Design And Synthesis Of Alkylsilyl Functionalized Copolymer Donor And Semiconductor Small Molecules Based On Tetraphenylethylene And Their Applications In Organic/Perovskite Solar Cells

Nowadys,solar cells are attracting more and more attention because they can convert light energy into electricity,thus realizing green and sustainable development.Organic solar cells based on non-fuller acceptors have made rapid developments in recent years.In the rapid development of non-fullerene organic solar cells,except for the the innovation of new non-fullerene acceptors,the design and synthesis of polymer donors also act as a significant role in the development of deviceperformance.Because of the molecular structure,basic photoelectric properties and aggregation characteristics of the non-fullerene acceptors that are commonly used today are quite different with the fullerene acceptors;the non-fullerene acceptors have new requirements for polymer donors.This article is mainly based on the understanding of the relationship between the structure and performance of semiconductor materials in solar cells,the research was carried out to optimism the energy level and structure of polymer donor,improve the morphology of active layer,to obtain efficient organic solar cells and stable perovskite solar cells.A new alkylsilyl functionalized copolymer donor PBDS-T was designed and synthesized for efficient PSCs.Due to the ?*(Si)-?*(C)bond interaction,PBDS-T showed the lower energy levels and higher crystallinity than PBDB-T analogue.Due to the higeh crystallinity of PBDS-T and optimal morphology of PBDS-T:ITIC.A record PCE over 11%with simultaneously improved VOC,JSC and small Eloss was obtained for annealing-free device.We have carefully selected three representative non-fullerene acceptors(ITIC,ITIC-F and ITIC-Thl)as acceptors for alkylsilyl functionalized copolymers PBDS-T donor to reveal the basic principle of how to select donor and acceptor to optimize the morphology of active layer and realize the best device performance.We found that the interactions between donor and acceptor,the crystallinity of each component and difference in the surface tensions impact greatly on the morphology of blend films and their eventually device performance.A solution-processible 3D molecule TPE-DPP4 based on 1,1,2,2-tetrakis(4-bromophenyl)ethene(TPE)as core and diketopyrrolopyrrole(DPP)as arm was synthesized in a facile way.Attractively,just like the PCBM,the TPE-DPP4 appended to CH3NH3PbI3 film can also effectively improve crystallinity of CH3NH3PbI3 by filling pinholes and vacancies between perovskite grains.Besides,the perovskite with TPE-DPP4 have significant stronger absorption compared with the pure perovskite film.Moreover,the TPE-DPP4 can also function as an additional electron donor electron donor to transfer electrons to perovskite,which make the light-absorbing layer to be a perovskite+TPE-DPP4 bulk heterojunction hybrid film.As a result,the perovskite solar cells with TPE-DPP4 obtained an enhanced PCE of 40%enhancement to device with pristine perovskite.Finally,we used molecules with aggregation-induced luminescence(AIE)to improve the efficiency and stability of perovskite solar cells.A molecular TPE-CZ with AIE effect was designed and synthesized by a simple and feasible method as a new hole transport layer(HTL)for perovskite solar cells.More importantly,the overall enhanced performance,including efficiency and stability,of the device is observed to be correlated with the AIE effect of TPE-CZ.Such AIE effect not only can convert the ultraviolet light in the incident light to visible light which reabsorbed by perovskite to improve the photocurrent.