Synthesis Of Fused Heterocycle-based Hole Transport Materials And Their Application In Perovskite Solar Cells

The hole transport layer in perovskite solar cells（PSCs）is responsible for effectively transporting holes and blocking electrons,which plays a key role in improving the photovoltaic performance of battery devices.The commonly used commercial hole transport material（HTM）is 2,2’,7,7’-tetrakis[N,N-bis（4-methoxyphenyl）amino]-9,9’-Spiro-OMe TAD,but it still has the problems of complicated synthesis steps,high synthesis cost and low hole mobility.In order to solve the above problems,several new D-A type hole transport materials were developed by optimizing the structures of electron donor（D）and electron acceptor（A）.（1）With phenanthrimidazole as the electron acdeptor and triphenylamine or carbazole diphenylamine as the electron donor,two kinds of fused heterocyclic smallmolecules 2TPA-PI and p-CZDPA-PI were synthesized,respectively.Both small molecules with asymmetric structure showed good thermal stability.The former has the more planar molecular structure,promoteed the intermolecularπ-πinteraction.As a result,a high hole mobility of 2.31×10^-4 cm² V^-1 s^-1 was achieved by 2TPA-PI.CV test results show that 2TPA-PI has a more negative HOMO energy level,which increases the open circuit voltage(V_oc)of the device.The results of AFM and SEM show that2TPA-PI has good film-forming property,and the hole transport layer film with better compactness and smoothness is prepared,and the perovskite crystal with better quality is obtained.Consequently,in the inverted PSCs,2TPA-PI achieved a power conversion efficiency（PCE）of 17.58%,which was higher than that of the commercial HTM PEDOT:PSS（14.11%）under the same condition.Furthermore,the V_oc was as high as1.162 V and a power conversion efficiency as high as 20.32%was obtained in 2TPA-PI-based normal structural PSCs,which was higher than that of Spiro-OMe TAD（20.21%）.（2）Six kinds of D-A polymer hole transport materials were designed and synthesized with dithianoquinoline or dibenzoquinoline as electron acceptor and triarylamine as electron donor,cited as PHC-1,PHC-2,PHC-3,PHC-O1,PHC-O2 and PHC-O3,respectively.At present,the synthesis and characterization of materials have been completed.The material properties and photovoltaic properties of the conrresponding devices need to be further studied.