“…Active metals (Al [ 14 ] and Mg [ 15 ] ), metal compounds (LiF, [ 16 ] Cs 2 CO 3 , [ 17 ] Li 2 CO 3 , [ 18 ] MgO, [ 19 ] ZnO, [ 20 ] TiO 2 , [ 21 ] and MoS 2 [ 22 ] ), and organic polymers (PEO, [ 23 ] PEIE, [ 24 ] and PEI [ 25 ] ) are common EILs in OLEDs. n‐type dopants (e.g., Li, [ 26 ] Cs 2 CO 3 , [ 22 ] Rb 2 CO 3 , [ 3 ] and Li 2 CO 3 [ 27 ] ) incorporating into electron transport material or introducing multilayer‐stacked EILs [ 22,28 ] provides an alternative approach for constructing efficient inverted OLEDs, although such a composite EIL complicates device fabrication process. Lithium carbonate (Li 2 CO 3 ) is an effective electron injection material and n‐type dopant due to its suitable work function, facile solution processability, and easy handling by thermal evaporation.…”