Design And Development Of Organic Semiconductor Photocatalytic Materials Based On Conjugated Molecules

Herein,starting from the two key scientific issues of regulating the band structure of photocatalytic materials and the separation and transport of photogenerated carriers in the photocatalytic process,four innovative studies have been systematically carried out.The three types of novel organic photocatalysts,TCNQ-PTCDI composite photocatalyst（TCNQ-PTCDI）,self-assembled porphyrin（SA-TCPP）,Urea-PDI polymer,have been successfully implemented.The applications of these novel photocatalysts in environmental pollutants treatment,water splitting,decomposition of aquatic oxygen production,tumor treatment and other important fields have been investigated.And the general scientific laws of thermodynamics and kinetics,such as organic molecular dipoles,built-in electric fields,self-assembled structures,have been deeply revealed.A series of TCNQ-PTCDI supramolecular photocatalysts have been successfully constructed,whose visible light photocatalytic performance is more than 10 times higher than that of PTCDI monomers,which can efficiently degrade and treat phenolic pollutants in water.Mechanism studies have confirmed that theπ-πrecombination between TCNQ and PTCDI molecules provides a fast transfer channel for photogenerated carriers,and the strong electron acceptor action of TCNQ further induces the separation of photo-generated carriers.This work provides new ideas for the design and performance regulation of composite organic photocatalysts.A self-assembled supramolecular tetracarboxyphenylporphyrin photocatalyst（SA-TCPP）has been successfully constructed.The SA-TCPP achieves dual functional evolution of hydrogen and oxygen under full spectrum(40.8 and 36.1μmol g^-1 h^-1).And several phonel poluutants can be efficiently degraded with the SA-TCPP,which is more than ten times that of traditional inorganic photocatalysts.Based on the SA-TCPP,the therapeutic effect on solid tumors has been explored and the effect is significant.Mechanism studies have confirmed that the appropriate molecular energy level of TCPP contributes an appropriate band structure for SA-TCPP,ensuring the strong redox capacity;and the large molecular dipole of SA-TCPP have built a strong built-in electric field in photocatalyst promoting the rapid separation and migration of photogenerated carriers.The SA-TCPP can destroy cell structures with photogenerated holes inside cancer cells,and quickly and completely eliminate solid tumors.This work provides new ideas for the design and synthesis of new organic supramolecular photocatalysts and its applications.A highly crystalline urea-perylene imide（Urea-PDI）polymer photocatalyst has been successfully built,which achieves super efficient oxygen evolution production(3223.9μmol g^-1 h^-1)without cocatalysts.Its performance is 106.5 times higher than conventional PDI supramolecular photocatalyst.Mechanism studies have confirmed that the polymer has a deep valence band（+1.52 e V）structure,and thus has the strong oxidation ability.The high crystallinity and large molecular dipoles help Urea-PDI to form a strong built-in electric field,thereby promoting the separation and transmission of photogenerated carriers.In addition,Urea-PDI is very stable,and the performance did not decrease after continuous exposure for 100 hours.This work provides a new material platform for photocatalytic water oxidation and provides ideas for the design and synthesis of new polymer photocatalytic materials.