Patent ID: 8216699

Claim:
An organic light-emitting device comprising a phosphorescent layer disposed between two electrodes, wherein said device has a CIE-y coordinate of less than 0.25, and wherein said phosphorescent layer comprises: (a) a cyclometallated complex comprising the structure of formula I: wherein: M is a d-block transition metal; B is a five- or six-membered aryl or heteroaryl ring which is optionally substituted and optionally fused to one or more other aryl or heteroaryl rings; A is a five- or six-membered heteroaryl ring comprising at least three nitrogen atoms; R 1 is a group other than hydrogen; n is zero or an integer equal to or greater than one; and A and B are optionally fused or linked by one or more covalent bonds; or (b) a cyclometallated complex comprising the structure of formula II: wherein M is a d-block transition metal, A is a five- or six-membered heteroaryl ring which comprises at least three heteroatoms and which is optionally substituted or fused, B is a five- or six-membered aryl or heteroaryl ring which is optionally substituted or fused, n is greater than one and R 1 is a dendron or a solubilising group; or (c) a polymer, which polymer comprises a cyclometallated complex, wherein the cyclometallated complex comprises the structure of formula I or formula II and is incorporated in a main chain or a side chain of the polymer.