Efficient near infrared absorbers made easy: Benzodithiophene-based donors in tailored organic-inorganic hybrid architectures for near infrared photodetectors

Organic π-conjugated materials have revolutionized the landscape of optoelectronics and are now widely used in key technologies such as organic light-emitting diodes (OLEDs), organic photovoltaic cells (OPVs), organic fields transistors (OFETs) and sensors. Today, there is a growing interest in pushing the frontier of organic optoelectronics towards the near infrared (NIR) region, unlocking new applications. In this work, we introduce a novel NIR photoresponsive material active in the 700 - 1500 nm range, based on inorganic-organic heterojunction architecture. This system pairs molybdenum oxide (MoO 3 ) with a newly developed large band-gap donor molecule featuring a benzodithiophene core and triarylamine unit. The ease of synthesis, good thermal stability and optimal film forming properties of the new donor material make this approach extremely appealing. We show the processing of the heterostructure by vacuum-evaporation, realizing an interfacial charge transfer complex with impressive NIR absorption properties, whose main features have been studied by photoemission and optical absorption techniques. We demonstrated that the hybrid material can be effectively employed in NIR photodetectors. • New triphenylamine-based donor molecule containing angular benzodithiophene conjugated units has been synthesized. • The material shows excellent thermal stability and amorphous solid state, making it suitable for thin-film applications. • The material was successfully integrated into a hybrid organic-inorganic thin film heterostructure with molybdenum oxide via vacuum-evaporation. • The hybrid heterostructure demonstrated groundbreaking Near Infrared photoresponse across the 700 – 1500 nm wavelength range as a result of the efficient interfacial charge transfer.