Synthesis And Properties Of Perovskite Hole Transport Layer Materials Based On Large Π Coplanar Structure

The fast-growing population and the world economy have led to continued growth in energy demand.The overuse of fossil energy will eventually exhaust it,and the use of fossil energy will also cause serious environmental pollution.Looking for new energy alternatives is urgent.Solar energy stands out because of its environmental protection and no regional restrictions.Solar cells are one of the most effective ways to utilize solar energy.Among them,the emergence of perovskite solar cells(PSC)has opened an open door for solving energy problems.It has the advantages of light weight,good plasticity,small pollution and low production cost,which has been widely studied.In this paper,two molecules with a largeΠcoplanar structure are selected as the core,and different end groups are grafted to adjust the absorption spectrum,molecular conformation,and molecular aggregation state of the light-absorbing material.Series of molecules has been used as the hole transport layer(HTM)of the PSC.In the second chapter of this paper,an electron-withdrawing unit(A)with Cyclopentyl anthracene containing a largeΠcoplanar structure as the core is designed and synthesized,and conventional triphenylamine molecules with different end group modifications are used as the electron-donating unit(D).Two small molecules with D-A-D structure(D1 and D2)are used in PSCs devices.The decomposition temperatures of the two small molecules by thermogravimetric analysis were 435°C and 381°C.The absorption bands of the thin films of the two molecules are 949 nm and 945 nm,and the optical band gaps are 1.30 e V and 1.31 e V,respectively.The absorption of the two molecules is due to the red shift in the solution in the thin film state,which is due to the formation of a goodΠ-Πstacking through the conjugatedΠbond with the cyclopentyl anthracene as the main chain in the solid film state,Leading to a beneficial increase in charge transport.The devices are obtained with PCE of 17.04%and 19.39%,respectively.Voc of D1 Voc is 1.119 V,Jsc is 22.25 m A/cm~2,FF is 78.05%;Voc of D2 is 1.081 V,Jsc is 20.53 m A/cm~2,FF is 78.07%.In the third chapter of this paper,the electron-withdrawing unit(A)with bis-thiophene-pyranothiophene containing a largeΠcoplanar structure as the core,and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b’]dithiophene(BDT)as the electron-donating unit(D)synthesized two polymers P1 and P2 with D-A structure.Thermogravimetric analysis showed that the decomposition temperatures of the two polymers were 391℃and 416℃,respectively.Compared with P1,the introduction of fluorine atoms in P2 shows that the introduction of fluorine atoms increases the thermal stability of the molecule.The film absorption sidebands of P1and P2 are 875nm and 897nm,and the optical band gaps are 1.41e V and 1.38e V,respectively.The devices are obtained with PCE of 17.66%and 18.47%,respectively.which Voc of P1 is 1.032 V,Jsc is 22.28 m A/cm~2,FF is 76.74%,Voc of P2 is 1.033 V,and Jsc is 22.99 m A/cm~2,FF is 77.74%.