Plant-leaf-inspired MXene-silk composite for intelligent solar steam generation combined with mechanical actuation

Solar steam generators based on photothermal materials are important in producing fresh water.However,conventional solar steam generators are difficult to self-adapt to the complex external environment as organisms.Herein,inspired by the plant leaf,we propose a photothermal composite based on MXene and silk to add more functionality.On one hand,the composite achieves an evaporation rate of 1.51 kg·m^(−2)·h^(−1)and a conversion efficiency of 86.9%under a solar intensity of 1 kW·m^(−2),mimicking the water transpiration of plant leaf.On the other hand,the MXene-silk-based actuator shows a maximum bending curvature of 0.91 cm^(−1)under a solar intensity of 5 kW·m^(−2).Furthermore,an intelligent solar system is constructed utilizing the synergy of solar steam generator and actuator,which advances the research from the material level to the system level.Mimicking the behavior of plant leaf,the system can automatically open during the day to generate steam and fresh water.And at night or in bad weather,it will automatically close to prevent external pollution such as dust,achieving intelligent anti-fouling.This research will have good application prospects in less developed areas.Meanwhile,it also provides a certain reference value for exploring multi-functional photothermal devices in the future.

Oxoammonium enabled secondary doping of hole transporting material PEDOT:PSS for high-performance organic solar cells

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)is one of the most widely used hole transporting materials in organic solar cells(OSCs).Multiple strategies have been adopted to improve the conductivity of PEDOT:PSS,however,effective strategy that can optimize the conductivity,work function,and surface energy simultaneously to reach a better energy alignment and interface contact is rare.Here,we demonstrate that oxoammonium salts(TEMPO^+X^-)with different counterions can act as facile and novel dopants to realize secondary doping of PEDOT:PSS.The effective charge transfer process achieved between TEMPO^+X^-and PEDOT:PSS results in enhanced carrier density and improved conductivity of PEDOT:PSS.Moreover,different counterions of TEMPO^+X^-can tune the work function and surface energy of PEDOT:PSS,enabling improved device performances.The resulting device with PM6:Y6 as the active layer shows a high power conversion efficiency(PCE)over 16%.Moreover,this doping strategy can also be applied to other conjugated polymers such as poly(3-hexylthiophene).This work provides a promising strategy to tune the properties of conjugated polymers through doping,thus effectively boosting the performance of organic solar cells.