Poly phosphorescence devices

Due to the large band gap and high triplet energy level of the poly(3, 6-dibenzosilole) 5, the copolymer is an excellent host for the fabrication of blue polymer phosphorescent light-emitting diodes. A high external quantum efficiency (t/el) of 4.8% and a luminance efficiency of 7.2 cd/A at 644 cd/m2 have been achieved for blue phosphorescence devices (emission peak (AEL) at 462 nm, CIE coordinates x = 0.15,y = 0.26). The performances of the devices are much better than those reported for blue phosphorescent devices with poly(A--viny 1 cabarzo 1 e) (PVK) as the host.32... 

S Kan, X Liu, F Shen, J Zhang, Y Ma, Y Wang, and J Shen, Improved efficiency of single-layer polymer light-emitting devices with poly(vinylcarbazole) doubly doped with phosphorescent and fluorescent dyes as the emitting layer, Adv. Funct. Mater., 13 603-608, 2003. 

PVK are critical in achieving high efficiency. While conjugated polymers, such as poly(fluorenes) and poly(phenylene-vinylenes), have been used extensively for fluorescence-based devices, they are not as useful for phosphorescence-based devices because they characteristically have low triplet energies. The triplet levels of most conjugated polymers are in the red to near-IR spectral region, and thus efficiently quench phosphorescence from dopants designed to emit in the visible part of the spectrum." ... 

Chan KL, Watkins SE, Mak CSK, McKieman Ml, Towns CR, Pascu SI, Holmes AB (2005) Poly(9,9-diaIkyl-3,6-dibenzosilole) a high energy gap host for phosphorescent light emitting devices. Chem Common 5766-5768... 

---