具有热退火提升器件V_(OC)特性的Z构型A-DA'D-A结构受体  

Z-configuration A-DA'D-A Type Acceptor with Thermal Annealing Induced High Open Circuit Voltage

作　　者：张丽婷 仇丁丁 张建齐 吕琨 魏志祥[1,2,3,4] ZHANG Liting;QIU Dingding;ZHANG Jianqi;LYU Kun;WEI Zhixiang(CAS Key Laboratory of Nanosystem and Hierarchical Fabrication,Beijing 100190,China;CAS Center for Excellence in Nanoscience,Beijing 100190,China;National Center for Nanoscience and Technology,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing101408,China)

机构地区：[1]中国科学院纳米系统与多级次制造重点实验室,北京100190 [2]中国科学院纳米科学卓越中心,北京100190 [3]国家纳米科学中心,北京100190 [4]中国科学院大学,北京101408

出　　处：《高等学校化学学报》2023年第9期129-142,共14页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51973043);中国科学院战略性先导科技专项(批准号:XDB36000000)资助.

摘　　要：开发具有高开路电压(V_(OC))和有利于减少非辐射重组损失的有机太阳能电池新活性层材料至关重要.本文基于经典吸电子单元(A)-给电子单元(D)结合的A-DA'D-A型受体Y6,开发了一种具有高最低未占分子轨道(LUMO)能级的“Z”构型萘并[1,2-c∶5,6-c']双[1,2,5]噻二唑(NT)核A-DA'D-A受体(ZNT),此分子构型呈现“Z”构型,并通过提高退火温度实现了D18作为给体的器件非辐射复合损失的降低和V_(OC)的提升.为了研究此现象与热退火降低V_(OC)的普遍现象的不同,制备了D18∶Y6体系作为参考.通过提高热退火的温度, D18∶Y6体系的乌尔巴赫能量(EU)升高,非辐射复合损失增大,因此V_(OC)持续降低;与此相反, D18∶ZNT体系的EU随热退火温度升高而降低,非辐射复合损失也有效降低,因此实现了V_(OC)的提高. V_(OC)从未退火条件下的0.950 V提高到80℃退火时的0.963 V, 100℃退火时的0.993 V,直至110℃退火时的0.995 V.退火温度上升时电子迁移率增加,纯ZNT的晶体相干长度增大,证实了能量无序的减少来源于受体ZNT有序性的增加.此外, ZNT受体的(LUMO)、最高占有分子轨道(HOMO)能级和带隙都比Y6的高,结构的平面性更高,器件的激子分离效率较低,使得基于ZNT受体的器件效率低于以Y6为受体的器件.本文报道的“Z”构型A-DA'D-A受体的中热退火使V_(OC)升高的独特现象可为未来高V_(OC)有机太阳能电池的发展提供一个材料设计方向.The development of organic solar cells(OSCs)is approaching the industrial production gradation.In addition to high power conversion efficiency(PCE),it is critical to develop new active layer materials with high open circuit voltage(VOC)and to reduce non-radiative recombination loss.Here,“Z”-configured naphtho[1,2-c∶5,6-c']bis[1,2,5]thiadiazole(NT)nuclear A-DA'D-A receptor(ZNT)with a high lowest unoccupied molecular orbital(LUMO)energy level,is developed based on the electron-withdrawing unit(A)-electron-donating unit(D)combination of A-DA'D-A type acceptor Y6,which emerges a“Z”configuration and achieves a reduction in the non-radiative recombination loss of the device with D18 as the donor by increasing the annealing temperature.In order to investigate the difference between this phenomenon and the general phenomenon of VOC reduction by thermal annealing,the D18∶Y6 system was prepared as a reference.By increasing the temperature of thermal annealing,the Urbach energy(EU)of D18∶Y6 is elevated,and the non-radiative recombination loss is increased,thus,the VOC is consistently reduced.Surprisingly,the increase of the thermal annealing temperature decreases the EU of D18∶ZNT and effectively decreases the non-radiative recombination loss,therefore,the VOC shows an unexpected increase.VOC increases from 0.950 V under the unannealed condition to 0.963 V(80℃),0.993 V(100℃),and even 0.995 V(110℃).Combining the trends of increasing electron mobility with decreasing crystal coherence length(CCL)of the pure acceptor ZNT when the annealing temperature increases,it is inferred that the reduction of energetic disorder is a result of the augmented order of the acceptor ZNT.In addition,the ZNT has a higher LUMO,higher occupied molecular orbital(HOMO)energy levels and band gap than Y6,higher planarity of structure,and lower device exciton dissociation,making the PCE of the ZNT-based devices lower than that of the Y6-based devices.The present work is potentially instructive for the development of A-DA'D-A type

关 键 词：非富勒烯受体 非辐射复合损失 乌尔巴赫能 高开路电压有机太阳能电池 

分 类 号：O626[理学—有机化学] O644.1[理学—化学]