【作者】 周静；

【导师】 陈炜； 刘宗豪；

【作者基本信息】 华中科技大学 ， 光学工程， 2023， 博士

【摘要】 钙钛矿太阳能电池（Perovskite solr cells,PSCs）由于其卓越的性能和巨大的商业价值而得到蓬勃发展,但是目前PSCs的稳定性问题是阻碍其商业化的关键瓶颈之一。这主要是由于钙钛矿（Perovskite,PVSK）在暴露于光、热、水和氧气的环境下会随着时间的推移而发生分解,而且器件结构中的有机功能层以及电极层在外界压力下同样会发生不同程度的降解。针对以上问题,本论文基于本征稳定性良好的反式PSCs器件结构,发展了钙钛矿界面修饰方法、钙钛矿层和电荷传输层交联策略以及多元阻隔策略和封装方法,在兼顾高效率的同时提高电池的稳定性,主要工作包括:（1）发展了一种基于功能性疏水聚合物聚一氯对二甲苯（Parylene C）薄膜的钙钛矿表面修饰方法,用于改善PSCs的稳定性。采用化学气相沉积（Chemical vapor deposition,CVD）技术在钙钛矿表面沉积厚度可控的Parylene C薄膜,使其既能保证电荷的有效隧穿传输,又能保护钙钛矿层免受水汽的侵袭。此外,Parylene C可以通过与未配位Pb²⁺离子相互作用来钝化钙钛矿层的表面缺陷,并在钙钛矿层和PCBM层之间增加电荷回传的势垒,减少界面间电荷复合。结果表明,采用～4 nm Parylene C修饰层的PSCs开路电压和填充因子（Fill factor,FF）显著提高,效率从原始的19.4%提高到21.7%。此外,修饰后的PSCs具有良好的长期热稳定性和工作稳定性,并且稳定性良率也得到了提升。未封装电池在空气中暗态储存、85°C/N₂和恒定光照/N₂条件下老化500 h后,器件效率衰退均控制在11%以内。（2）发展了一种基于聚二甲基硅氧烷（Polydimethylsiloxane,PDMS）作为交联剂的钙钛矿和PCBM双交联策略,以提高PSCs的光热、环境和机械稳定性。未封装的器件在1个太阳光当量光照、60°C和在最大功率点（Maxmium power point,MPP）下连续运行1000 h后,保持其最初效率的97%,在空气中暴露500小时后,保持其初始效率的80%,在弯曲半径为8毫米的曲率半径下弯折循环1000次后,保持其初始效率的85%。与此同时,由于PDMS与钙钛矿组分之间的氢键和Lewis酸碱相互作用,减少了钙钛矿薄膜中的FA空位缺陷和未配位的铅离子缺陷,使得交联后的氧化镍基PSCs获得了24.1 m A cm^–2的电流密度,82.8%的FF和21.6%的效率。（3）发展了基于非贵金属/金属氧化物/聚合物（化学惰性铋电极/Al₂O₃/聚二甲苯薄膜）多元关键阻隔薄膜策略,抑制钙钛矿卤化物组分的消耗和气态钙钛矿分解产物的释放,并且多层屏障形成的紧密封闭系统,可以抑制钙钛矿的降解,使相应的钙钛矿分解反应达到良性平衡。具有多重屏障的FACs基钙钛矿太阳能电池在45℃、1个太阳光当量的白光LED（Light emitting diode）照明下连续工作5200小时后仍维持其初始效率的90%,在75℃、1个太阳光当量的白光LED照明下连续工作1000小时后仍维持其最大功率输出的93%。更多还原

【Abstract】 Perovskite solar cells（PSCs）have experienced substantial growth because of their distinguished property and huge commercial value.Nevertheless,a key bottleneck hindering its commercialization at present is that perovskite（PVSK）degrades over time when exposed to light,heat,water,and oxygen.In addition,the organic functional layer and electrode layer of the component also degrade to different degrees under external pressure sources.In view of the above issues,this thesis investigates the perovskite interface modification,cross-links the perovskite layer and the charge transport layers,and develops stable electrode materials and effective encapsulation methods based on inverted PSCs devices to enhance the stability of PSCs while taking into account the efficiency.The primary task involves:（1）Developing an ultra-thin film of a functional hydrophobic polymer,polychloro-p-dimethyl benzene（Parylene C）,which can largely improve the operational lifetime of PSCs as a surface finish.Chemical vapor deposition（CVD）is adopted to deposit the Parylene C film with adjustable thicknesses on the perovskite surface,which is thin adequately to afford tunnel contact but is also sufficiently shielding to protect the perovskite layer.Besides,it is demonstrated that the Parylene C film can reduce the perovskite surface defects by interacting with the uncoordinated Pb center and act as an effective hole-hindering barrier in the middle of PVSK and PCBM for decreasing carrier recombination.As a result,the PSC using a～4 nm Parylene C layer exhibits a remarkably improvement in open-circuit voltage and fill factor（FF）,resulting in an efficiency boost from 19.4%to 21.7%.Moreover,the Parylene C-based PSCs have attained long-term thermal and operational stabilities with good reproducibility.Without encapsulation,the degradation was limited to 11%after 500h of aging under ambient atmosphere/dark,85°C/N₂,or constant illumination/N₂ conditions.（2）Developing a dual crosslinking strategy using Polydimethylsiloxane（PDMS）as an additive both in the perovskite layer and PCBM interlayer to enhance the thermal,light,ambient air,and flexural stability of PSCs.The unencapsulated devices maintained 97%of their initial efficiencies after continuous operation under 1 sun equivalent illumination,60°C and maximum power point（MPP）tracking for 1000 hours,80%of their initial efficiencies exposed in ambient air for 500 h,and after being subjected to 1000 cycles at a bending radius of 8 mm,they retained 85%of their initial efficiencies.Besides,an improved efficiency for p-i-n PSCs of 21.6%（stabilized at 21.3%）was achieved by increasing simultaneously the short-circuit current density and FF up to 24.1 m A cm^–2 and 82.8%separately,which is credited to the formation of the hydrogen bond and the Lewis acid-base reciprocity between the PDMS and the perovskite reducing the formamidinium（FA）vacancy defects and uncoordinated Pb defects.（3）Developing a multiple key barrier film strategy based on low-cost metal/metal oxide/polymer（chemically inert bismuth electrode/Al₂O₃/polyxylene film）to supress the consumption of halide components and the release of gaseous perovskite decomposition products,and the tightly closed system formed by the multilayer barrier can inhibit the degradation of the perovskite and bring the corresponding decomposition reactions to a benign balance.The resulting encapsulated FACs-based PSCs with multiple-barrier maintain 90%of their initial efficiencies after continuous operation at 45℃for 5200 hours and 93%of their maximum power output after continuous operation at 75℃for 1000 hours under 1 sun equivalent white-light LED illumination.更多还原