Convenient Synthesis and Characterization of Silane-Capped Polysiloles for the Fabrication of Luminescent OLED

Abstract

Catalytic dehydropolymerization and subsequent silane-capping with R2SiHCI (R = Ph, Me) of 1,1-dihydrotetraphenylsilole (1) using various inorganic hydrides produces electroluminescent silane-capped polysiloles (2) in high yield. The polymerization yield and molecular weight increase in the order LiB[CH(CH3)C2H5]3H < NaB[CH(CH3)C2H5]3H < KB[CH(CH3)C2H5]3H. The molecular weights increase in the order Na[H2Al(OCH2CH2OCH3)2] < KB[CH(CH3)C2H5]3H < LiB(C2H5)3H. The silane-capped polysiloles 2 emit at 521 nm and are electroluminescent at 522 nm. The fluorescence quantum yield of 2 in toluene is (1.67 +/- 0.31) x 10(-2). The emission color is green and the maximum brightness of the device is 2900 cd/m2 with a luminous efficiency of 0.69 lm/W. The substituent type of silyl end group showed no appreciable effect on the luminescent properties of polysilole backbone. Thus, the silane-capped polysiloles are found to be a good material for OLED fabrication. A possible mechanism for the formation of 2 was suggested.