Performance Stability Of Perovskite Solar Cells Research Articles

A Review on Pulsed Laser Preparation of Quantum Dots in Colloids for the Optimization of Perovskite Solar Cells: Advantages, Challenges, and Prospects.

In recent years, academic research on perovskite solar cells (PSCs) has attracted remarkable attention, and one of the most crucial issues is promoting the power conversion efficiency (PCE) and operational stability of PSCs. Generally, modification of the electron or hole transport layers between the perovskite layers and electrodes via surface engineering is considered an effective strategy because the inherent structural defects between charge carrier transport layers and perovskite layers can be reshaped and modified by adopting the functional nanomaterials, and thus the charge recombination rate can be naturally decreased. At present, large amounts of available nanomaterials for surface modification of the perovskite films are extensively investigated, mainly including nanocrystals, nanorods, nanoarrays, and even colloidal quantum dots (QDs). In particular, as unique size-dependent nanomaterials, the diverse quantum properties of colloidal QDs are different from other nanomaterials, such as their quantum confinement effects, quantum-tunable effects, and quantum surface effects, which display great potential in promoting the PCE and operational stability of PSCs as the charge carriers in perovskite layers can be effectively tuned by these quantum effects. However, preparing QDs with a neat and desirable size remains a technical difficulty, even though the present chemical engineering is highly advanced. Fortunately, the rapid advances in laser technology have provided new insight into the precise preparation of QDs. In this review, we introduce a new approach for preparing the QDs, namely pulsed laser irradiation in colloids (PLIC), and briefly highlight the innovative works on PLIC-prepared QDs for the optimization of PSCs. This review not only highlights the advantages of PLIC for QD preparation but also critically points out the challenges and prospects of QD-based PSCs.

Chemically‐Modified 2D Covalent Organic Framework as an HTL Dopant for High‐Performance, Stable, and Sustainable Perovskite Solar Cells and Modules

AbstractDespite significant advances in perovskite solar cells (PeSCs), the operational instability and susceptibility to Pb leakage of PeSCs severely limit their widespread application. To address these issues, this study investigates the effect of doping the Spiro‐OMeTAD hole‐transporting layer (HTL) with a chemically‐modified 2D conjugated covalent organic framework (Tp‐Azo‐COF) on the photovoltaic performance and stability of PeSCs. Enriched with abundant carbonyl (C═O) groups and azo (N═N) nodes, Tp‐Azo‐COF has excellent chelation and adsorption capabilities, and experimental results confirm that Tp‐Azo‐COF effectively decreases Pb leakage and Li‐ion migration, improving the environmental safety and operational stability of PeSCs. The optimized PeSCs (0.12 cm2) exhibit an efficiency of 24.25%, a new benchmark for COF‐modified devices, and maintain robust performance in large‐area modules (18 cm2) with an efficiency of 21.96%. Under accelerated aging tests, including continuous light irradiation at maximum power point tracking for 980 h, the module demonstrated exceptional durability, with near‐100% efficiency retention. The COF doping strategy developed in this study significantly enhances operational stability and minimizes Pb leakage in PeSCs, paving the way for the sustainable, large‐scale deployment of perovskite photovoltaics.

Surface Crystallization Enhancement and Defect Passivation for Efficiency and Stability Enhancement of Inverted Wide-Bandgap Perovskite Solar Cells.

Wide-bandgap (WBG) inverted perovskite solar cells (PSCs) are used as the top cell for tandem solar cells, which is an effective way to outperform the Shockley-Queisser limit. However, the low efficiency and poor phase stability still seriously restrict the application of WBG inverted PSCs. Here, the surface of the WBG perovskite film was passivated by the synthesized 1,2,4-tris(3-thienyl)benzene (THB). The THB size well matches with the halogen ion vacancy on the perovskite surface, and the S atom in THB can strongly interact with Pb2+ on the surface of the WBG perovskite film to the greatest extent, which effectively passivates surface defects and suppresses the recombination of carriers caused by these defects. At the same time, the S atom in THB occupied the migration site of the halogen ions, which inhibits the migration of halogen ions. Due to the strong conjugation effect and stability of THB, it can be locked on the surface of perovskite to increase the lattice strength and inhibit the segregation of photoinduced halide, thus improving the performance and operational stability of PSCs. The THB-modified WBG (Eg = 1.71 eV) PSC achieves a maximum power conversion efficiency of 20.75%, and its 99.0% is retained after 1512 h at a relative humidity of 10-25%. Under the irradiation of 1000 lx LED light, the indoor power conversion efficiency of the THB-modified WBG PSC reaches 34.15%.

In situ polymerization of water‐induced 1,3‐phenylene diisocyanate for enhanced efficiency and stability of inverted perovskite solar cells

AbstractIn the realm of photovoltaics, organometallic hybridized perovskite solar cells (PSCs) stand out as promising contenders for achieving high‐efficiency photoelectric conversion, owing to their remarkable performance attributes. Nevertheless, defects within the perovskite layer, especially at the perovskite grain boundaries and surface, have a substantial impact on both the overall photoelectric performance and long‐term operational stability of PSCs. To mitigate this challenge, we propose a method for water‐induced condensation polymerization of small molecules involving the incorporation of 1,3‐phenylene diisocyanate (1,3‐PDI) into the perovskite film using an antisolvent technique. Subsequent to this step, the introduction of water triggers the polymerization of [P(1,3‐PDI)], thereby facilitating the in situ passivation of uncoordinated lead defects inherent in the perovskite film. This passivation process demonstrates a notable enhancement in both the efficiency and stability of PSCs. This approach has led to the attainment of a noteworthy power conversion efficiency (PCE) of 24.66% in inverted PSCs. Furthermore, based on the P(1,3‐PDI) modification, these devices maintain 90.15% of their initial efficiency after 5000 h of storage under ambient conditions of 25°C and 50 ± 5% relative humidity. Additionally, even after maximum power point tracking for 1000 h, the PSCs modified with P(1,3‐PDI) sustain 82.05% of the initial PCE. Small molecules can rationally manipulate water and turn harm into benefit, providing new directions and methods for improving the efficiency and stability of PSCs.

Interface Engineering for Highly Efficient and Stable Perovskite Solar Cells

AbstractThe ongoing global research and development efforts on perovskite solar cells (PSCs) have led the power conversion efficiency to a high record of 26.1%. The optimization of PSC processing methods, the development of new compositions, and the introduction of passivation strategies are key factors behind the meteoric rise in performance. In particular, defect passivation and mitigation of ion migration via molecular engineering of the interfaces have played a critical role in enhancing the photovoltaic performance and operational stability of PSCs. The key interface engineering strategies enabling highly stable and efficient PSCs are focused here. The interface chemistry and the deleterious impact associated with it are discussed. The molecular design of effective modulators to mitigate the negative effects of perovskite interfaces is elaborated along with advanced characterization techniques to probe the interfaces. The progress of interface modification by multiple strategies is presented, and different modulator designs that are proven to be effective in mitigating the negative effects of perovskite interfaces are highlighted. Moreover, the main properties of effective interface modification strategies are summarized, and general design principles are deduced for future applications. Here, important insights are provided into the fields of material chemistry, physical chemistry, and optoelectronics.

Lattice Strain Regulation Enables High-Performance Formamidinium Perovskite Photovoltaics.

Formamidinium lead iodide (FAPbI3 ) perovskite possesses an ideal optical bandgap and is a potential material for fabricating the most efficient single-junction perovskite solar cells (PSCs). Nevertheless, large formamidinium (FA) cations result in residual lattice strain, which reduces the power conversion efficiency (PCE) and operational stability of PSCs. Herein, the modulation of lattice strain in FAPbI3 crystals via a π-conjugated organic amine, i.e., 4-pyrene oxy butylamine (PYBA), is proposed. PYBA pairs at the grain boundary serve as a template for the crystallization of FAPbI3 perovskite, thereby inducing a highly oriented crystal and a pure α-phase film. The PYBA pairs with strong π-π interactions provide a solid fulcrum for external compression strain, thus compensating for the inherent tension strain of FAPbI3 crystals. The strain release elevates the valence band of the perovskite crystals, thereby decreasing the bandgap and trap density. Consequently, the PYBA-regulated FAPbI3 PSC achieves an excellent PCE of 24.76%. Moreover, the resulting device exhibits improves operational stability and maintains over 80% of its initial PCE after 1500h under maximum power point tracking conditions.

Enhancing the Stability of Perovskite Solar Cells with a Multilayer Thin-Film Barrier

The long-term stability of perovskite solar cells (PSCs) remains a big challenge for the commercialization of this emerging photovoltaic technique. The protection of PSCs with a robust barrier/encapsulation could largely extend their life span. Here, we develop a multilayer thin-film barrier with the architecture of parylene/MgF2/Al2O3 as thin-film encapsulation for PSCs. The water vapor transmission rate of the multiple thin-film barriers can reach a very low value of 1 × 10–4 g m–2 d–1, comparable to that of the thin-film encapsulation in electronic packaging, making the multilayer thin-film barrier robust to block the ingress of H2O/O2 and outward leakage of perovskite decomposition byproducts. As a result, the light and thermal stability of perovskite films and the operational stability of PSCs are effectively improved with multiple thin-film barriers; especially, the encapsulated devices show negligible degradation after operation under the maximum power point tracking under 1sun illumination for 1000 h. In addition, the devices can retain 96% of their initial PCEs on average after aging for 100 h in an 85 °C-85%RH damp heat test.

Revivification of nickel oxide-perovskite interfaces via nickel nitrate to boost performance in perovskite solar cells

Nickel oxide (NiOx) is a prospective hole transporting layer (HTL) material for inverted (p-i-n) perovskite solar cells (PSCs); however, inevitable surface defects on the NiOx surface interfere with the realization of high-performance PSCs. Herein, nickel nitrate is used to eliminate defect sites and hydroxyl groups on the NiOx surface. For the first time, it is found that a uniform and ultra-thin nickel nitride (NixN) layer can be formed on the NiOx surface through the spin coating of the nickel nitrate solution at low temperatures. Promisingly, this new approach allows to overcome interface losses originating from defect sites and hydroxyl groups on the NiOx surface and to achieve high efficiency and long-term operational stability in PSCs. Furthermore, NixN serves better energy level alignment between NiOx HTL and perovskite layer, resulting in improved charge extraction and transportation and reduced charge recombination. The NixN-modified NiOx-based PSC demonstrates an outstanding efficiency of 20.45% and it shows long-term operational stability about 82% of the initial efficiency after 1000 h under ambient air conditions. Thus, this simple approach using nickel nitrate can be a promising and universal strategy to revive nickel oxide-perovskite interfaces and boost the performance and operational stability of PSCs.

Interfacial Engineering Based on Polyethylene Glycol and Cuprous Thiocyanate Layers for Efficient and Stable Perovskite Solar Cells

AbstractCuprous thiocyanate (CuSCN) is an ideal inorganic hole transport material for perovskite solar cells (PSCs). However, polar solvents for film deposition of CuSCN run a risk of destroying the perovskite light‐absorbing layer. There is also a poor contact between perovskites and CuSCN, restricting photovoltaic performance and operational stability of PSCs. In this work, a polyethylene glycol (PEG‐10000) is employed as an interlayer to effectively overcome the obstacles mentioned above. By introducing this ultra‐thin layer at the interface between (MAFA)Pb(IBr)3 and CuSCN, the power conversion efficiency (PCE) and operational stability of the related PSCs are both greatly improved. The results confirm that the insertion of PEG cannot only prevent the destruction of bulk perovskites but also reduce the traps/defects at the interface through its strong chemical bonding with undercoordinated ions, which significantly lowers the potential barrier between the perovskite and the hole transport layer. An improved PCE of 19.2% can be achieved in the CuSCN‐based PSCs by interface engineering with PEG. The introduction of PEG can also protect the perovskite film from moisture attack, and greatly enhance device stability. The PEG‐treated PSCs without encapsulation maintain more than 90% of the initial efficiency after 1860 h in the ambient air.

Synchronous Passivation of Defects with Low Formation Energies via Terdentate Anchoring Enabling High Performance Perovskite Solar Cells with Efficiency over 24%

AbstractThe ionic nature endows halide perovskites with intrinsic interfacial defects in the formed polycrystalline films, thus imposing the challenge of synchronously passivating these defects with low formation energies that directly account for the unsatisfied performance of perovskite solar cells (PSCs). By virtue of the theoretically proven capability of a three to four times enhancement of the formation energy of each defect of Pb‐I antisite (PbI) and iodine vacancy (VI), a new passivation molecule of 1,10‐phenanthrolin‐5‐amine (PAA) is intentionally explored to synchronously passivate the dual defects. The pronounced passivation effect is experimentally verified by the sharp enhancement of the open‐circuit voltage in ternary PSCs from the original 1.118 up to 1.207 V, as well as the construction of PAA‐modified formamidinium lead iodide PSCs with a champion efficiency up to 24.06%, thus providing a universal alternative of addressing interfacial charge carrier dynamics and operational stability of PSCs that are bothered by the multiple interfacial defects.

Techno-economic assessment of titanium dioxide nanorod-based perovskite solar cells: From lab-scale to large-scale manufacturing

Perovskite solar cells (PSCs) have shown remarkable progress in recent years. Different materials and structures have been developed to improve the photoconversion efficiency and operational stability of PSCs. However, the economic and technical impacts of materials and design choice on the large-scale deployment are not well addressed in the literature. In this research, a pathway for producing titanium dioxide (TiO2) nanorod-based perovskite solar modules was established and their manufacturing cost was estimated through the development of data-intensive, bottom-up techno-economic models. Material, utilities, and equipment requirements from available laboratory data to a mass production annual capacity of up to 21 MW were estimated through the development of scale factors. The minimum sustainable price and levelized cost of electricity were calculated. The direct manufacturing cost of the reference PSC module was estimated at $80.23/m2 and $0.73/W with a production capacity of 3.5 MWp. These costs decline to $47.15/m2 and $0.43/W at 21 MW production capacity. Material costs dominate the overall costs, fluorine-doped tin oxide glass being the most expensive material. The perovskite solar cell panels, when installed in residential homes in Alberta, Canada, were calculated to have a competitive levelized cost of electricity ranging from 7 to 17 cents per kWh. However, the cost was found to be extremely sensitive to the module efficiency, lifetime, and the solar insolation at the location of installation.

Unintentional passivation of 4-tertbutyl pyridine for improved efficiency and decreased operational stability of perovskite solar cells

Defect-induced nonradiative recombination limits power conversion efficiency (PCE) of organic–inorganic lead halide perovskite solar cells (PSCs). Recently, molecular passivation methods using ammonium salts and Lewis bases have been gathering tremendous attention for reducing defects at perovskite film surfaces. In this work, we find that an excess amount of 4-tert-butylpyridine (4-tBP), which is used as an additive for an organic hole transport layer, passivates surface defects of perovskite films and, therefore, improves the initial performance of PSCs. In PSCs with this 4-tBP passivation, we achieve very high open circuit voltages of >1.20 V, with a corresponding voltage deficit of 0.38 V, and PCEs of >20%. However, operational stability of PSCs under continuous illumination is greatly decreased. Thus, this work reveals that the 4-tBP passivation causes a trade-off between PCE and operational stability of PSCs.

A conjugated ligand interfacial modifier for enhancing efficiency and operational stability of planar perovskite solar cells

SnO2 is a promising alternative for TiO2 electron transporting layer (ETL), owing to the high charge mobility and chemical stability. Defects accumulating at interfaces and grain boundaries are detrimental to the performance of perovskite solar cells (PSCs). Herein, a ligand-biphenyl-3,3′,5,5′-tetracarboxylic acid butyl amine (BPTC-BN) with four carbonyls and conjugated electron is used to passivate defects at SnO2/perovskite interface. Meanwhile perovskite grown on SnO2/BPTC-BN shows increased and uniform grain size. Benefitting from decreased defects at interface and bulk perovskite, a planar PSC with a power conversion efficiency (PCE) of 21.23% and an open voltage (VOC) of 1.164 V is obtained. In contrast, devices based on single SnO2 layers deliver a PCE of 19.38% and a VOC of 1.114 V. In addition, this interface passivation strategy also improves device operational stability substantially, retaining 84% of its initial efficiency after 1000 h tracking at maximum power point (MPP). The results prove the prime importance of interface for the photovoltaic performance especially operational stability of PSCs.

The effect of current density–voltage measurement conditions on the operational stability of hybrid perovskite solar cells

Organic–inorganic lead halide perovskites have attracted great attention for use in solar cells, because of their efficient solar power conversion, along with compatibility with simple solution processing. To evaluate the operational stability of perovskite solar cells (PSCs), measurements on their current density–voltage (J−V) curves are periodically repeated in most literature studies. However, how the periodic J–V measurements affect the operational stability of PSCs has not been well understood to date. In this study, we found that repeating the J−V measurements, especially applying a voltage higher than the open-circuit voltage of PSCs, under continuous illumination, causes serious ion migration, which lowers the operational stability of PSCs. On the other hand, we observed no decrease in operational stability when the applied voltage is close to or lower than the open-circuit voltage of PSCs during the periodic J−V measurements because of the suppressed ion migration. These findings are important in evaluating the intrinsic operational stability of PSCs.

Steric Impediment of Ion Migration Contributes to Improved Operational Stability of Perovskite Solar Cells.

The operational instability of perovskite solar cells (PSCs) is known to mainly originate from the migration of ionic species (or charged defects) under a potential gradient. Compositional engineering of the "A" site cation of the ABX3 perovskite structure has been shown to be an effective route to improve the stability of PSCs. Here, the effect of size-mismatch-induced lattice distortions on the ion migration energetics and operational stability of PSCs is investigated. It is observed that the size mismatch of the mixed "A" site composition films and devices leads to a steric effect to impede the migration pathways of ions to increase the activation energy of ion migration, which is demonstrated through multiple theoretical and experimental evidence. Consequently, the mixed composition devices exhibit significantly improved thermal stability under continuous heating at 85 °C and operational stability under continuous 1 sun illumination, with an extrapolated lifetime of 2011 h, compared to the 222 h of the reference device.