2024_08_08_ecea115e4620b9a70113g

Passivation in perovskite solar cells: A review
过氧化物太阳能电池中的钝化：综述

Pengjun Zhao, Byeong Jo Kim, Hyun Suk Jung*
赵鹏俊、Byeong Jo Kim、Hyun Suk Jung*School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, 440-746, South Korea
成均馆大学先进材料科学与工程学院，韩国水原，440-746

A R T I C L E I N F O

Article history: 文章历史：

Received 18 November 2017
2017 年 11 月 18 日收到

Received in revised form 收到修订稿

18 December 2017 2017 年 12 月 18 日

Accepted 9 January 2018 已于 2018 年 1 月 9 日接受

Available online 1 February 2018
2018 年 2 月 1 日在线提供

Keywords: 关键词：

Passivation 钝化

Perovskite solar cell 过氧化物太阳能电池

Interface 界面

Defect states 缺陷状态

Abstract 摘要

A B S T R A C T Photovoltaic device based on inorganic-organic hybrid perovskite structured materials have been one of the brightest spotlights in the energy-conversion research field in recent years. However, due to their inherent properties and the architecture of the fabricated device, many defects trap states or carrier transport barriers are present at the interfaces between each functional layer and at the grain boundaries of the perovskite. These defects cause undesirable phenomena such as hysteresis and instability in the perovskite solar cells, which has slowed their commercialization. To address these issues, intensive research effort has been devoted recently to the development of passivation materials and approaches that can reduce the amount of interface and surface defect states in perovskite solar cells. Here, we have reviewed the state of the research progress in the development of passivation of different interfaces in the perovskite solar cell, including the interface (a) between transparent conductive oxide and electron transport material; (b) between the electron transport material and perovskite; (c) between the perovskite grains (grain boundaries); (d) between the perovskite and hole transport layer; (e) between the hole transport layer and electrode, and (f) between the electrode material and atmospheric environment. We also look into the prospects and challenges in the passivation of hybrid perovskite solar cells
A B S T R A C T 基于无机-有机混合包晶结构材料的光伏器件是近年来能源转换研究领域最耀眼的焦点之一。然而，由于其固有特性和所制造器件的结构，在各功能层之间的界面和过氧化物的晶界上存在许多缺陷陷阱态或载流子传输障碍。这些缺陷会导致包晶体太阳能电池出现滞后和不稳定等不良现象，从而延缓了其商业化进程。为了解决这些问题，近来人们致力于开发钝化材料和方法，以减少包晶体太阳能电池中界面和表面缺陷状态的数量。在此，我们回顾了开发钝化包晶太阳能电池中不同界面的研究进展，包括(a) 透明导电氧化物与电子传输材料之间的界面；(b) 电子传输材料与包晶之间的界面；(c) 包晶晶粒（晶界）之间的界面；(d) 包晶与空穴传输层之间的界面；(e) 空穴传输层与电极之间的界面；以及(f) 电极材料与大气环境之间的界面。我们还探讨了混合型过氧化物太阳能电池钝化的前景和挑战

1. Introduction 1.导言

In the five years since the first fabrication of the all solid-state perovskite solar cell (PSC) by Nam Gyu Park et al. in 2012 [1], the photoelectric conversion efficiencies (PCEs) of PSCs have experienced an explosive growth. Certified PCEs of

and

for small area PSCs with areas of

and

, respectively [2], and of

for large area of

[3] have been achieved. This remarkable achievement has resulted in PSCs being considered the most promising class of third generation photovoltaic devices to replace the currently widely used silicon solar cells.
自2012年Nam Gyu Park等人首次制造出全固态包晶体太阳能电池（PSC）[1]以来的五年间，PSC的光电转换效率（PCE）经历了爆炸式的增长。面积为

和

的小面积 PSC 的认证 PCE 分别达到了

和

[2]，而面积为

的大面积 PSC 的认证 PCE 则达到了

[3]。这一卓越成就使 PSC 被认为是最有希望取代目前广泛使用的硅太阳能电池的第三代光伏设备。

In order to commercialize PSCs, three major barriers remain to be overcome [4,5]: (a) The environmental toxicity caused by the use of Pb in PSCs, (b) their unsatisfactory stability against temperature, humidity and light exposure, and (c) the dependence of their differential

curves on the scan directions (i.e., from open circuit voltage to short circuit current or vice versa), which is the so-called "hysteresis" phenomenon [6].
要实现 PSC 的商业化，仍需克服三大障碍[4,5]：(a) PSC 中使用铅造成的环境毒性；(b) PSC 对温度、湿度和光照的稳定性不理想；(c) PSC 的差分

曲线取决于扫描方向（即从开路电压到短路电流或反之亦然），即所谓的 "滞后 "现象[6]。

The searching for Lead-free perovskite with high photovoltaic performance still has a long way to go. Theoretical investigation has
寻找具有高光电性能的无铅过氧化物还有很长的路要走。理论研究

implied that a promising perovskite absorber should exhibit high electronic dimensionality, a criterion that presently fulfilled only by Pb -based three dimensioned (3D) structured perovskite. Some reported double perovskites, such as the Ag - and Bi-based halide double perovskites are structurally 3D but electronically 0 dimensioned ( 0 D ), making it quite difficult to find promising candidates to replace the current Pb -based perovskite [7].
这意味着一种有前途的过氧化物吸收剂应表现出较高的电子维度，目前只有基于铅的三维（3D）结构过氧化物符合这一标准。一些已报道的双包晶石，如银基和铋基卤化物双包晶石，在结构上是三维的，但电子维数为 0（0 D），因此很难找到有前途的候选物质来取代目前的铅基包晶[7]。

Fortunately, research into eliminating hysteresis and improving stability has resulted in many substantial achievements recently. PSCs with low or even no hysteresis [8-13], and with outstanding stability towards temperature [14], humidity [15-19], and light exposure [20-25] have been successfully fabricated.
幸运的是，消除滞后和提高稳定性的研究最近取得了许多重大成果。目前已成功制造出低滞后甚至无滞后 [8-13]、对温度 [14]、湿度 [15-19] 和光照 [20-25] 具有出色稳定性的 PSC。

Interface passivation is one of the most commonly used and efficient strategies to improve the photovoltaic performance of PSCs.
界面钝化是提高 PSC 光伏性能最常用、最有效的策略之一。

According to International Union of Pure and Applied Chemistry (IUPAC), passivation, in physical chemistry and engineering, refers to a material becoming "passive," that is, less affected or corroded by the environment in which it will be used. Passivation involves the application of an outer layer of a shielding material as a microcoating, created by chemical reaction with the base material [26]. The transition process from the "active state" to the "passive state" by the formation of a passivating film [27]. For perovskite solar cells, passivation generally refers to either chemical passivation,
根据国际纯粹与应用化学联合会（IUPAC）的定义，在物理化学和工程学中，钝化是指材料变得 "被动"，即减少受使用环境的影响或腐蚀。钝化是指在屏蔽材料的外层涂上一层微涂层，通过与基体材料发生化学反应而形成[26]。通过形成钝化膜，实现从 "有源状态 "到 "无源状态 "的过渡过程 [27]。对于包晶体太阳能电池，钝化一般指化学钝化、
which reduces the defects trap states in order to optimize the charge transfer between various interfaces [9,28-31], or physical passivation, which isolates certain functional layers from the external environment to avoid degradation of the device.
或物理钝化，将某些功能层与外部环境隔离，以避免器件降解。

Typical PSC devices contain six main interface, including (a) the interface between the transparent conductive oxide and electron transport layer (ETL); (b) the interface between the electron transport material and perovskite; (c) the interface between the perovskite grains (grain boundaries); (d) the interface between the perovskite and hole transport layer (HTL); (e) the interface between the hole transport layer and electrode, and ( f ) the interface between the electrode material and atmospheric environment [32].
典型的 PSC 器件包含六个主要界面，包括（a）透明导电氧化物与电子传输层（ETL）之间的界面；（b）电子传输材料与包晶之间的界面；（c）包晶晶粒（晶界）之间的界面；（d）包晶与空穴传输层（HTL）之间的界面；（e）空穴传输层与电极之间的界面；以及（f）电极材料与大气环境之间的界面[32]。

In this review, we summarize the research advances of the past several years, and focus on interface passivation in perovskite solar cells, organized according to the interface classifications listed above. A brief prospective on the challenges and opportunities in passivation technology for enhancing the performance and stability of perovskites solar cells is also provided. It should be noted that in addition to perovskite solar cells, passivation strategies have also been applied to perovskite nanocrystals/quantum dots [33-35] and light emitting devices [36-39]; however, these will not be discussed here.
在这篇综述中，我们总结了过去几年的研究进展，并根据上述界面分类，重点介绍了过氧化物太阳能电池中的界面钝化技术。我们还简要展望了钝化技术在提高过氧化物太阳能电池性能和稳定性方面所面临的挑战和机遇。值得注意的是，除包晶石太阳能电池外，钝化策略还被应用于包晶石纳米晶体/量子点[33-35]和发光器件[36-39]；但在此不做讨论。

2. Passivation at the interface between ETL and perovskite
2.ETL 与包晶之间界面的钝化

2.1. Passivation of surface
2.1. 表面钝化

The most popularly used electron transfer material in perovskite solar cells is titanium dioxide

, with a planar or mesoporous structure. Due to its inherent properties, the surface trap states are highly abundant, which limits the photovoltaic performance of the resulting perovskite solar cells. In addition,

is an outstanding photocatalyst under UV light, however UV light can decompose organic groups, and thus attenuate the photovoltaic performance of perovskite solar cells under sunlight.
在过氧化物太阳能电池中，最常用的电子传递材料是具有平面或介孔结构的二氧化钛

。由于其固有特性，表面阱态非常丰富，从而限制了所制成的过氧化物太阳能电池的光电性能。此外，

在紫外光下是一种出色的光催化剂，但紫外光会分解有机基团，从而削弱透晶石太阳能电池在阳光下的光电性能。

Numerous strategies have been attempted to resolve this problem and many passivators have been utilized to eliminate the surface trap state of

. Common methods to passivate the surface trap states of

are to deposit another

layer to coat the original surface, for example,

chemical bath deposition (CBD) [40], or ultrathin

film deposited by atomic layer deposition (ALD) [41], or the deposition of an insulator layer

[42-47]).

itself can also act as a passivation layer on ZnO electron transfer material, to slow down the charge recombination rate in the ZnO layer [48]. While the above approaches can reduce the surface defects of

, the use of

as the electron transport layer in perovskite solar cells still has an apparent disadvantage. In

based perovskite solar cells, the

curves usually exhibit a large discrepancy between the reverse and forward scan directions (Fig. 1 (a)) [9], partly due to the non-equilibrium injection rate of electrons and holes at the two electrodes. This hysteresis phenomenon causes uncertainty as to true efficiency of the cells.
为解决这一问题，人们尝试了许多策略，并利用许多钝化剂来消除

的表面陷阱态。钝化

表面陷阱态的常用方法是沉积另一层

来覆盖原始表面，例如，

化学浴沉积（CBD）[40]，或通过原子层沉积（ALD）沉积超薄

膜[41]，或沉积绝缘体层

[42-47]）。

本身也可以作为氧化锌电子传输材料上的钝化层，减缓氧化锌层中的电荷重组速率 [48]。虽然上述方法可以减少

的表面缺陷，但在过氧化物太阳能电池中使用

作为电子传输层仍有明显的缺点。在基于

的过氧化物太阳能电池中，

曲线通常在反向和正向扫描方向上表现出很大的差异（图 1 (a)）[9]，部分原因是电子和空穴在两个电极上的非平衡注入率。这种滞后现象导致电池真实效率的不确定性。

To solve this issue, lithium (

) doped

was successfully developed to improve the electronic properties of the

mesoporous layer, by reducing electronic trap states. The monovalent

causes a partial reduction of

within the

lattice and passivation of the electronic defect states that act as nonradiative recombination centers [49]. Perovskite solar cells with enhanced efficiency as well as reduced hysteresis have been obtained using

doped

为了解决这个问题，我们成功地开发出了掺锂（

）的

，通过减少电子陷阱态来改善

介孔层的电子特性。单价

使

部分还原为

晶格内的

并使作为非辐射重组中心的电子缺陷态钝化 [49]。使用掺杂了

的

的过氧化物太阳能电池可以提高效率并减少滞后。

Additionally, high electron mobility materials, such as selfassembled fullerene derivatives [8,28,51,52], pyridine [53], carboxyl groups [54], or other semiconductor shell layers [55] have been developed to passivate the

surface. These materials create a physical barrier between

and the perovskite layer and decrease the

trap states, thus enhancing the efficiencies of the perovskite solar cells as well as improving their light-stability [28]. One example of effective solution using this strategy was inserting [6]-phenyl-C61-butyric acid methyl ester (PCBM) or another fullerene/graphene derivative [28,56-64] as a thin layer between

and the perovskite (Fig. 1 (b)) or as individual electron transport materials [63,65]. Because of the high carrier mobility of PCBM, hysteresis can be significantly reduced (Fig. 1 (c)). More importantly, the constant power output at the maximum power point (MPP) becomes comparable to the performance obtained from the J-V curve (Fig. 1 (d)) [9]. This is a key parameter that should be noted when using PCBM for the passivation of

surfaces. Because PCBM absorbs part of the incident illumination, slightly reducing the photo-generated current, an ultra-thin PCBM coating should be used [13].
此外，人们还开发了高电子迁移率材料，如自组装富勒烯衍生物 [8,28,51,52]、吡啶 [53]、羧基 [54] 或其他半导体外壳层 [55]，用于钝化

表面。这些材料在

和包晶石层之间形成了物理屏障，减少了

陷阱态，从而提高了包晶石太阳能电池的效率，并改善了其光稳定性 [28]。使用这种策略的一个有效解决方案是在

和包晶石之间插入 [6]- 苯基-C61-丁酸甲酯（PCBM）或其他富勒烯/石墨烯衍生物 [28,56-64] 作为薄层（图 1 (b)），或作为单独的电子传输材料 [63,65]。由于 PCBM 具有很高的载流子迁移率，因此可以显著减少滞后现象（图 1 (c)）。更重要的是，最大功率点 (MPP) 的恒定功率输出可与根据 J-V 曲线获得的性能相媲美（图 1 (d)）[9]。这是使用 PCBM 对

表面进行钝化时应注意的一个关键参数。由于 PCBM 会吸收部分入射光，从而略微降低光生电流，因此应使用超薄 PCBM 涂层 [13]。

More than the conductive interlayer, insulating polymers can form interface chemical interactions between the thin insulating layer and the perovskite films, resulting in significant improvement of the device stability while high PCE can still be maintained [66].
与导电夹层相比，绝缘聚合物能在绝缘薄层和过氧化物薄膜之间形成界面化学作用，从而显著提高器件的稳定性，同时仍能保持较高的 PCE [66]。

Sargent et al. [67] developed a contact-passivation method using a chlorine-capped

colloidal nanocrystal film that mitigated interfacial recombination and improved interface binding in planar structured perovskite solar cells. Certified efficiencies of

and

were achieved for active areas of 0.049 and

, respectively. These excellent photovoltaic performances resulted from the reduction in trap-like localized anti-site defects between

bonds by replacing them with

bonds (see Fig. 2 (a and b)). After contact doping, the hysteresis almost disappeared in Fig. 2 (c), and both the transient photocurrent decay and transient photovoltage decay lifetimes were longer in the

samples than that of in the

sample (Fig. 2 (d and e)). This analysis indicates that the strong binding at the

perovskite interface suppressed the interfacial recombination, which accounts for the superior stability of planar PSCs based on

(Fig. 2 (f-h)).
Sargent 等人[67]开发了一种接触钝化方法，使用氯封盖的

胶体纳米晶体薄膜，可减轻界面重组并改善平面结构过氧化物太阳能电池的界面结合。当活性面积为 0.049 和

时，认证效率分别达到

和

。这些优异的光伏性能得益于用

键取代

键，从而减少了

键之间的陷阱状局部反位缺陷（见图 2（a 和 b））。接触掺杂后，图 2 (c) 中的滞后现象几乎消失，而且

样品的瞬态光电流衰减和瞬态光电压衰减寿命均长于

样品（图 2 (d 和 e)）。这一分析表明，

包晶界面的强结合抑制了界面重组，这也是基于

的平面 PSCs 具有出色稳定性的原因（图 2 (f-h)）。

2.2. Interface passivation by self-assembled monolayer
2.2.通过自组装单层实现界面钝化

Self-assembled monolayers (SAMs) of organic molecules are molecular assemblies that form spontaneously on surfaces by adsorption and are organized into ralatively large ordered domains [68]. SAMs can be formed on semiconductors or on other dielectric substrates, and have been used in a variety of technological applications [69-72]. SAMs containing different functional groups have been utilized to passivate the interface between the electron transfer and perovskite layer [73-76]. Zuo et al. studied four SAMs (BA-SAMs, PA-SAMs, CBA-SAMs, ABA-SAMs, and C3-SAMs, see Fig. 3 (a)) on

compact planar layers [74]. The chemical groups of the different SAMs exhibited two different interactions with the

and perovskite layers: van der Waals interactions with benzoic acid (BA) and dipolar interactions with the 4 pyridinecarboxylic acid (PA), 3-aminopropanoic acid (C3) [75], 4aminobenzoic acid (ABA), or 4 -cyanobenzoic acid (CBA). As seen in Fig. 3 (b), the work functions of the SAMs showed a negative correlation with the efficiencies of the corresponding perovskite solar cells, which is the opposite of what would be expected from the energy level alignment theory. The photoluminescence (PL) quenching exhibited the same tendency as the efficiency, as shown in Fig. 3 (c) and (d). These results indicate that the interfacial optoelectronic properties were mainly governed by chemical interactions, rather than the energy level alignment. The PA-SAM passivated cell exhibited the highest efficiency of

. To explain this, the schematic diagram in Fig. 3 (f) shows the carrier dynamics of the transfer stages and the mechanism of enhanced photovoltaic performance in the PA-SAM devices. Firstly, in order to generate a
有机分子的自组装单分子层（SAMs）是通过吸附作用在表面上自发形成的分子集合体，并组织成相对较大的有序结构域[68]。SAM 可在半导体或其他电介质基底上形成，已被用于多种技术应用中 [69-72]。含有不同官能团的 SAM 被用来钝化电子转移层和包晶层之间的界面 [73-76]。Zuo 等人研究了

紧凑型平面层上的四种 SAM（BA-SAM、PA-SAM、CBA-SAM、ABA-SAM 和 C3-SAM，见图 3 (a)）[74]。不同 SAM 的化学基团与

层和包晶层有两种不同的相互作用：与苯甲酸（BA）的范德华相互作用和与 4-吡啶甲酸（PA）、3-氨基丙酸（C3）[75]、4-氨基苯甲酸（ABA）或 4-氰基苯甲酸（CBA）的双极相互作用。如图 3 (b) 所示，SAM 的功函数与相应的包光体太阳能电池的效率呈负相关，这与能级排列理论的预期相反。如图 3 (c) 和 (d) 所示，光致发光（PL）熄灭与效率呈现出相同的趋势。这些结果表明，界面光电特性主要受化学相互作用而非能级排列的影响。PA-SAM 钝化电池的效率

最高。为了解释这一点，图 3 (f) 中的示意图显示了 PA-SAM 器件中转移阶段的载流子动力学以及光伏性能增强的机理。首先，为了产生

Fig. 1. (a) A typical hysteresis J-V loop for a perovskite solar cell. (b) Electronic band structure of the PCBM passivated device (c) J-V curve showing reduced hysteresis after PCBM interposition and (d) a static PCE scan with the voltage held at the MPP voltage. Open squares represent the device without PCBM, while closed circles indicate the device with a PCBM layer.
图 1. (a) 典型的过氧化物太阳能电池滞后 J-V 曲线。(b) PCBM 钝化器件的电子带结构 (c) J-V 曲线显示 PCBM 填充后滞后现象的减少；(d) 电压保持在 MPP 电压时的静态 PCE 扫描。开放的正方形表示没有 PCBM 的器件，而封闭的圆形表示有 PCBM 层的器件。

photocurrent, the photo-generated carriers must be transferred from the perovskite to the electrode. There are two trap-stateinduced barriers that reduce the charge injection efficiency: PL quenching via trap states, and charge recombination via trap states. In most cases, the terminal groups of SAM contain nitrogen atoms, which tend to form hydrogen-bonding interactions

with the methylamine groups of the perovskite crystal lattice. This can improve their miscibility with the perovskite substrate, further enhancing the crystallization of perovskite and reducing surface trap states

. Therefore, modification with PA-SAM suppressed the surface trap states, as evidenced by the enhanced TPV decay time in Fig. 3 (e). Meanwhile, due to the reduced work function, carrier transfer between the perovskite and

became more efficient

.
要获得光电流，光产生的载流子必须从包晶石转移到电极上。有两种陷阱态引起的障碍会降低电荷注入效率：通过陷阱态淬火的光致发光和通过陷阱态的电荷重组。在大多数情况下，SAM 的末端基团含有氮原子，这些氮原子往往会与包晶晶格的甲胺基团形成氢键相互作用

。这可以改善它们与包晶基底的混溶性，进一步提高包晶的结晶度，减少表面陷阱态

。因此，用 PA-SAM 进行修饰可以抑制表面陷阱态，图 3 (e) 中增强的 TPV 衰减时间就是证明。同时，由于功函数降低，包晶和

之间的载流子转移

变得更加有效。

Investigations of the surface chemistry combined with timeresolved photoluminescence spectroscopy have indicated that charge recombination centers in hybrid metal-halide perovskites are almost exclusively localized on the surfaces of the crystals, rather than in the bulk [34]. Thus, passivation of these surface defects could be the most efficient method to prolong charge carrier lifetimes and further improve solar cell performance.
结合时间分辨光致发光光谱法进行的表面化学研究表明，混合金属卤化物过氧化物晶体中的电荷重组中心几乎全部位于晶体表面，而非晶体内部[34]。因此，钝化这些表面缺陷可能是延长电荷载流子寿命和进一步提高太阳能电池性能的最有效方法。

3. Passivation in perovskite grain boundaries
3.过氧化物晶界的钝化

3.1. Grain boundary self-passivation by
3.1.通过实现晶界自钝化

Controlling charge carrier trapping, which introduces competitive recombination channels, is an extremely important issue in the development of high-performance solar cells. As a kind of polycrystalline thin film, it is necessary for perovskite thin film to have a low density of charge carrier traps, at both grain boundaries and at interfaces with electron or hole extraction layers [78].
电荷载流子陷阱会引入竞争性重组通道，控制电荷载流子陷阱是开发高性能太阳能电池的一个极其重要的问题。作为一种多晶薄膜，包晶体薄膜必须在晶界以及与电子或空穴萃取层的界面上具有低密度的电荷载流子陷阱 [78]。

Supasai et al. first reported the passivation effect of a

layer on perovskites in 2013 [79]. The evidence for this effect was then investigated, by Wang et al. using femtosecond time-resolved transient absorption spectroscopy technology (fs-TA) [80]. The injection rates were found to be slowed in the presence of a greater mount of

, and carrier recombination lifetimes were also lengthened upon passivation [81,82]. Moreover, in a typical

structured perovskite solar cell, the formation of the

passivation layer is highly related to the

architecture. Mesoporous

is more likely to induce the formation of

than compact

, which leads to the passivation of perovskite grain boundaries
Supasai 等人于 2013 年首次报道了过氧化物上

层的钝化效应 [79]。随后，Wang 等人利用飞秒时间分辨瞬态吸收光谱技术（fs-TA）研究了这种效应的证据[80]。研究发现，在

装载较多的情况下，注入速率会减慢，钝化后载流子的重组寿命也会延长 [81,82]。此外，在典型的

结构的过氧化物太阳能电池中，

钝化层的形成与

结构密切相关。介孔

比致密

更有可能诱导

的形成，从而导致过氧化物晶界的钝化。

Fig. 3. (a) Schematic diagram of the SAM between

and the perovskite film. (b) Work functions and efficiencies of perovskite and organic solar cells with different SAMs. (c) Steady state and (d) transient PL spectra of the perovskite film on

with different SAMs. (e) Transient photo-voltage of perovskite solar cells with different SAMs. (f) Schematic diagram of the charge dynamics at the perovskite/

interface in perovskite solar cells: (1) Photoluminescence process, (2) PL quenching via trap states, (3) charge transfer process, (4) charge recombination via trap states, (5) power generation.
图 3. (a)

与包晶薄膜之间的 SAM 示意图。(b) 使用不同 SAM 的包晶和有机太阳能电池的功函数和效率。(c) 使用不同 SAM 的

上的包晶石薄膜的稳态和 (d) 瞬态 PL 光谱。(e) 使用不同表面活性剂的包晶太阳能电池的瞬态光电压。(f) 包晶体太阳能电池中包晶石/

界面的电荷动态示意图：(1) 光致发光过程，(2) 通过陷阱态淬灭 PL，(3) 电荷转移过程，(4) 通过陷阱态进行电荷重组，(5) 发电。

(Fig. 4 and Table 1). A systematical study indicated that the present of suitable amount of

species in the

film led to improved carrier behavior, possibly due to reduced recombination at the grain boundaries (GBs) and the

perovskite interface.
(图 4 和表 1）。系统研究表明，

薄膜中含有适量的

物种可改善载流子行为，这可能是由于晶界（GBs）和

包晶界面的重组减少所致。
Before passivation with

, the trap density of

was

. This value decreased to

after

passivation, suggesting that the

surface traps can be passivated by

bonding [83]. Additionally, the properties of GBs of the perovskite film were
在使用

钝化之前，

的陷阱密度为

。在

钝化后，该值降至

，这表明

表面陷阱可以通过

键来钝化 [83]。此外，还研究了过氧化物薄膜的 GB 特性。

Fig. 2. (a) Trap-like localized antisite defects form near the valence band edge of the

-terminated

perovskite interface (left). Shallow and delocalized

anti-site defects are seen for the

-terminated interface (right). (b) Device structure and cross-sectional scanning electron microscopy (SEM) image of planar PSC. (c)

curves of PSCs containing

and

as ESLs measured at reverse and forward scans. (d) Normalized transient photocurrent decay and (e) normalized transient photovoltage decay of solar cells containing

and

as ESLs. (f)

curves of the best-performing small-area (

) CsMAFA PSC measured using reverse and forward scans. (g) Dark storage stability of non-encapsulated PSCs containing

and

. The unsealed cells were kept in a dry cabinet (

relative humidity) in the dark and measured regularly under nitrogen. (h)

curves of PSC (CSMAFA) at various stages: fresh, immediately after 500 h of MPP operation, and after recovery overnight in the dark.
图 2. (a) 在

端

包晶界面（左）的价带边缘附近形成陷阱状局部反位缺陷。在

端接的

包晶界面（右图）上，可以看到浅层和分散的

反位缺陷。(b) 平面 PSC 的器件结构和横截面扫描电子显微镜 (SEM) 图像。(c) 在反向和正向扫描时测量的含有

和

ESL 的 PSC 的

曲线。(d) 含有

和

作为 ESL 的太阳能电池的归一化瞬态光电流衰减和 (e) 归一化瞬态光电压衰减。(f) 使用反向和正向扫描测量的性能最佳的小面积 (

) CsMAFA PSC 的

曲线。(g) 含有

和

的非封装 PSC 的暗储存稳定性。将未封装的电池置于干燥柜（

相对湿度）中暗处保存，并在氮气环境下定期测量。(h) PSC（CSMAFA）在不同阶段的

曲线：新鲜、MPP 运行 500 小时后立即和在黑暗中过夜恢复后。

Fig. 4. Transient band edge bleaching kinetics (symbols) and their fits (lines) for A-D perovskite architectures (inset) at the probe wavelengths

noted in Table 1. Reprinted with permission from Ref. [80]. Copyright 2016 American Chemical Society.
图 4.表 1 中所示探针波长

Table 1 表 1

Kinetic fitting parameters for the perovskite architectures.
过氧化物结构的动力学拟合参数。

Architecture 建筑学
perovskite/FTO 珍珠岩/FTO	748
perov/comp/FTO	750
perov/meso/FTO	728
perov/meso/comp/FTO	722

altered by passivation [81]. Several possible passivation mechanisms were proposed (Fig. 5) [81,84] based on the fact that the interface between

and perovskite in the film shows a type I band edge alignment. The schematic

structure is shown at the bottom left of Fig. 5 (a). The perovskite

interface (I) is shown at the top right of Fig. 5 (a); the recombination of the electrons from

and holes from the perovskite is reduced by the introduction of

. The perovskite/HTM interface (II) described at the bottom right of Fig. 5 (a); the presence of

changes the grain-to-grain boundary-bending from downward to upward, which helps to reduce recombination between the electrons from the perovskite and the holes from the HTM.
钝化改变[81]。根据薄膜中

与包晶之间的界面呈现 I 型带边排列这一事实，提出了几种可能的钝化机制（图 5）[81,84]。图 5 (a) 左下方显示了

结构示意图。包晶

界面 (I) 如图 5 (a) 右上方所示；通过引入

减少了来自

的电子和来自包晶的空穴的重组。图 5 (a) 右下方描述的包晶/HTM 界面 (II)；

的存在使晶粒间的边界弯曲从向下变为向上，这有助于减少来自包晶的电子和来自 HTM 的空穴之间的重组。

Some other reports in the literature have asserted that energy level alignment is the key factor for the passivation effect of

. Due to band edge matching between

, and the perovskite,

is able to passivate the

interface and further decrease hole recombination (Fig. 5 (b)). Moreover,

can facilitate electron injection into

Passivation in perovskite solar cells: A review 过氧化物太阳能电池中的钝化：综述

A R T I C L E I N F O

Article history: 文章历史：

Keywords: 关键词：

Abstract 摘要

1. Introduction 1.导言

2. Passivation at the interface between ETL and perovskite2.ETL 与包晶之间界面的钝化

2.1. Passivation of surface2.1. 表面钝化

2.2. Interface passivation by self-assembled monolayer2.2.通过自组装单层实现界面钝化