Panchromatic Sequentially Cast Ternary Polymer Solar Cells

In this report, a high-performance all-polymer organic photodetector that is sensitive to linearly polarized light throughout the visible spectrum is demonstrated. The active layer is a bulk heterojunction composed of an electron donor polymer PBnDT-FTAZ and acceptor polymer P(NDI2OD-T2) that have complementary spectral absorption resulting in efficient detection from 350 to 800 nm. The blend film exhibits good ductility with the ability to accommodate large strains of over 60% without fracture. This allows the film to undergo large uniaxial strain resulting in in-plane alignment of both polymers making the film optically anisotropic and intrinsically polarization sensitive. The films are characterized by UV–vis spectroscopy and grazing incidence wide-angle X-ray scattering showing that both polymers have similar in-plane backbone alignment and maintain packing order after being strained. The films are integrated into devices and characterized under linear polarized light. The strain-oriented detectors have maximum photocurrent anisotropies of 1.4 under transverse polarized light while maintaining peak responsivities of 0.21 A W −1 and a 3 dB cutoff frequency of ≈1 kHz. The demonstrated performance is comparable to the current state of the art all-polymer photodetectors with the added capability of polarization sensitivity enabling new application opportunities.