Pentacene-based near-infrared organic phototransistor with enhanced responsivity by using ClAlPc/C70 light-absorbing-layer

In this paper, we proposed a high responsive organic pentacene-based phototransistor (OPT) with ClAlPc/C₇₀ heterojunction absorbing-layer designed for near-infrared (NIR) light sensing at the wavelength of 780 nm. ClAlPc exhibits strong optical absorption in the near-infrared region. Fullerene (C₇₀) is commonly used as acceptor materials combinate with the ClAlPc as donor materials to form heterojunction structure to enhance the exciton dissociation and achieve high performance OPTs. The energy level alignment between pentacene/ClAlPc/C₇₀ generates an internal electric field to cause the increased efficiency of the exciton dissociation and the efficient charge transport to the active layer, leading to high photocurrent. The proposed device has high responsivity of 3.36 AW^-1 and achieves a high EQE of 534 % at the wavelength of 780 nm. This work proposes a high-performance OPT with excellent near-infrared light responsivity and exciton dissociation as a result of the designed ClAlPc/C₇₀ absorbing layer with the optimal thickness. It believes that the pentacene-based OPT with the ClAlPc/C₇₀ heterojunction light-absorbing layer will be a good candidate for the development of high-performance NIR-optoelectronic devices.