There is {HEAD ~ a continuing need} for {TAIL ~ photosensitive organic semiconductor compositions} that may be used to produce various optoelectronic devices including photodiodes, photodetectors, and photovoltaic devices  
for
There is { HEAD ~ a continuing need } for { TAIL ~ photosensitive organic semiconductor compositions } that may be used to produce various optoelectronic devices including photodiodes , photodetectors , and photovoltaic devices
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH