A new 2

5-dithienylsilole (TST) with triphenylamine substituents at the 3

4-positions was synthesized.The TST was utilized to construct conjugated silole-containing poly(3

6-carbazole)s PCz-TST with TST contents of 1%～20%.The weight-average molecular weights of the PCz-TST were between 9000 and 10600

with polydispersity index between 1.3 and 1.5.Optoelectronic properties of the PCz-TST

such as UV absorption

cyclic voltammetry

photoluminescence (PL) and electroluminescence (EL) were investigated.The main absorption peaks of PCz-TST

which were ascribed to the contribution of the carbazole segments

were at 305 nm

while the absorption of the TST units was around 498 nm.The optical band gaps of the PCz-TST were between 2.06～2.18 eV.PL spectra of the copolymers showed excitation energy transfer from the carbazole segments to the silole units

displaying one orange peak for the film PL spectra.The peak positions of red EL spectra were between 604～645 nm

showing obvious red-shifts relative to the PL spectra.HOMO levels of PCz-TST were between -4.95 eV and -5.09 eV

with more than 1 eV energy barrier for holes to enter TPBI blocking layer.In EL devices with a configuration of ITO/PEDOT/PCz-TST/TPBI/Ba/Al

a maximum external quantum efficiency of 1.94% was achieved for the copolymer with 5% TST.The TPBI hole blocking layer largely improved the efficiency of the exciton formation

from which the highly efficient red EL from the silole units could be displayed.Red shifted EL spectra were found for the introduction of the TPBI layer

from which the color purity of red light was modified.