A hyperbranched polymer with enhanced photorefractive effect at low and zero applied electric field

Organic photorefractive (PR) materials are widely applied in electro-optical technologies. However, most PR materials require a high external electric field to show PR effect, which would cause materials dielectric fatigue and electrical breakdown. It is significant to explore materials that demonstrate high PR effects under low and even zero applied electric field. In this work, through Suzuki polymerization, a hyperbranched conjugated polymeric PR materials is prepared to show high PR effects with coupling gain coefficients (Г values) of 86.3 cm⁻¹ and 62.5 cm⁻¹ at low applied electric field of 2.5 V μm⁻¹ and even 0 V μm⁻¹, respectively, which are superior to the performance of its linear analogue. These results verify the advantages of branched structure in producing high PR effect, providing a new approach for PR material design.