Nonlinear optical absorption and fluorescence of phosphine-substituted bithiophenes in the violet-blue spectral region

► Phosphine-substituted bithiophenes, Ph2(X)P(C4H2S)2P(X)Ph2 (X=O,1;S,2) were studied. ► Both compounds show strong NLO absorption from 420 to 440 nm in the ps regime. ► TPA coefficient was 2.1 cm/GW for 1 and 4.4 cm/GM for 2 at 420 nm with ps laser. ► A dilute CHCl3 solution of 1 shows strong fluorescence at 390 nm. ► Wide band gap and strong fluorescence make 1 a promising host material for blue OLED.