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Impact of Polymer Molecular Weight on Polymeric Photodiodes



Eliot Gann, Christopher McNeill, Lars Thomsen, Siddhartha Saggar, Kedar D Deshmukh, Monirul Hasan, Atul Shukla, Ebinazar B Namdas, Shih-Chun Lo, Jyoti S. Agawane, Nagaraj Nayak, Anil Kumar


The field of organic photodiodes has witnessed continuous development in the last decade. Although a considerable portion of electron-donating materials are polymers, there has been an existential gap in deciphering the influence of polymer chain length or molecular-weight on photodiode performance. We take up OPDs based on a small molecule non-fullerene acceptor blended with different molecular-weights of defect-free form of a well-known polymer, P3HT. The devices were studied for their performance and morphological characteristics. Disparity of up-to a decade in key photodetector characteristics with molecular weight were observed. Tools of near-edge x-ray absorption fine-structure spectroscopy, resonant soft x-ray scattering (R-SoXS) spectroscopy & time delayed collection field measurement were employed to decipher the operating mechanism and fundamental photo-physical processes of the OPDs. We conclude that molecular weight and the morphology of active layer strongly influence photodiode behaviour in particular dark current, linear dynamic range and detectivity.
Advanced Optical Materials


Organic photodiode, Morphology, Photodetector, Organic semiconductor, Conjugated polymer.


Gann, E. , McNeill, C. , Thomsen, L. , Saggar, S. , Deshmukh, K. , Hasan, M. , Shukla, A. , Namdas, E. , Lo, S. , Agawane, J. , Nayak, N. and Kumar, A. (2021), Impact of Polymer Molecular Weight on Polymeric Photodiodes, Advanced Optical Materials, [online], (Accessed June 22, 2024)


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Created November 29, 2021, Updated October 14, 2022