for bulk heterojunction blends than FAs. Another downside to research on SMA usage is the profound scala of possibilities of donor-acceptor pairs that scientists are challenged to induce.

Physics

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Non-fullerene acceptor

Start with the simplest possible case. Write down what Non-fullerene acceptor claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Non-fullerene acceptor before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Non-fullerene acceptor ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Non-fullerene acceptor

In research: Non-fullerene acceptor appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Non-fullerene acceptor in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Non-fullerene acceptor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Organic solar cells, so understanding it makes those chapters shorter.
In everyday life: Look for Non-fullerene acceptor outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Non-fullerene acceptor” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Non-fullerene acceptor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Non-fullerene acceptor means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Non-fullerene acceptor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Non-fullerene acceptor in simple terms?

Why does Non-fullerene acceptor matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Non-fullerene acceptor?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Non-fullerene acceptor.