Q: Is Apple the first to use this kind of screen?

Actually: AMOLED screens have been used in numerous phones since as early as 2008(by Nokia).  In 2010, the Nexus One(Android), followed by the Samsung Galaxy(Android) started using AMOLED.  It's been used on most higher end phones ever since(excluding iphone).

---

Because Samsung has dominated the AMOLED mobile screen production market, Apple rather focused on higher density displays.  Lately, LG(who dominates the television space for OLEDs), has been venturing into the mobile screen space which hopefully will put pressure on Samsung to lower their prices.

I'm glad Apple is finally making the switch.  While their displays have always been good, the color contrast and black levels of AMOLED are a whole other level.  Ideally, the pressure of Apple and Google combined(and their support of LG) will put pressure on Samsung to lower their screen prices.  Until then, get used to $1000+ iPhones.