Research On Interface Problems And Performance Optimization Of Photovoltaic And Memristive Devices Based On Y6 Organic Non-fullerene Acceptor

Organic optoelectronic devices including organic solar cells（OSCs）and organic memory devices,one of the key research directions in the 14th Five-Year Plan,are gaining increasing importance in renewable energy and artificial intelligence application.In recent years,non-fullerene acceptor materials have shown great advantages in spectral absorption,energy level tuning,and photochemical stability due to their large structural differences and adjustable band gap,which have greatly promoted the development of organic semiconductor devices.This thesis takes non-fullerene organic solar cells and organic memristor devices as the research objects,and has conducted a series of comprehensive researches on the common"organic/metal"and"organic/organic"interfaces in organic photovoltaic devices and organic memristors.Main research results are presented as follows:（1）Mo Se₂ QDs with good dispersion were prepared by Lithium-ion intercalation method and Mo Se₂ QDs/poly（3,4-ethylenedioxythiophene）:poly（styrene sulfonic acid）（PEDOT:PSS）bilayer HEL was constructed in OSC.It is found that introduction of Mo Se₂ QDs can alter the work function and phase separation of PEDOT:PSS,thus affecting the morphology of active layer and improving the performance of OSCs.The maximum PCE of OSC based on PM6:Y6and SZ2:N3 bulk heterojunctions were 16.08 and 17.08%respectively,which are among the highest reported value to date for OSCs using 2D materials as the interface modifier.In addition,the introduction of Mo Se₂ QDs effectively prevents the corrosion of the ITO electrode and active layer by PEDOT:PSS,resulting in a significant improvement of the device stability.（2）Mo Se₂ QDs were used as hole transport layer（HTL）to replace poly（3,4-ethylenedioxythiophene）:poly（styrene sulfonic acid）（PEDOT:PSS）commonly used in OSCs.It is found that the power conversion efficiency（PCE）of the device after ultraviolet-ozone（UVO）treatment is 15.31%,which is comparable to the reference device based on PEDOT:PSS.Meanwhile,Mo Se₂ QDs film contributes to tighterπ-πstacking between active layer molecules and higher film crystallinity.In addition,Mo Se₂ QDs as HEL can effectively block the interfacial reaction between Y6 and the conventional extracted layer PEDOT:PSS,significantly improving the stability of the device.（3）Taking advantage of the special advantages of bulk heterojunction,combined with the experience of interface research in non-fullerene OSCs,a bulk heterojunction memristor of PM6:Y6 non-fullerene system was constructed for the first time.By adjusting the thickness of the active layer,the digital and analog memristors are realized respectively.For digital memristors,we further explored the effect of Mo Se₂ QDs interfacial layer on the resistive switching performance of memristors,and successfully realized the logic operation and information display function of the device.For the analog-type memristor,the synaptic function and near-infrared（NIR）light-controlled memristive behavior were successfully realized by changing the pulse parameters（pulse amplitude,pulse width,and pulse interval）and the conductance behavior of the device with（NIR）light intensity in detail.（4）Organic memristor based on PVK:Y6 non-fullerene system was constructed,and the interface morphology of the active layer was optimized by adjusting the ratio of PVK to Y6,and the digital and analog memristors were realized respectively.For analog-type memristors,the conductance behavior of the device is regulated by detailed changes in the pulse parameters（pulse amplitude,pulse width,and pulse interval）,thereby achieving synaptic short-term plasticity.The light-induced learning function was initially realized through light pulse stimulation,and some biological synaptic behaviors were successfully simulated.