Theoretical Study On Structure Properties Of TIB And P1TZ-1 In PSCs

In modern society,energy shortage and environmental pollution have become a major threat to human survival.It is urgent to find new clean energy.Solar energy is a real clean energy and has abundant reserves.Organic solar cells are characterized by simple manufacturing process,low cost and long-term sustainability.At present,the photoelectric conversion efficiency of organic polymer solar cells has reached more than 10%,so it is of great significance to study polymer solar cells with higher conversion efficiency.In this paper,the structure and photoelectric properties of TIB and P1TZ-1 molecules and their designed molecules are studied.Firstly,oxygen,nitrogen,phosphorus,silicon and selenium atoms were used to replace four sulfur atoms symmetrically located on both sides of TIB molecule and in the receptor part of P1TZ-1 molecule to form two groups of designed molecules.Secondly,thiophene,trithiophene and tetrathiophene were introduced into the receptor part of P1TZ-1 molecule,and then the receptor part of P1TZ-1 molecule was directly replaced by the receptor part of polymer molecule with higher performance,forming the third group of designed molecules.The structure and photoelectric conversion properties of TIB and P1TZ-1 molecule and their designed molecules were theoretically simulated by DFT and TD-DFT methods.The parameters such as the geometrical structure,fluorescence spectrum,charge transfer and recombination rate were calculated and simulated.The results show that the molecular energy gaps of TIB-P and TIB-Si are smaller than those of TIB,the absorption spectrum is red-shifted and the fluorescence lifetime is longer.Compared with P1TZ-1 molecule,PITZ-a,P1TZ-c,P1TZ-P and P1TZ-Si molecule have larger HOMO level,smaller LUMO level,red shift of absorption spectrum,smaller ionization energy and larger electron affinity potential.It shows that TIB-P,TIB-Si,P1TZ-a,P1TZ-c,P1TZ-P and PITZ-Si molecules can better absorb and utilize sunlight.It shows that proper introduction of polythiophene structure and atomic substitution will have a positive impact on the photoelectric properties of TIB and P1TZ-1 molecules.By comparing the performance parameters of TIB and P1TZ-1 and their designed molecules,it can provide ideas and theoretical basis for synthesizing new polymer molecule in the future experiment.