Engineering Of Hole Transport Material And Components Of Hole Transport Layer For Efficient Perovskite Solar Cell

Recently,organic-inorganic lead halide perovskite solar cell(PSC)receives increasingly attention as a cutting-edge photovoltaic technology owing to its low production cost,straightforward fabrication and high power conversion efficiency(PCE).As an indispensable part of high-efficiency PSCs,the hole transport layer(HTL)plays an important role in improving the photoelectric conversion efficiency and increasing the stability of the device.Spiro-OMe TAD has become the most potential material and is widely used in this area.However,the complicated synthesis and purification procedures lead the price extremely high,limiting their commercial viability.Furthermore,the dopants also increases the production cost of the device.Therefore,the development of low-cost hole transport material(HTM)with excellent photoelectric properties and HTL component engineering have become the research focus.In this thesis,a series of efficient HTMs and bifunctional p-type dopants were constructed by adjusting the core groups and side chains of small organic molecules.The law of change of photoelectric properties of the core group and side chain with the spatial configuration were explored throgut a series of testing and analysis.At the same time,the feasibility of material design were fully verified by introduce in PSCs.The thesis research mainly includes the following aspects:Conventionally,the hydroscopic nature of Li-TFSI and low boiling point of t-BP are considered as the primary limitations of HTL,ultimately affecting the PCE and long-term stability of PSC.To better stress these problems,a dual functional dopant termed PFPPY is reported.The in-depth operating mechanism of PFPPY with SpiroOMe TAD,its profound effects on overall photovoltaic performance and device physics are systematically investigated.It is observed PFPPY can simultaneously take place of t-BP and FK209 in conventional HTL.By employing PFPPY as dopant cooperating with Spiro-OMe TAD,a higher PCE of 21.38% is achieved,compared with the reference device based on t-BP and FK209-doped Spiro-OMe TAD(19.69%).More importantly,the unencapsulated PFPPY-doped device shows greatly improved stability,maintaining over 90% of its initial PCE after 600 h in 40–50% RH.These findings provide a new strategy to optimize the HTL composition for efficient and stable PSCs.Two novel HTMs with indaceno[1,2-b:5,6-b']dithiophene(IDT)as core building block,termed IDT1 and IDT2,were designed and synthesized.The side alkyl chains were introduced to regulate and control the morphology and stacking behavior of HTMs,and the peripheral triarylamine arms were introduced to adjust the energy levels and to facilitate efficient hole transport.Applied in mesoporous structured PSC,HTM IDT1 achieved higher power conversion efficiency(PCE,19.55%)and better stability than Spiro-OMe TAD(19.25%)and IDT2(15.77%)based PSC.These results suggesting the potential of IDT1 as promising HTM for PSCs.Larger ? conjugated system can provide high charge-carrier mobility in HTM of PSC.In the meantime,the optimization of steric configuration was equally important of highly performance HTMs.To better understand this phenomenon,one novel HTM was designed and synthesized based on spiro[fluorene-9,9 '-xanthene](SFX),and the extended 4,4'-Dimethoxydiphenylamine were introduced to adjust the energy levels and larger ?-? conjugation.Based on these optimizations,the SFX-DM-DPA based devices reached an impressive efficiency of 21.6%.These results confirmed the importance of precise structural control for developing efficiently HTMs.