Organic electroluminescent materials and devices

The invention relates to organic electroluminescent materials and devices. A compound of a first ligand of Formula I: is provided. In Formula I, portions A and B are each a monocyclic or polycyclic fused ring system; z1 to Z4 are each C or N; k is a direct bond, O or S; each RA and RB are independently hydrogen or a general substituent; at least one RA or RB is R *, wherein R * has the structure of formula II:-L-GeR1R2R3; l is a direct bond or an organic linking group; and LA is coordinated with the metal M through a dashed line; and the metal M is selected from Ir, Rh, Re, Ru, Os, Pt, Pd, Ag, Au or Cu. 本申请涉及有机电致发光材料和装置。提供一种式I：的第一配体的化合物。在式I中，部分A和B各自为单环或多环稠合环系统；Z1至Z4各自为C或N；K为直接键、O或S；每个RA和RB独立地为氢或一般取代基；至少一个RA或RB为R*，其中R*具有式II：--L-GeR1R2R3结构；L为直接键或有机连接基团；并且LA通过虚线与金属M配位；并且金属M选自Ir、Rh、Re、Ru、Os、Pt、Pd、Ag、Au或Cu。