Design,synthesis And Photothermal Properties Of Air-stabilized Perylene Diimide Radicalanions

Photothermal conversion has received more and more attention and research because of its advantages such as low cost,environmental friendliness and high light absorption rate compared with heat energy generation through electrical and chemical energy,etc.Under light radiation,perylene diimide radical anion(PDI^?-)can convert light energy to heat quickly and efficiently by non-radiative relaxation,and is regarded as a potential material for photothermal conversion due to its strong absorption in the near-infrared light region.However,due to the disadvantages of air oxidation and easy aggregation,the preparation of air-stable materials for efficient photothermal conversion has become a major challenge.In this paper,three organic photothermal materials with different photothermal properties for different applications were obtained by stabilizing the perylene diimine radical anion through hydrogen bonding between the H atom on the alkyl primary amine and the O atom on the perylene diimine radical anion.The hydrogen bonding complex formed by the perylenimide radical anion with n-butylamine(n-BL...PDI^?-),the DMF solution with a concentration of 8×10^-3M can achieve a photothermal conversion temperature of 43.4℃,a photothermal conversion efficiency of 23.79%,and a maximum photothermal conversion temperature of 61.1℃under 808 nm laser irradiation;the photothermal conversion temperature of the aqueous solution with a concentration of 2.67×10^-4M is 7.9℃,a photothermal conversion efficiency of 11.02%,and a maximum photothermal conversion temperature was 25.3℃.The liquid photothermal agent prepared from perylene diimide radical anion and branched polyethyleneimine(b-PEI...PDI^?-)not only has good water solubility,but also effectively inhibits the aggregation of PDI^?-in water due to the large spatial site resistance of b-PEI,achieving a photothermal conversion temperature of up to 32.1℃,a photothermal conversion efficiency of 30.48%,and a maximum photothermal conversion temperature of up to 51.1℃,compared with that of n-BL...PDI^?-,the photothermal performance of the aqueous solution of PDI^?-has been significantly improved.In order to meet the demand for solid photothermal materials with high photothermal conversion temperature in the energy field,α-phenylethylamine（α-PEA）with a rigid structure was combined with a perylene diimide radical anion to form a high-temperature stable hydrogen bonding complex(α-PEA...PDI^?-),which is then compounded with graphene oxide with good thermal conductivity to obtain a composite film(α-PEA...PDI^?-/GO)can achieve a maximum photothermal conversion temperature of up to 82.4℃under the irradiation of sunlight simulated by a xenon lamp,and also has a certain solar water evaporation capability with a water evaporation rate of 0.551 kg·m^-2·h^-1under one sunlight irradiation,which is 9.3 times and 1.7 times of the water vapor generation rate of pure water and GO film,respectively.