No, you can not. The RFC 5892 standard, as approved by ICANN, states that emojis are prohibited in domain names. We adhere to this standard and thus prohibit the use of emojis in domain names. There are simply many risks in using visual representation in domain names. ICANN has an easy-to-read infographic with the (hidden) risks, see here.
But, we do not limit the use of emojis in subdomains. Therefore, if the applicable software applications allow it, you are free to create a subdomain with one or more emojis. However, be aware of the risks and restrictions that may occur.
Note: there are only 11 top-level domains which allow emoji registration and 14 second-level domain registries. These include .cf, .fm, .ga, .gq, .kz, .ml, .st, .tk, .to, .uz, .ws, .radio.am, .radio.fm, .co.il, .org.il, .com.kz, .biz.ua, .co.ua, .pp.ua, .co.uz, .com.uz, .com.ws, .net.ws and .org.ws. We cannot and will not transfer or register domain names from these registries if the domain name contains an emoji. Our apologies.