Interface Passivation Research Articles

Spiro-OMeTAD Anchoring perovskite for gradual homojunction in stable perovskite solar cells

The role of interface energetics-modification in interface-defect passivation and optimal interface energy-level matching is assumed to be a crucial aspect. Enhancing the performance and durability of perovskite solar cells (PSCs) can be achieved through this strategy. Here, spiro-OMeTAD [2,2′,7,7′-tetrakis (N, N-di-p-methoxyphenylamine)-9,9′-spirobifluorene] has been pipetted onto the spinning perovskite precursor film via a chlorobenzene anti-solvent strategy. It is found that spiro-OMeTAD serves as not only the filler at grain boundaries, but also the coverage on perovskite’s grain, and then forms the gradual homojunction interface from perovskite to spiro-OMeTAD hole transport layer, which can make spiro-OMeTAD anchor perovskite via the reaction between Pb2+ and C-O groups to decrease the interface barrier and obtain the optimal interface energy-level match between them for hole −migration and −collection. Moreover, these fillers or coverages can prevent moisture invading perovskite. Consequently, the counterpart PSC achieves a champion efficiency of 24.46 %, and has retained more than 88 % of the initial efficiency after 224 days of storage.

Molecule-triggered strain regulation and interfacial passivation for efficient inverted perovskite solar cells

Molecule-triggered strain regulation and interfacial passivation for efficient inverted perovskite solar cells

Columnar self-assembled heteroatom bay-annulated perylene bisimide as passivating layer for high performance perovskite solar cells

The interfaces within Perovskite solar cells (PSCs) are imperative for regulating defects, managing carrier dynamics, preventing ion migration, optimizing energy band alignment, and controlling morphology. The interfaces amidst the absorber layer and the hole transport layer (HTL) pose challenges related to ineffective charge extraction and charge recombination, necessitating enhancement. Spiro-OMeTAD is commonly utilized as p-type material in the HTL of planar architecture, entailing the inclusion of diverse additives to enhance solar cell efficiency, which can restrict device performance and stability. Herein, we explore the influence of a discotic liquid crystalline (DLCs) based semiconductor, a heteroatom bay-annulated perylene bisimide (PBI-SeO10), which is derived from tri-n-alkoxy anilines. Our study examines the function of PBI-SeO10 as an interfacial passivation layer within the perovskite/Spiro-OMeTAD interface, assessing its effects on both device performance and stability. Our results indicate that integrating PBI-SeO10 as a surface passivation layer not only aids in effective hole extraction from the perovskite layer but also substantially diminishes defects, leading to an improvement in overall device performance by approximately 7 %. Furthermore, PBI-SeO10 passivation also reduces ionic/molecular species diffusion into the device and provides good moisture resistivity leading to improved device stability.

23.81%-Efficiency Flexible Inverted Perovskite Solar Cells with Enhanced Stability and Flexibility via a Lewis Base Passivation.

Lewis base molecules bind the undercoordinated lead atoms at interfaces and grain boundaries, leading to the high efficiency and stability of flexible perovskite solar cells (PSCs). We demonstrated a highly efficient, stable, and flexible PSC via interface passivation using a Lewis base of tri(o-tolyl)phosphine (TTP). It not only induced an intimate interface contact and a complete deposition of the perovskite thin layers on hole transport layers (HTLs) but also led to a better perovskite with a raised crystallinity, fewer defects, and a better morphology, including fewer gullies, high uniformity, and low roughness. Furthermore, the TTP treatments induced a good alignment of energy levels among the perovskites, HTLs, and C60. The resultant flexible inverted PSCs exhibited a high power conversion efficiency (PCE) of 23.81%, which is one of the highest PCEs among these flexible inverted PSCs. Moreover, the optimized flexible PSCs exhibited high storage stability, superior operation stability, and enhanced mechanical flexibility. This study presents an effective method to substantially raise the PCE, stability, and mechanical flexibility of the flexible inverted perovskite photovoltaics.

Fabrication of a Porous Copper/Graphite/Zirconium Oxide Hybrid Anode via Screen Printing for Lithium‐Ion Batteries

AbstractRedesigning anode structures in Li‐ion batteries (LIBs) has been a focus of research aimed at surpassing the energy density of conventional LIBs. Although anode‐free LIBs present a promising architecture, their low Coulombic efficiency is a major drawback. This paper introduces a novel hybrid anode that integrates the current collector (CC) and active materials into a single, cohesive porous structure, which supports both de/intercalation and de/plating reactions. The hybrid anode consists of a porous Cu matrix with embedded ZrO2 powders and graphite; the quantity of graphite is only a third of that present in a traditional graphite anode. The porous structure and additives enhance the electrochemical performance of the hybrid anode by minimizing the Li–electrolyte interactions, forming a stable solid–electrolyte interface and Li4Zr3O8 passivation layer, and reducing the nucleation overpotential. Especially, the unique surface morphology, characterized by a negative curvature between sintered Cu particles, lowers the diffusion potential, which further reduces the nucleation overpotential. Additionally, the periodic mesh‐imprinted top surface, created via screen printing, promotes uniform Li plating. The results demonstrate that the cycling performance and energy density offered by the fabricated hybrid anode are superior to those of conventional graphite anodes.

Tailoring perovskite crystallization and interfacial passivation in efficient, fully textured perovskite silicon tandem solar cells

Tailoring perovskite crystallization and interfacial passivation in efficient, fully textured perovskite silicon tandem solar cells

Additive and interface passivation dual synergetic strategy enables reduced voltage loss in wide-bandgap perovskite solar cells

The open-circuit voltage (VOC) loss for wide-bandgap (WBG) perovskite solar cells (PSCs) is a significant obstacle to their further development. Herein, we introduce a dual approach involving mixed potassium thiocyanate and potassium chloride (KSCN+KCl) additives combined with 2-thiophene methylamine iodine (2-ThMAI) post-passivation strategy to mitigate VOC loss in WBG PSCs. In the mixed additives, KSCN can expand the grains and reduce the grain boundary, while KCl can inhibit the migration of halogen ions, effectively preventing phase segregation in WBG perovskites under the combination of both. However, due to the substantial energy level mismatch at the perovskite/electron transport layer (ETL) interface, suppressing phase segregation alone is insufficient to reduce the VOC loss. Therefore, introducing 2-ThMAI interface passivation could uniform spatial distribution of perovskite surface potential, promote energetic alignment at perovskite/electron transport layer interface, and further reduce the VOC loss. With these optimizations, the champion WBG PSCs achieved an enhanced VOC of 1.327 V and a promising power conversion efficiency (PCE) of 19.44 %. Additionally, these modified WBG PSCs retained 94 % of their initial efficiency after 500 hours of continuous light soaking at maximum power point tracking in ambient conditions.

Effects of Al2O3 Rear Interface Passivation on the Performance of Bifacial Kesterite‐Based Solar Cells with Fluorine‐Doped Tin Dioxide Back Contact

Herein, ultrathin Al2O3 is investigated as a rear interface passivation layer for kesterite solar cells with F:SnO2 (FTO) back contact for potential performance improvement. On the passivation layer, a thin Mo layer is deposited to improve the FTO's ohmicity. Further, NaF is evaporated on the copper zinc tin sulfide (CZTS) precursors to create openings at the passivation layer and achieve Na‐induced benefits in the absorber. The CZTS absorbers deposited directly on the Al2O3‐coated FTO peel off, while those with Mo interlayer do not. For pure sulfide kesterite devices, the Al2O3 layer reduces the short‐circuit current density (JSC), resulting in poor device efficiency. On the other hand, significantly higher JSC is realized for mixed sulfide and selenide kesterite devices with Al2O3 passivation layer, with the current density–voltage curve suggesting a reduced barrier height at the rear interface. As a result, the efficiency is improved from 1.5% for devices without Al2O3 to 4.6% for those with Al2O3. Likewise, improved external quantum efficiency response is observed in the devices with passivation layer for backside and frontside illumination. Therefore, contribution of Al2O3 passivation layer to the performance of kesterite‐based solar cells is evident from the results of this study.

Silicon‐Inspired Analysis of Interfacial Recombination in Perovskite Photovoltaics

AbstractPerovskite solar cells have reached an impressive certified efficiency of 26.1%, with a considerable fraction of the remaining losses attributed to carrier recombination at perovskite interfaces. This work demonstrates how time‐resolved photoluminescence spectroscopy (TRPL) can be utilized to locate and quantify remaining recombination losses in perovskite solar cells, analogous to methods established to improve silicon solar cell passivation and contact layers. It is shown how TRPL analysis can be extended to determine the bulk and surface lifetimes, surface recombination velocity, the recombination parameter, J0, and the implied open‐circuit voltage (iVoc) of any perovskite device configuration. This framework is used to compare 18 carrier‐selective and passivating contacts commonly used or emerging for perovskite photovoltaics. Furthermore, the iVoc values calculated from the TRPL‐based framework are directly compared to those calculated from photoluminescence quantum yields and the measured solar cell Voc. This simple technique serves as a practical guide for screening and selecting multifunctional, passivating perovskite contact layers. As with silicon solar cells, most of the material and interface analysis can be done without fabricating full devices or measuring efficiency. These purely optical measurements are even preferable when studying bulk and interfacial passivation approaches, since they remove complicating effects from poor carrier extraction.

Enhancing efficiency in inverted perovskite solar cells: The role of dual-site binding ligands

Despite the rapid progress in efficiency, PSCs encounter substantial challenges regarding durability and scalability. Inverted p-i-n PSCs provide enhanced long-term operating stability over the conventional n-i-p structures but lag in PCE (Park and Zhu, 2020 [3]). This limitation is mainly due to the interface between the perovskite light-absorbing layer and charge transport materials, where energy band misalignment and energy level pinning hinder PCE. Furthermore, surface defects exacerbate these constraints. In the endeavor to improve performance of PSCs, surface passivation is crucial for reducing nonradiative recombination at the interface. A recent study by Chen et al., published in the journal Science, introduces an innovative interface passivation strategy for p-i-n PSCs that could set a new benchmark for efficiency and stability (Chen et al., 2024 [4]). This commentary assesses the potential impact of dual-site-binding ligands on PSCs and anticipates their transformative effect on the field.

Atomic-scale understanding on the influence of sliding angle on the interfacial structure and friction behavior of textured amorphous carbon films

Textured amorphous carbon (T:a-C) films have received great attention in the fields of hard drives, MEMS, and NEMS due to their excellent tribological properties. However, there is still a lack of research on the dependence of its friction behavior on different sliding angles. Especially, owing to the limitations of in-situ characterization in capturing the friction interface information, the potential friction mechanisms are still unclear. Hence, in this work T:a-C film with a rectangular shape was constructed and the impact of different sliding angles on friction behavior under dry friction condition was mainly explored through reactive molecular dynamics simulation. Results unveil that the friction properties of T:a-C films are closely dependent on the sliding angle. When the sliding angle increases from 0° to 45°, the decrease in the number of CC covalent bonds at the friction interface weakens the interfacial crosslinking effect, leading to a decrease in the friction coefficient by 20.11 %. However, as the sliding angle further increases from 45° to 90°, an increase in friction coefficient is observed, which is due to the increase of unsaturated bond content, weakening the interface passivation effect. These results reveal the friction mechanism of T:a-C films, induced by sliding angle, and effectively guide the design and technical application of textured a-C films.

Preparation and characterization of medium entropy alloy CrCoNi toughened SiC ceramics

SiC is a promising structural material for future advanced nuclear energy systems. However, the inherent brittleness and difficulty of densification of SiC limits its practical application. In this study, medium entropy alloy (CrCoNi) reinforced silicon carbide composites (CCN/SiC) were sintered at 1950–2200°C by spark plasma sintering (SPS). The influence of CCN addition on the CCN/SiC composites was investigated in terms of microstructure, mechanical and thermal properties. The results show that SiC sintered at 2200℃ has the highest density, and the addition of 7.5 wt% CCN can significantly improve the fracture toughness of SiC. Transgranular fracture, crack deflection, and premature crack termination due to interfacial passivation are considered as potential toughening mechanisms. Although the addition of CCN can degrade the thermal conductivity of SiC ceramics, it has little effect on the structural stability of the SiC matrix at high temperatures.

Peptide‐Based Ammonium Halide with Inhibited Deprotonation Enabling Effective Interfacial Engineering for Highly Efficient and Stable FAPbI3 Perovskite Solar Cells

AbstractAmmonium iodides are intensively investigated as effective interfacial passivation agents in perovskite solar cells (PSCs) while facing a major challenge of their high reactivity with perovskites that undermines the operational stability of the PSCs. Exemplified by involving rationally designed/selected peptide into the widely adopted phenethylammonium iodide (PEAI), the present work demonstrates that the bespoke peptide‐PEAI can effectively inhibit the deprotonation of ammonium iodides and thus hinder the formation of 2D perovskite, facilitating the stability enhancement in perovskite films by multi hydrogen bonding. The additional lone pair electrons provided by peptide molecules can also enhance the passivation ability of the modified layer. Attributed to the stable co‐modifier peptide‐PEAI, the small‐area FAPbI3‐based PSCs yield a high efficiency of 25.02% with robust light and thermal stabilities. Moreover, the peptide‐PEAI‐based minimodules with an efficiency of 19.06% for a total area of 36 cm2 manifested the great application potential of this co‐modification strategy in the perovskite photovoltaics.

Molecule Crowding Strategy in Polymer Electrolytes Inducing Stable Interfaces for All-Solid-State Lithium Batteries.

All-solid-state lithium batteries with polymer electrolytes suffer from electrolyte decomposition and lithium dendrites because of the unstable electrode/electrolyte interfaces. Herein, a molecule crowding strategy is proposed to modulate the Li+ coordinated structure, thus in situ constructing the stable interfaces. Since 15-crown-5 possesses superior compatibility with polymer and electrostatic repulsion for anion of lithium salt, the anions are forced to crowd into a Li+ coordinated structure to weaken the Li+ coordination with polymer and boost the Li+ transport. The coordinated anions prior decompose to form LiF-rich, thin, and tough interfacial passivation layers for stabilizing the electrode/electrolyte interfaces. Thus, the symmetric Li-Li cell can stably operate over 4360h, the LiFePO4||Li full battery presents 97.18% capacity retention in 700 cycles at 2C, and the NCM811||Li full battery possesses the capacity retention of 83.17% after 300 cycles. The assembled pouch cell shows excellent flexibility (stand for folding over 2000 times) and stability (89.42% capacity retention after 400 cycles). This work provides a promising strategy to regulate interfacial chemistry by modulating the ion environment to accommodate the interfacial issues and will inspire more effective approaches to general interface issues for polymer electrolytes.

Controlled growth of uniform and dense perovskite layers on SnO2 via interface passivation by PbS quantum dots

AbstractFormamidinium lead iodide (FAPbI3) and SnO2 are a promising pair of halide perovskite and electron transport layer (ETL). However, FAPbI3 and SnO2 have inherent problems such as high crystallization temperature of FAPbI3 and surface defects of SnO2 like oxygen vacancies. They cause low crystallinity, non‐uniform grain growth, and more interface defects, leading to carrier recombination and leakage current. The passivation of the interface between FAPbI3 and SnO2 is an effective process to address these materials issues. Herein, a dual role of lead sulfide (PbS) quantum dots (QDs) in the interface passivation is explored. PbS QDs which are introduced to the interface between FAPbI3 and ETL, link to Sn‐dangling bonds of SnO2 ETLs and anchor the iodine atoms of FAPbI3. This changes considerably lower nonradiative recombination, achieve a better energetic alignment between ETL and PbI3, and facilitate electron extraction, leading to a power conversion efficiency of 21.66%.image

Synergistic effect of In2O3 nanocuboids and TiO2 nanocubes in electron transport bilayer for carbon-based perovskite solar cells

Bilayer-based electron transport layers (ETLs) are recently emerging due to their benefits in the efficient charge carrier extraction and transportation with diminished interfacial recombination loss. Here, the carbon electrode-based perovskite solar cells (C–PSCs) with mesoscopic bilayer-oriented ETLs using In2O3 nanocuboids and varied concentrations of TiO2 nanocubes were fabricated and their performances were evaluated. In2O3 nanocuboids and TiO2 nanocubes were synthesized through hydro and solvothermal routes respectively. The synthesized samples' structural, morphological, and optical behaviours were characterized by PXRD, FESEM, HRTEM and UV–Vis spectroscopy. With pertinent studies, the impact of all the variants of bilayer-based ETLs on the formation of the perovskite layer was thoroughly investigated. The device based on monolayer ETL has achieved power conversion efficiency (PCE) of 6.9 % with current density (Jsc) of 18.69 mA/cm2. The highest PCE of 10.7 % with Jsc of 22.15 mA/cm2 was achieved for the champion device with the optimized bilayer of In2O3/TiO2 (200 mg/ml). This champion device showed ambient stability (at 35 °C with ∼70 % humidity) of 83 % from its initial PCE for 35 days without any encapsulation. Thus, the suitable morphology of the bilayer-based ETL facilitated the interface passivation by the self-embedding process, which played a significant role in the improvement of the cell performance.

Interface Passivation of a Pyridine-Based Bifunctional Molecule for Inverted Perovskite Solar Cells.

Organic-inorganic hybrid perovskite solar cells (PSCs) have recently been demonstrated to be promising renewable harvesters because of their prominent photovoltaic power conversion efficiency (PCE), although their stability and efficiency still have not reached commercial criteria. Trouble-oriented analyses showcase that defect reduction among the grain boundaries and interfaces in the prepared perovskite polycrystalline films is a practical strategy, which has prompted researchers to develop functional molecules for interface passivation. Herein, the pyridine-based bifunctional molecule dimethylpyridine-3,5-dicarboxylate (DPDC) was employed as the interface between the electron-transport layer and perovskite layer, which achieved a champion PCE of 21.37% for an inverted MAPbI3-based PSC, which was greater than 18.64% for the control device. The mechanistic studies indicated that the significantly improved performance was mainly attributed to the remarkably enhanced fill factor with a value greater than 83%, which was primarily due to the nonradiative recombination suppression offered by the passivation effect of DPDC. Moreover, the promoted carrier mobility together with the enlarged crystal size contributed to a higher short-circuit current density. In addition, an increase in the open-circuit voltage was also observed in the DPDC-treated PSC, which benefited from the improved work function for reducing the energy loss during carrier transport. Furthermore, the DPDC-treated PSC showed substantially enhanced stability, with an over 80% retention rate of its initial PCE value over 300 h even at a 60% relative humidity level, which was attributed to the hydrophobic nature of the DPDC molecule and effective defect passivation. This work is expected not only to serve as an effective strategy for using a pyridine-based bifunctional molecule to passivate perovskite interfaces to enhance photovoltaic performance but also to shed light on the interface passivation mechanism.

Graphene Oxide as an Effective Interface Passivation Layer for Enhanced Performance of Hybrid Silicon Solar Cells

Graphene Oxide as an Effective Interface Passivation Layer for Enhanced Performance of Hybrid Silicon Solar Cells

Drag force shear manipulating ligand distribution at perovskite buried interface enables efficiently suppressed EQE roll-off of perovskite light-emitting diodes

Effectively manipulating the ligand distribution at the perovskite buried interface is critical for achieving high-performance nanocrystal-based perovskite light-emitting diodes (PeLEDs). However, it is challenging to realize it due to the non-exposed feature of the buried interface. Here, the drag force shear (DFS) is utilized to successfully regulate the ligand distribution at the perovskite buried interface which can effectively suppress the EQE roll-off of devices. By manipulating the ligand distribution at the perovskite buried interface, it is revealed that a more ligand preservation could result in an improved defect passivation leading to higher EQE, while the carrier injection barrier is increased simultaneously making devices suffer from severe EQE roll-off and decreased luminance, and vice versa. With the help of optimizing the ligand distribution by manipulating the DFS, the balance between carrier injection and interfacial defect passivation is successfully achieved. Resultantly, an enhanced EQE of 17.24 % with substantially suppressed EQE roll-off is reached, culminating in a remarkable luminance of 61,900 cd/m2. This work presents an efficient approach to control ligand distribution at the perovskite buried interface and offers valuable insights for realizing high luminance and low EQE roll-off of PeLEDs.

The impact of interface recombination on the external quantum efficiency of silicon solar cells

In various types of organic/inorganic solar cells, optical response enhancement is consistently observed within the external quantum efficiency spectra owing to the improvement in interface passivation and the suppression of carrier recombination. In this study, we focused on crystalline silicon solar cells and systematically investigated the impact of interface recombination on the optical response upon dual-side illumination using numerical simulations. The results shed light on the interesting phenomenon that the surface recombination velocity has a significant impact on the external quantum efficiency, and it changes as the illumination direction changes. Moreover, from a practical perspective, the spectra of external quantum efficiency under dual-side illumination conditions can act as a powerful tool for the quick diagnosis of the passivation quality at the top and bottom interfaces.