In this work a new solution processable small
organic material, namely 2,20 -bithiophene end-capped dihexyloxy phenylene
pentamer (BHBT2) was synthesized, characterized and applied in the fabrication
of an organic ultraviolet photodetector. The material was synthesized via
Williamson etherification, bromination and Suzuki coupling. FTIR and NMR
spectroscopies were recorded for BHBT2 along with its optical, thermal and
electrochemical properties. Finally, BHBT2 was used as donor material to
produce a solution-processed UV photodetector based on a BHBT2 : PC61BM organic
active layer. Results showed that in forward biasing, the photodetector
exhibited a photovoltaic effect with Jsc ¼ 1.80 mA, Voc ¼ 0.66 V, FF ¼ 0.30 and
PCE ¼ 0.98%, while in reverse biasing, the photodetector exhibited a fast,
reversible and stable response with the highest detectivity of 1.47 109 jones.
The realization of efficient UV detection was attributed to the strong
absorption of BHBT2 and PC61BM in the UV region. Hence, the BHBT2 pentamer
coupled with PC61BM can be considered as a potential material to be applied in
a solution-processed organic UV photodetector.