Efficient Photoinduced Charge Transfer between Linear Conjugated Polymer and Polymer Network for Light Harvesting Application

Abstract

The development of light-harvesting systems based on a donor–acceptor heterostructure for efficient conversion of light to renewable energy is an emerging area of research. Here, we have demonstrated an efficient donor–acceptor heterostructure by hybridizing a high-band gap conjugated polymer network (CPN) with a linear conjugated polymer P3HT to boost charge separation and the light-harvesting property. Steady-state and time-resolved spectroscopic studies show efficient photoinduced electron transfer from P3HT to CPN and simultaneous hole transfer from CPN to P3HT due to the proper alignment of the band gap. The light-harvesting property of the hybrid materials was demonstrated by employing the hybrids as active layers for the fabrication of all polymer photodiodes which show photodetectivity from ultraviolet A to the entire visible region with high responsivity (0.85 A/W) and detectivity of 2.41 × 10¹¹ Jones at 620 nm and −5 V in a CPN/P3HT blend of 1:1. The repetitive on–off switching of a photodetector at zero bias clearly indicates its ability to operate in self-biased mode. This result will open up more possibilities for designing a light-harvesting system based on a high-band gap conjugated polymer network that can utilize UV and visible regions of solar light.