Perplexity AI is a conversational search engine marketed as an “answer engine” that answers queries using natural language predictive text. Sources and citations are provided for search answers.
The !band should be: !pplx
The link is: https://www.perplexity.ai/search?s=o&q={{{s}}}
{{{s}}} being the search term.
I also submitted this to DuckDuckGo on their official form.
@TaxingAuthority any reason why you’re not adding it? We can add custom searches and bangs for them. For example:
This is all done via brave://settings/searchEngines where you can Add to Site Search.
@Saoiray Thanks for the reply. I have set up that or similar features in the browsers I use, but it’s only a workaround. Is there a reason it can’t be added as a !bang for Brave Search?
My typical search habit is to search Brave first, then !bang to DDG or Start Page if I’m still finding I need different results. Lately, I’m searching Brave first then needing to copy and paste my search to Perplexity instead of just being able to add the !bang. Yes, there’s a workaround, but having the formal !bang provides ease of use.
Keep in mind I don’t work for Brave and my information is limited, but I’ll try to answer based on my assumptions and understanding.
When you go to places like Brave Search, you’re actually using their database. These companies need to be able to fund their products and don’t want to have excessive demand on their servers. So Brave would require any search engines pulling data to pay them. The reverse is true as well. If Brave were to aggregate results from Perplexity AI, then Brave would be required to pay for the API.
It’s due to this reason that you see browsers have the bangs work as shortcuts for what you type in your address bar and instead navigates directly to that website/database.
Btw, just wanted to add, I never knew about https://search.brave.com/bangs which has a large listing. So on that, I get what you mean about how it doesn’t have Perplexity on it. But when I went to test, it did do exactly what I mentioned where it will always redirect to the websites and won’t just show results. This means it would be the same as creating the site search earlier.
But if you are fine with that and just wanted Perplexity added to the list at https://search.brave.com/bangs then you might just need to submit feedback on https://search.brave.com/ by clicking the gear (settings) 
button that appears while on Brave Search and then clicking on Share Feedback that appears in the menu.
@Dezz it’s because they put in the wrong link. Take a look at my screenshot that was shared.
https://www.perplexity.ai/?q=%s
I would like to second this, I use perplexity and would really like to see it added as a built-in !bang to brave search.
The obvious one would be !perplexity but since that is long and tedious to type, a 3-letter like: !ppx, !plx, !prp or !ppy would be good.
As of the time of writing this post, none of those^ are already used for anything else.