Naphthalimide end-capped diphenylacetylene: a versatile organic semiconductor for blue light emitting diodes and a donor or an acceptor for solar cells

A novel compound 6,6-(ethyne-1,2-diylbis(4,1-phenylene))bis(2-(2-butyloctyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione) (NAI-PVP-NAI) based on an end capping group 1,8-naphthalimide and central building block diphenylacetylene was designed and synthesized by Suzuki coupling. The newly synthesized NAI-PVP-NAI compound is characterized using optical, thermal, and electrochemical techniques as well as ab initio modeling. This novel and unique compound exhibits strong blue emission in the solid state and has been successfully used as an active light-emitting layer in organic light emitting diodes (OLEDs). Interestingly, the newly developed compound shows both electron-donating and electron-accepting abilities. Therefore, it can act as a donor or an acceptor organic semiconductor. Indeed, upon evaluating this molecule in solution processable organic photovoltaic (OPV) devices, we show that it acts as a donor when used with a PCBM acceptor and as an acceptor when used with a P3HT donor. Thus, NAI-PVP-NAI is a versatile compound, which can play three roles as a blue light emitting layer in OLEDs and a donor or an acceptor in OPV devices.