Polysilanes are composed of SiSi in main chains.The delocalization of -orbitals along the silicon backbone

results in a HOMO-LUMO band gap as low as 3~4 eV

which leads to a strong absorption in UV region and unique conducting or semiconducting properties with doping.At the same time

linear polysilane also tends to show a good solubility in several solvents.These properties will meet some potential applications as photoconductors

semiconductors

nonlinear optical materials

LEDs and photoresists.However

polysilanes containing SiCl or SiH bonds are moisture and air sensitive

and their optical/conductive properties are unacceptable comparing to other functional polymers.For this reason

the functional modification of polysilane is necessary.In this review

firstly

the relationship between the structure and the electrical characteristics of polysilane is summarized.Conjugate effect

electronic effect and steric hindered effect of substitution provide significant changes in the electronic structure

and then affect the optical and electrical properties of the polysilane.Secondly

the recent progress in polysilane modification methods is classified and reviewed in detail.Post-functionalization is focused on the mild reaction conditions and plenty of selections in functional side groups.Finally

the feasibility in applying polysilanes as base material is prospected.