具有2D-EDAPbI4薄覆盖层的环境稳定的FAPbI3基钙钛矿太阳能电池（英文）

二维(2D)卤化铅钙钛矿材料是钙钛矿太阳能电池(PSC)中最有前途的吸光材料之一,具有优异的稳定性和缺陷钝化作用.然而,这些稳定的二维PSC的转换效率仍远远落后于三维钙钛矿电池.在本文中我们通过原位生长的方法将2D EDAPbI4层成功制备在3D FAPbI3层表面。这种合理设计的2D-3D钙钛矿薄膜分层结构可以明显提高电池的效率.另外,由于EDAPbI4层的高抗湿性和抑制迁移, 2D-3D电池器件显示出明显增强的长期稳定性,在200 h内一直保持初始转换效率,甚至在500 h后仍能保持其初始转化效率的90%.     

弛豫铁电体基陶瓷薄膜的溶胶-凝胶制备和电性能研究

采用溶胶-凝胶工艺成功地制备了纯钙钛矿结构的Pb(Mg1/3Nb2/3)0.65Ti0.35O3(简称PMNT)弛豫型铁电陶瓷薄膜,分析了溶胶先驱体中铅含量对PMNT薄膜钙钛矿结构稳定性的影响规律,表明热退火过程的氧化铅气氛层覆盖技术对获得纯钙钛矿结构PMNT薄膜材料至关重要,系统测试了纯钙钛矿PMNT薄膜材料的铁电和介电性能,提出弛豫型铁电PMNT陶瓷薄膜制备中晶粒自由结晶和异常生长动力学机制.     

无铅锡钙钛矿太阳电池薄膜的制备工艺研究

采用一步溶液法制备了锡钙钛矿电池薄膜,研究了前驱体溶液浓度、退火温度和掺杂对薄膜成膜性能的影响。分别利用扫描电镜(SEM)、XRD和傅里叶红外光谱仪(FTIR)对薄膜的形貌、物相、吸收率和禁带宽度进行表征和测试。研究结果表明,当前驱体溶液浓度为30%、退火温度为100℃时的成膜性能较好,所制备的钙钛矿薄膜更加平整和光滑,覆盖率较高。CH_3NH_3SnI_3成分的钙钛矿薄膜具有最低的禁带宽度,其吸光性能优于其他成分的钙钛矿薄膜。掺杂Br、Cl离子会导致CH_3NH_3SnI_3成分的钙钛矿薄膜的禁带宽度增加,而吸光性能和结晶性能降低。     

下转换发光材料对钙钛矿本征性能的影响研究

利用太阳光的近红外和紫外部分实现全光谱响应无疑已成为提高钙钛矿太阳能电池功率转换效率的重要焦点。通过引入光致发光转换层将近红外或紫外光转换为可见光被钙钛矿光活性层利用,已被认为是一种非常有前景的途径。将两种经典的下转换发光材料(红粉和黄粉)引入钙钛矿本征层,采用一步旋涂法制备钙钛矿薄膜。利用缺陷评定高级显微系统、扫描电镜(SEM)、X射线衍射(XRD)、紫外可见吸收及荧光光谱分别探究了下转换发光材料对钙钛矿薄膜表面粗糙度、形貌、结构及光谱性能的影响。结果表明：下转换发光材料能够优化钙钛矿薄膜表面粗糙度、形貌,并未改变钙钛矿结构。紫外可见分光光度计和荧光光谱仪的结果证实了下转换发光材料确实能够拓宽钙钛矿薄膜的光谱响应范围,使整个吸收光谱范围向短波长方向移动,为有效利用全光谱提供了新思路。     

利用混合溶剂实现钙钛矿材料微观结构和光电性能优化

采用纯N, N-二甲基甲酰胺(DMF)溶剂、纯二甲基亚砜(DMSO)溶剂以及DMSO/DMF不同体积比例混合溶剂制备钙钛矿(CH₃NH₃PbI₃)薄膜, 并系统研究了不同溶剂对钙钛矿薄膜微结构及光电特性的影响。结果表明, 随着DMSO在混合溶剂中比例增加, 钙钛矿薄膜平均晶粒尺寸增大, 碘化铅(PbI₂)残留量降低, 同时薄膜中有序的钙钛矿晶体所占比例呈现先增大后减小的趋势, 并且当DMSO占混合溶剂体积比为60%时达到最大。薄膜Urbach能, 载流子寿命以及PbI₂含量之间的关系表明, 微量的PbI₂可有效钝化钙钛矿薄膜的缺陷。经过优化后(DMSO占混合溶剂体积比为30%), 钙钛矿太阳电池的光电转换效率达到15.1 % (V_OC=0.99 V; J_SC=20.9 mA/cm²; FF=0.73)。     

空间限域生长CsBi3I10无铅钙钛矿用于高质量、高灵敏度和高稳定性近红外光电探测器

因具有较高的耐热性和较长的电子扩散长度,无铅钙钛矿Cs Bi3I10备受关注.然而,由于二维结构Cs Bi3I(10)钙钛矿的表面极其粗糙且存在大量针孔,导致Cs Bi3I10钙钛矿器件性能不高.本文报道了一种利用空间限域生长(SCG)获得高平滑度、高结晶度和致密CsBi3I10钙钛矿薄膜的方法.相对于传统旋涂法制备的...     

单源热蒸发制备有机无机杂化CH3NH3PbI3薄膜及其性能表征

采用全真空单源热蒸发沉积技术直接制备钙钛矿太阳电池用有机无机杂化CH₃NH₃PbI₃薄膜。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能量色散谱仪(EDS)和分光光度计对制备的CH₃NH₃PbI₃薄膜微结构、表面形貌、化学成分和光学性能进行表征分析, 并与非真空旋涂法制备的CH₃NH₃PbI₃薄膜性能进行比较。结果表明: 单源热蒸发法制备的CH₃NH₃PbI₃薄膜呈现单一的钙钛矿四方晶体结构, 且与蒸发源材料的晶体结构同源性高, 没有出现杂质相偏析; 对比旋涂法制备的CH₃NH₃PbI₃薄膜表面均匀致密平整, 且薄膜结晶度更高; 单源热蒸发法制备的CH₃NH₃PbI₃薄膜禁带宽度为1.57 eV, 符合钙钛矿太阳电池吸收层光学性能要求。     

有机/无机层状类钙钛矿(C12 H25 NH3)2 PbI4晶体及薄膜的制备与结构表征

介绍了有机/无机类钙钛矿(C12H25NH3)2PbI4的晶体和薄膜的制备,并采用了XRD、SEM、AFM和PL表征材料的结构、形貌及光学特性等.XRD实验表明制备的(C12 H25NH3)2PbI4晶体结晶度高.探索旋涂法制备工艺参数对薄膜结构的影响,在薄膜XRD中几乎只能观察到(0021)晶面的衍射峰,表明有机/无机类钙钛矿层沿平行与基片方向择优生长,SEM和AFM表明薄膜致密性较好,表面粗糙度较小.     

基于印刷技术制备钙钛矿太阳电池

近年来,钙钛矿太阳电池(Perovskite solar cells,PSCs)以其优异的光电转换性能和溶液制备成本低等优势受到了科研工作者和产业界人士的广泛关注,被认为是新一代薄膜太阳电池技术中的杰出代表。目前,钙钛矿太阳电池的光电转换效率(Power conversion efficiency,PCE)已经从2009年报道的3.8%迅速提升到现在的22.7%,达到商业化多晶硅、碲化镉、铜铟镓硒等太阳电池水平。目前,溶液旋涂法是实验室制备钙钛矿太阳电池的常用方法。虽然旋涂法操作简单、成膜速度快、重复性好,然而该法缺点也很明显:(1)材料浪费严重;(2)不具备图案化功能;(3)不适用于工业化的连续生产。因此,溶液旋涂技术无法满足钙钛矿太阳电池今后大规模工业化生产所需的大面积、低成本等制造要求。从实验室小面积器件制备转变到可大面积的产业化制备以及降低钙钛矿太阳电池的生产成本,将是钙钛矿太阳电池产业化过程中的一个重要课题。在钙钛矿太阳电池的制备方法中,印刷技术因具有材料利用率高、成本低、工艺效率高、可大面积制备、适用于柔性基底等特点而备受关注。基于印刷工艺制备的小面积钙钛矿太阳电池效率已接近20%,大面积(10cm2)钙钛矿太阳电池效率在10%～16%之间,大面积柔性钙钛矿太阳电池效率为10%左右。然而,从实验室小器件转变到大规模工业化生产依旧存在许多问题亟待解决。例如:(1)为了加快钙钛矿材料的结晶,在钙钛矿薄膜退火过程中通常采用溶剂工程或惰性气体辅助的方式,这将导致印刷的大面积钙钛矿薄膜质量难以控制以及重复性降低;(2)退火过程中较高的退火温度会限制柔性基底和界面材料的选择;(3)钙钛矿材料本身对空气湿度敏感,需提高钙钛矿层制备过程的环境适应性,降低制备工艺本身对环境条件的限制等。基于此,完善钙钛矿太阳电池的印刷制备工艺并使其适用于工业化生产显得十分重要。本文综述了基于喷墨打印(Inkjet-printing)、喷涂(Spray-coating)、狭缝涂布(Slot-die coating)、刮涂(Doctor-blading)等印刷技术制备钙钛矿太阳电池的研究进展,并对印刷技术制备钙钛矿太阳电池的前景进行了展望。     

钙钛矿太阳能电池界面工程优化研究

有机-无机杂化钙钛矿太阳能电池(PSCs)具有高能量转换效率、低能耗和低成本等优点,但PSCs界面缺陷引起的非辐射复合严重阻碍了其光电转换性能提升。本研究通过降低氧化镍空穴传输层的粒径尺寸,提高粒径均匀性,实现了光生空穴在电池界面的高效传输;并通过优化钙钛矿薄膜的反溶剂作用时间提升结晶质量,降低界面非辐射复合,改善空穴传输层和钙钛矿的界面问题,使钙钛矿太阳能电池的能量转换效率(PCE)从10.11%提高到18.37%。开尔文探针力显微镜(KPFM)研究表明,界面优化后的钙钛矿薄膜在亮态下的表面接触电位差相比于暗态下增加了120.39 mV。采用压电力原子力显微镜(PFM)分析钙钛矿薄膜明暗态铁电性能,发现界面优化后的钙钛矿铁电极化变化微弱,说明优化界面有效降低了电池界面缺陷和迟滞效应。该研究结果表明,优化氧化镍空穴传输层,提高钙钛矿薄膜质量,减少了界面缺陷,降低了非辐射复合和电池迟滞效应,提高了钙钛矿太阳能电池的能量转换效率。     

Magnetic Field-Assisted Interface Embedding Strategy to Construct 2D/3D Composite Structure for Stable Perovskite Solar Cells with Efficiency Over 24%

Perovskite solar cells (PSCs) based on 2D/3D composite structure have shown enormous potential to combine high efficiency of 3D perovskite with high stability of 2D perovskite. However, there are still substantial non-radiative losses produced from trap states at grain boundaries or on the surface of conventional 2D/3D composite structure perovskite film, which limits device performance and stability. In this work, a multifunctional magnetic field-assisted interfacial embedding strategy is developed to construct 2D/3D composite structure. The composite structure not only improves crystallinity and passivates defects of perovskite layer, but also can efficiently promote vertical hole transport and provide lateral barrier effect. Meanwhile, the composite structure also forms a good surface and internal encapsulation of 3D perovskite to inhibit water diffusion. As a result, the multifunctional effect effectively improves open-circuit voltage and fill factor, reaching maximum values of 1.246 V and 81.36%, respectively, and finally achieves power conversion efficiency (PCE) of 24.21%. The unencapsulated devices also demonstrate highly improved long-term stability and humidity stability. Furthermore, an augmented performance of 21.23% is achieved, which is the highest PCE of flexible device based on 2D/3D composite perovskite films coupled with the best mechanical stability due to the 2D/3D alternating structure.     

Record Efficiency Stable Flexible Perovskite Solar Cell Using Effective Additive Assistant Strategy

Even though the power conversion efficiency (PCE) of rigid perovskite solar cells is increased to 22.7%, the PCE of flexible perovskite solar cells (F‐PSCs) is still lower. Here, a novel dimethyl sulfide (DS) additive is developed to effectively improve the performance of the F‐PSCs. Fourier transform infrared spectroscopy reveals that the DS additive reacts with Pb²⁺ to form a chelated intermediate, which significantly slows down the crystallization rate, leading to large grain size and good crystallinity for the resultant perovskite film. In fact, the trap density of the perovskite film prepared using the DS additive is reduced by an order of magnitude compared to the one without it, demonstrating that the additive effectively retards transformation kinetics during the thin film formation process. As a result, the PCE of the flexible devices increases to 18.40%, with good mechanical tolerance, the highest reported so far for the F‐PSCs. Meanwhile, the environmental stability of the F‐PSCs significantly enhances by 1.72 times compared to the device without the additive, likely due to the large grain size that suppresses perovskite degradation at grain boundaries. The present strategy will help guide development of high efficiency F‐PSCs for practical applications.     

Enhancing Crystallization in Hybrid Perovskite Solar Cells Using Thermally Conductive 2D Boron Nitride Nanosheet Additive

Controlling crystallization and grain growth is crucial for realizing highly efficient hybrid perovskite solar cells (PSCs). In this work, enhanced PSC photovoltaic performance and stability by accelerating perovskite crystallization and grain growth via 2D hexagonal boron nitride (hBN) nanosheet additives incorporated into the active perovskite layer are demonstrated. In situ X-ray scattering and infrared thermal imaging during the perovskite annealing process revealed the highly thermally conductive hBN nanosheets promoted the phase conversion and grain growth in the perovskite layer by facilitating a more rapid and spatially uniform temperature rise within the perovskite film. Complementary structural, physicochemical, and electrical characterizations further showed that the hBN nanosheets formed a physical barrier at the perovskite grain boundaries and the interfaces with charge transport layers, passivating defects, and retarding ion migration. As a result, the power conversion efficiency of the PSC is improved from 17.4% to 19.8%, along with enhanced device stability, retaining ≈90% of the initial efficiency even after 500 h ambient air storage. The results not only highlight 2D hBN as an effective additive for PSCs but also suggest enhanced thermal transport as one of the pathways for improved PSC performance by 2D material additives in general.     

Dimensional Tuning of Perylene Diimide-Based Polymers for Perovskite Solar Cells with Over 24% Efficiency

The hygroscopic dopants used in Spiro-OMeTAD hole transport material (HTM) in state-of-the-art perovskite solar cells (PSCs) inevitably induce premature degradation of the devices. Here, two multifunctional polymer interface materials based on the perylene diimides (PDI) unit are developed. It is found that quasi-two-dimensional (2D) polymer 2DP-PDI can form a denser film and exhibit better hydrophobicity than linear polymer P-PDI. Importantly, 2DP-PDI can passivate the surface defects and extract hole carriers of perovskite film more effectively, leading to much reduced nonradiative recombination loss. With polymer interface material between the perovskite and HTM layers, the optimized device using 2DP-PDI and P-PDI yields a champion PCE of 24.20% and 23.09%, respectively, along with significantly improved stability, whereas the control device shows a lower efficiency of 22.23%. These results suggest that developing multifunctional polymer interface materials can be a promising strategy to improve the efficiency and stability of PSCs.     

Secondary Anti-Solvent Treatment for Efficient 2D Dion–Jacobson Perovskite Solar Cells

Surface defects-mediated nonradiative recombination plays a critical role in the performance and stability of perovskite solar cells (PSCs) and surface post-treatment is widely used for efficient PSCs. However, the commonly used surface passivation strategies are one-off and the passivation defect ability is limited, which can only solve part of the defects in the topmost surface area. Here, a secondary anti-solvent strategy is proposed to further reduce surface defects based on conventional surface passivation for the first time. Based on this, the crystallization quality of 2D Dion–Jacobson perovskite is enhanced and the surface defects density is further reduced by nearly two orders. In addition, a gradient structure of perovskite with n = 2 phases located at the top of the film and 3D-like phases located at the bottom of the film can also be obtained. The modulated perovskite film boosts the efficiency of 2D perovskites (n = 5) up to 19.55%. This strategy is also very useful in other anti-solvent processed perovskite dipping systems, which paves a promising avenue for minimizing surface defects toward highly efficient perovskite devices.     

Extrinsic Ion Distribution Induced Field Effect in CsPbIBr2 Perovskite Solar Cells

Excellent power conversion efficiency (PCE) and stability are the primary forces that propel the all‐inorganic cesium‐based halide perovskite solar cells (PSCs) toward commercialization. However, the intrinsic high density of trap state and internal nonradiative recombination of CsPbIBr₂ perovskite film are the barriers that limit its development. In the present study, a facile additive strategy is introduced to fabricate highly efficient CsPbIBr₂ PSCs by incorporating sulfamic acid sodium salt (SAS) into the perovskite layer. The additive can control the crystallization behaviors and optimize morphology, as well as effectively passivate defects in the bulk perovskite film, thereby resulting in a high‐quality perovskite. In addition, SAS in perovskite has possibly introduced an additional internal electric field effect that favors electron transport and injection due to inhomogeneous ion distribution. A champion PCE of 10.57% (steady‐output efficiency is 9.99%) is achieved under 1 Sun illumination, which surpasses that of the contrast sample by 16.84%. The modified perovskite film also exhibits improved moisture stability. The unencapsulated device maintains over 80% initial PCE after aging for 198 h in air. The results provide a suitable additive for inorganic perovskite and introduce a new conjecture to explain the function of additives in PSCs more rationally.     

Dual function of a high-contrast hydrophobic-hydrophilic coating for enhanced stability of perovskite solar cells in extremely humid environments

In spite of a continuous increase in their power conversion efficiency (PCE) and an economically viable fabrication process,organic-inorganic perovskite solar cells (PSCs) pose a significant problem when used in practical applications:They show fast degradation of the PCE when exposed to very humid environments.In this study,the stability of PSCs under very humid conditions is greatly enhanced by coating the surface of the PSC devices with a multi-layer film consisting of ultrahydrophobic and relatively hydrophilic layers.A hydrophobic composite of poly(methyl methacrylate) (PMMA),polyurethane (PU),and SiO2 nanoparticles successfully retards the water molecules from very humid surroundings.Also,the hydrophilic layer with moderately PMMA captures the residual moisture within the perovskite layer;subsequently,the perovskite layer recovers.This dual function of the coating film keeps the PCE of PSCs at 17.3％ for 180 min when exposed to over 95％ humidity.     

Graded 2D/3D Perovskite Heterostructure for Efficient and Operationally Stable MA-Free Perovskite Solar Cells

Almost all highly efficient perovskite solar cells (PVSCs) with power conversion efficiencies (PCEs) of greater than 22% currently contain the thermally unstable methylammonium (MA) molecule. MA-free perovskites are an intrinsically more stable optoelectronic material for use in solar cells but compromise the performance of PVSCs with relatively large energy loss. Here, the open-circuit voltage (V_oc) deficit is circumvented by the incorporation of β-guanidinopropionic acid (β-GUA) molecules into an MA-free bulk perovskite, which facilitates the formation of quasi-2D structure with face-on orientation. The 2D/3D hybrid perovskites embed at the grain boundaries of the 3D bulk perovskites and are distributed through half the thickness of the film, which effectively passivates defects and minimizes energy loss of the PVSCs through reduced charge recombination rates and enhanced charge extraction efficiencies. A PCE of 22.2% (certified efficiency of 21.5%) is achieved and the operational stability of the MA-free PVSCs is improved.     

Combining Efficiency and Stability in Mixed Tin–Lead Perovskite Solar Cells by Capping Grains with an Ultrathin 2D Layer

The development of narrow-bandgap (E_g ≈ 1.2 eV) mixed tin–lead (Sn–Pb) halide perovskites enables all-perovskite tandem solar cells. Whereas pure-lead halide perovskite solar cells (PSCs) have advanced simultaneously in efficiency and stability, achieving this crucial combination remains a challenge in Sn–Pb PSCs. Here, Sn–Pb perovskite grains are anchored with ultrathin layered perovskites to overcome the efficiency-stability tradeoff. Defect passivation is achieved both on the perovskite film surface and at grain boundaries, an approach implemented by directly introducing phenethylammonium ligands in the antisolvent. This improves device operational stability and also avoids the excess formation of layered perovskites that would otherwise hinder charge transport. Sn–Pb PSCs with fill factors of 79% and a certified power conversion efficiency (PCE) of 18.95% are reported—among the highest for Sn–Pb PSCs. Using this approach, a 200-fold enhancement in device operating lifetime is achieved relative to the nonpassivated Sn–Pb PSCs under full AM1.5G illumination, and a 200 h diurnal operating time without efficiency drop is achieved under filtered AM1.5G illumination.