Research Materials And Polymer Aggregation Structure Near-infrared Light Detection

A series of D-A type low band-gap polymers P1, P2and de-tBoc P2, in whichthieno-thiadiazole was used as acceptor and pyrrole as donor, were designed andsynthesized. The polymers were characterized by NMR, elemental analysis, XRDspectroscopy, IR spectroscopy and thermal gravimetric analysis. We studied thephotophysical and electrochemical properties of the polymers. The absorption peaks ofthese polymers films range from865nm to920nm, and the corresponding band gaps ofP1and P2are0.86eV and0.94eV, respectively. The absorption spectra and electronicenergy level can be turned by simply changing the side chains on the donor.The photodetectors based on P1or P2, which mixed with PCBM as the activelayer were fabricated. The relative density of the chromophore was improved afterremoving the side chain on the pyrrole donor by thermal annealing. The deviceperformance significantly improved after introducing2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as the hole blocking layer.