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Creators/Authors contains: "Shen, Lening"

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  5. Abstract In the past years, piezo-conductive sensors have drawn great attention in both academic and industrial sectors. The piezo-conductive sensors made by inorganic semiconductors exhibited poor mechanical flexibility, restricting their further practical applications. In this study, we report the piezo-conductive sensors by a semiconducting polymer, poly(3,4-ethylenedioxythiophene) doped with tosylate ions (PEDOT:Tos) thin films. Systemically studies indicate that the piezo-conductive response of the PEDOT:Tos thin films is originated from the deformation of the PEDOT crystal cells and the stretched π–π distances induced by Tos. Moreover, the negative piezo-conductive effect, for the first time, is observed from PEDOT:Tos thin film under the pressure. A working mechanism is further proposed to interpret the transient from a positive to a negative piezo-conductive response within the PEDOT:Tos thin films. Our studies offer a facile route to approach effective piezo-conductive sensors based on conjugated polymers.
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  9. Conjugated molecules have been typically utilized as either hole or electron extraction layers to boost the device performance of perovskite solar cells (PSCs), formed from three-dimensional (3D) perovskites, due to their high charge carrier mobility and electrical conductivity. However, the passivating role of conjugated molecules in creating two-dimensional (2D) perovskites has rarely been reported. In this study, we report novel conjugated aniline 3-phenyl-2-propen-1-amine (PPA) based 2D perovskites and further demonstrate efficient and stable PSCs containing a (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film (where MA is CH 3 NH 3 + ). The (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film possesses superior crystallinity and passivated trap states, resulting in enhanced charge transport and suppressed charge carrier recombination compared to those of a 3D MAPbI 3 thin film. As a result, PSCs containing the (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film exhibit a power conversion efficiency (PCE) of 21.98%, which is approximately a 25% enhancement compared to that of the MAPbI 3 thin film. Moreover, un-encapsulated PSCs containing the (PPA) x (MAPbI 3 ) 1− x /MAPbI 3 bilayer thin film retain 50% of their initialmore »PCE after 1200 hours in an ambient atmosphere (25 °C, and 30 ± 10 humidity), whereas PSCs with the 3D MAPbI 3 thin film show significant degradation after 100 hours and a degradation of more than 50% of their original PCE after 500 hours. These results demonstrate that the incorporation of conjugated molecules as organic spacer cations to create 2D perovskites on top of 3D perovskites is an effective way to approach high-performance PSCs.« less