Portal de Periódicos da CAPES

Ultrasensitive organic phototransistors with multispectral response based on thin-film/single-crystal bilayer structures

2015; American Institute of Physics; Volume: 107; Issue: 22 Linguagem: Inglês

10.1063/1.4937005

1520-8842

Rui M. Pinto, Wilson Gouveia, Ana I. S. Neves, H. Alves,

Conducting polymers and applications

We report on highly efficient organic phototransistors (OPTs) based on thin-film/single-crystal planar bilayer junctions between 5,6,11,12-tetraphenyltetracene (rubrene) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM). The OPTs show good field-effect characteristics in the dark, with high hole-mobility (4–5 cm2 V−1 s−1), low-contact resistance (20 kΩ cm), and low-operating voltage (≤5 V). Excellent sensing capabilities allow for light detection in the 400–750 nm range, with photocurrent/dark current ratio as high as 4 × 104, responsivity on the order of 20 AW−1 at 27 μW cm−2, and an external quantum efficiency of 52 000%. Photocurrent generation is attributed to enhanced electron and hole transfer at the interface between rubrene and PC61BM, and fast response times are observed as a consequence of the high-mobility of the interfaces. The optoelectronic properties exhibited in these OPTs outperform those typically provided by a-Si based devices, enabling future applications where multifunctionality in a single-device is sought.