High response deep ultraviolet organic photodetector with spectrum peak focused on 280 nm

A high response organic deep ultraviolet (DUV) photodetector (PD) with 280 nm as the response spectrum peak was demonstrated. A maximum photoresponse of 309 mA/W under 280 nm UV illumination with an intensity of 0.428 mW/ cm ² and a detectivity of 1× 10¹² cmHz^1/2/W at -8 V were achieved, respectively. The optimized PD diode has a structure of ITO/m-MTDATA (10 nm)/m-MTDATA:Bphen(1:1, 60 nm)/Bphen (10nm)/Cs ₂CO₃: Bphen (30 wt %,10 nm)/Al(12 nm)/TPD(40 nm). Under 280 nm constant and shuttered illumination conditions with an intensity of 0.18 mW/ cm² the operational time is longer than 440 min when its response respectively decreases to 50% and 83% of its original value. The realization of the DUV detection is attributed to the stronger absorption of shorter UV wavelengths of Bphen acceptor and covering UV waveband longer than 300 nm by the TPD layer. The more detailed mechanism of harvesting the high PD performance is also discussed. © 2010 American Institute of Physics.