Polymer semiconductors are promising materials for stretchable, wearable, and implantable devices due to their intrinsic flexibility, facile functionalization, and solution processability at low temperatures. However, the crystalline domain of the conjugated structure for high charge carrier mobility in semiconducting polymers exhibits lower stretchability than that of the semi‐crystalline or amorphous domains. Herein, a set of thermoplastic soft semiconductors is synthesized with different ratios of diketopyrrolopyrrole–carbazole–diketopyrrolopyrrole (DPP‐Cz‐DPP)‐based hard segments and thiophene‐based aliphatic soft segments, having the similar structure of thermoplastic elastomers. The polymers exhibit decreased glassy temperatures with the increased content of the soft segments. The polymers show high crystallinity after copolymerization with a large‐sized DPP‐Cz‐DPP core and non‐conjugated segments due to an aggregation property of the conjugated core, still possessing a semi‐crystalline domain after annealing. The polymer films exhibit stretchability under strains of up to 60%. Organic field‐effect transistors fabricated using stretchable polymers show a mobility range of 0.125–0.005 cm2 V−1 s−1 with different proportions of the soft segment. The stretchability is improved significantly and the mobilities are decreased less when the content of the soft segment is increased. Therefore, this study presents a design principle for the development of a high‐performance stretchable semiconducting polymer.
Metal halide perovskite optoelectronic devices have made significant progress over the past few years, but precise control of charge carrier density through doping is essential for optimizing these devices. In this study, the potential of using an organic salt, N,N‐dimethylanilinium tetrakis(pentafluorophenyl)borate, as a dopant for Sn‐based perovskite devices, is explored. Under optimized conditions, the thin film transistors based on the doped 2D/3D perovskite PEAFASnI3 demonstrate remarkable improvement in hole mobility, reaching 7.45 cm2V−1s−1 with a low subthreshold swing and the smallest sweep hysteresis (ΔVhysteresis = 2.27 V) and exceptional bias stability with the lowest contact resistance (2.2 kΩ cm). The bulky chemical structure of the dopant prevents it from penetrating the perovskite lattice and also surface passivation against Sn oxidation due to its hydrophobic nature surface. This improvement is attributed to the bifunctional effect of the dopant, which simultaneously passivates defects and improves crystal orientation. These findings provide new insights into potential molecular dopants that can be used in metal halide perovskite devices.
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