It's nice that you gave two articles to look into for my information. After reading the article 'Why 20 minutes of sunlight is all you need for good sleep, gut health, and immunity" I could see how you develped your claim. The article mainly talks about the benifts from getting direct sunlight or therefore vitamin D. For example, I read about how it helps with bone health, immune support and gut health. So yes, according to this article sunlight is good for many different things involving the human body. After reading the article through I also saw a section related to sleep and it stated, "Sunlight is also needed so that the body can follow a circadian rhythm.(sleep and awake cycle) So yes, the ideas in the articles do point to the fact that sunlight helps with sleep. But the question is, is just 20 minutes of sunlight all you need for good sleep? The other article you put explains more in depth beniftis to vitamin D as well, including better quality sleep. So althoguh vatiamin D does help with sleep, I don't specfilaly see that just 20 minutes is all you need for good sleep. As well as the idea that there are many parts that go into a good night rest. Therefore I would say this claim is likely misinformation.