L1, L2 and L each independently represent the single bond, {TAIL ~ a substituted or unsubstituted arylene group} having 6 to 60 nuclear carbon atoms, {HEAD ~ a substituted or unsubstituted heteroarylene group} having 3 to 60 nuclear carbon atoms or a substituted or unsubstituted fluorenylene group 
L1 , L2 and L each independently represent the single bond , { TAIL ~ a substituted or unsubstituted arylene group } having 6 to 60 nuclear carbon atoms , { HEAD ~ a substituted or unsubstituted heteroarylene group } having 3 to 60 nuclear carbon atoms or a substituted or unsubstituted fluorenylene group
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH