一片小毛肚

Achieving multifunctional encapsulation is critical to enabling perovskite solar cells (PSCs) to withstand multiple factors in real-world environments, including moisture, UV irradiation, hailstorms, etc. This work develops a two-step and economical encapsulation strategy with shellac to protect PSCs under various accelerated degradation experiments. This strategy not only enables PSCs to pass outdoor stability, UV preconditioning, and hail tests according to the International Electrotechnical Commission 61215 standard (IEC61215) but also significantly reduces lead leakage. This simple, cost-effective, and multifunctional encapsulation strategy increases the commercial prospects of perovskite solar cells.

Publication date: April 2024

Source: Journal of Energy Chemistry, Volume 91

Author(s): Haikuo Guo, Fuhua Hou, Xuli Ning, Xiaoqi Ren, Haoran Yang, Rui Liu, Tiantian Li, Chengjun Zhu, Ying Zhao, Wei Li, Xiaodan Zhang

In perovskite solar cells (PSCs), engineering the interface between perovskite absorber thin films and charge transport layers has been pivotal. Self-assembled monolayers (SAMs) in the electron-blocking layer have improved contact efficiency, reducing interfacial recombination. SAM growth models and plasma treatment for conformal SAM growth are investigated, suppressing non-radiative recombination. This approach achieves 24.5% power conversion efficiency (stabilized at 23.5%) in inverted PSCs.

Abstract

Significant advancements in perovskite solar cells (PSCs) have been driven by the engineering of the interface between perovskite absorbers and charge transport layers. Inverted PSCs offer substantial potential with their high power conversion efficiency (PCE) and enhanced compatibility for tandem solar cell applications. Conventional hole transport materials like poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(triaryl amine) (PTAA) not only constrain the PSC efficiency but also elevate their fabrication costs. In the case of improving inverted structured PSCs according to the aforementioned concerns, utilizing self-assembled monolayers (SAMs) as hole-transporting layers has played a crucial role. However, the growth of self-assembled monolayers on the substrates still limits the performance and reproducibility of inverted structured PSCs. In this study, the authors delve into the growth model of SAMs on different surface morphologies. Moreover, it is found that the plasma treatment can effectively regulate the surface morphologies of substrates and achieve conformal growth of SAMs. This treatment improves the uniformity and suppresses non-radiative recombination at the interface, which leads to a PCE of 24.5% (stabilized at 23.5%) for inverted structured PSCs.

SPINBOT, a fully automated platform, integrates machine learning to optimize solution-processed perovskite thin films. It efficiently explores an intricate multi-dimensional parameter space to produce high-quality and reproducible films. As a result, the optimized film achieves an impressive 21.6% power conversion efficiency in solar cells under ambient conditions, along with excellent long-term stability.

Abstract

Simultaneously optimizing the processing parameters of functional thin films remains a challenge. The design and utilization of a fully automated platform called SPINBOT is presented for the engineering of solution-processed functional thin films. The SPINBOT is capable of performing experiments with high sampling variability through the unsupervised processing of hundreds of substrates with exceptional experimental control. Through the iterative optimization process enabled by the Bayesian optimization (BO) algorithm, the SPINBOT explores an intricate parameter space, continuously improving the quality and reproducibility of the produced thin films. This machine learning (ML)-guided reliable SPINBOT platform enables the acceleration of the optimization process of perovskite solar cells via a simple photoluminescence characterization of films. As a result, this study arrives at an optimal film that, when processed into a solar cell in an ambient atmosphere, immediately yields a champion power conversion efficiency (PCE) of 21.6% with satisfactory performance reproducibility. The unsealed devices retain 90% of their initial efficiency after 1100 h of continuous operation at 60–65 °C under metal-halide lamps. It is anticipated that the integration of robotic platforms with the intelligent algorithm will facilitate the widespread adoption of effective autonomous experimentation to address the evolving needs and constraints within the materials science research community.

Our innovative subsurface lattice reconstruction strategy enhances halide perovskite’s stability by favoring corner-sharing octahedra, reducing defects, and optimizing valence band alignment. FA0.92Cs0.08PbI3-based devices achieve a remarkable efficiency and stability. This work represents a significant advancement in developing highly efficient and stable perovskite materials for diverse applications, such as solar cells, light-emitting diodes, and lasers.

Perovskite Solar Cells

In article number 2203859, Nastaran Meftahi, Maciej Adam Surmiak, Andrew J. Christofferson, and co-workers present a methodology for efficiently exploring the vast compositional space of quasi-2D Ruddlesden-Popper perovskite solar cells using a combination of machine learning and a reproducible, combinatorial high-throughput robotic fabrication process. This methodology provides a platform for further optimization of solar cell power conversion efficiency and stability.

It is shown that using an enantiomerically pure chiral fullerene as the electron transport layer (ETL) in a perovskite solar cell (PSC) gives an enhanced power conversion efficiency and improved stability, over the racemic material. This provides strong evidence that single isomer ETLs can improve PSC performance and positions chiral fullerenes as an exciting material class moving forward.

Abstract

The rapidly advancing improvements in perovskite solar cells (PSCs) are driven, in part, by the inclusion of suitable electron transport layers (ETLs) in high performance devices. Fullerene derivatives are particularly useful ETLs in PSCs, but many of the utilized fullerenes are present as isomeric mixtures. The opportunities presented by single-isomer, single-enantiomer fullerenes in PSCs are poorly understood. Here, inverted PSCs are prepared using bis[60]phenyl-C61-butyric acid methyl ester derivative (anti)16,17-bis[60]PCBM, comparing the performance of enantiomerically pure material to the corresponding racemate. The single enantiomer devices are found to have an improved performance, giving a power conversion efficiency (PCE) of 23.2%, compared to 20.1% PCE for the racemate. It is also shown that enantiomerically pure PSC modules can be prepared with a state-of-the-art PCE of 20.1%. Such excellent performance for the single enantiomer devices is accompanied by enhanced operational stability. This study thus provides strong evidence that single isomer ETLs can provide important improvements in PSC performance and it positions chiral fullerenes as an exciting material class moving forward.

Ammonium salt is utilized in NiO as a relatively neutral stabilizer to improve the stability and hole transport capability of NiO. Inverted MAPbI₃-based perovskite solar cells based on this novel NiO exhibit high power conversion efficiency (PCE) of 19.91% with exceptionally a high V _oc of 1.13 V and excellent stability, maintaining 97% of its initial PCE after 800 h.

Abstract

Nickel oxide (NiO) is one of the promising hole-transporting materials for perovskite solar cells (PSCs). Despite the ongoing efforts to improve PSC performance with sol–gel NiO, there has been limited study on the usage and influences of stabilizers on NiO and the relevant performance of PSCs. Until now, most of the sol–gel NiO methods use chemical stabilizers based on strongly acidic or mild basic catalysts such as hydrochloric acid and monoethanolamine. However, it is evident that the remaining pH-biased stabilizers in the film aggravate device stability. Therefore, it is imperative to develop a more stable and effective NiO, which can boost the performance of PSC. Here, the relatively neutral ammonium salt is utilized in NiO solution, which can improve the hole transport capability and stability of NiO. Under the optimum salt condition, energy level and hole conductivity are modulated favorably for hole transportation. Moreover, constructive interaction between the ammonium salt and perovskite enhances interfacial properties and reduces trap-assisted recombination. Based on this novel NiO, the champion power conversion efficiency of 19.91% with an exceptionally high open-circuit voltage of 1.13 V among the reported MAPbI₃-based PSCs is demonstrated. Furthermore, NiO with salt stabilizer secures long-term device stability, maintaining 97% of initial power conversion efficiency (PCE) even after 800 h.