Oxadiazole, Oxazole, and Thiadiazole Polymers

Due to relatively high electron affinity and very good PL efficiency, molecular materials based on oxadiazole, particularly, PBD (21) are among the most popular electron transport materials for OLEDs. The oxadiazole moieties, including PBD, were introduced as pendant 

Inspired by good electron transport properties and high PL of PBD and, particularly, a claim by Heeger and co workers [68] of exceptional performance of PBD MEH-PPV mixtures (EL of up to 50% of the PL yield), Bryce and coworkers [697] reported the first poly(PBD) homopolymer (604) and its aza-derivative (605). The device ITO/PEDOT/MEH-PPV 604/A1 showed cT i of 0.26%, compared to 0.01% obtained with MEH-PPV alone in an identically prepared device. 

Polybenzobisthiazoles 608 and polybenzobisoxazole 609 have been used as efficient electron transport materials in PLEDs [71] (Chart 2.143). Although these polymers show poor fluorescence quantum yields in thin films likely due to excimer formation [700], double-layer devices ITO/PEDOT/polymer/ETL/Al with PPV or MEH-PPV as emissive polymers and 

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