Interface Modification Of Highly Efficient Non-Fullerene Organic Solar Cells

With the objective of optimizing the carrier transport properties of organic solar cells（OSC）,this thesis studied and optimized the hole and electron transport layers as well as investigated the mechanisms.（1）An effective hole transport layer based on MoS₂ NS and PEDOT derivative（DA-P）was developed by an organic-inorganic hybrid strategy for the first time（hereinafter called DM）.When DM was applied to PM6:Y7 OSC and PM6:L8-BO OSC,the PCE was 15.6%and 17.5%,respectively,which are higher than those of using MoS₂ NS and DA-P.Our investigations reveal that the capacity of hole carriers transport and extraction of DM material is improved,mainly due to improved work function and electrical conductivity,which is caused by the further doping of DA-P by MoS₂ oxidation products generated during liquid-phase ultrasonic exfoliation.The work demonstrates an effective hybridization strategy and reveals the interaction between MoS₂ and PEDOT derivatives.（2）A novel double organic electron transport layer（ETL）of OSC is designed and implemented for the first time by employing"N-N heterojunction"strategy.The novel ETL is composed of an alcohol-soluble N-type narrow band-gap conjugated polymer PNDIT-F3N and an alcohol-soluble N-type wide band-gap conjugated small molecule Phen-NaDPO.When those ETL applied to non-fullerene PM6:Y7 OSC,PNDIT-F3N/Phen-NaDPO-based OSC gain a higher PCE of 17.1%,while the control PNDIT-F3N-based OSC and Phen-NaDPO-based OSC gain the PCE of 16.2%and 11.8%,respectively.The experimental results show that the ETL of N-N heterojunction can effectively improve charge transport,inhibit carrier recombination,and enhance selective charge collection.Moreover,the stability of the new ETL-based OSC was significantly improved,which mainly attribute to the following reasons:1)PNDIT-F3N film regulates the matching degree of surface energy between the Phen-NADPO layer and the active layer;2)the ETL was stabilized by chelation between Phen-NaDPO and Ag electrodes.Our work demonstrates the potential of N-N heterojunction as a non-fullerene OSC electron transport layer to improve device performance.