A Review of Perovskites Solar Cell Stability

Additive Engineering for Efficient and Stable Perovskite Solar Cells

Halide perovskites are an intriguing class of materials that have recently attracted considerable attention for use as the active layer in thin film optoelectronic devices, including thin-film transistors, light-emitting devices, and solar cells. The “soft” nature of these materials, as characterized by their low formation energy and Young’s modulus, and high thermal expansion coefficients, not only enables thin films to be fabricated via low-temperature deposition methods but also presents rich opportunities for manipulating film formation. This comprehensive review explores how the unique chemistry of these materials can be exploited to tailor film growth processes and highlights the connections between processing methods and the resulting film characteristics. The discussion focuses principally on methylammonium lead iodide (CH3NH3PbI3 or MAPbI3), which serves as a useful and well-studied model system for examining the unique attributes of halide perovskites, but various other important members of this...

Synthetic Approaches for Halide Perovskite Thin Films.

Recently, perovskite solar cells (PSCs) have attracted much attention owing to their high power conversion efficiency (25.2%) and low fabrication cost. However, the short lifetime under operation is the major obstacle for their commercialization. With efforts from the entire PSC research community, significant advances have been witnessed to improve the device operational stability, and a timely summary on the progress is urgently needed. In this review, we first clarify the definition of operational stability and its significance in the context of practical use. By analyzing the mechanisms in established approaches for operational stability improvement, we summarize several effective strategies to extend device lifetime in a layer-by-layer sequence across the entire PSC. These mechanisms are discussed in the contexts of chemical reactions, photo-physical management, technological modification, etc., which may inspire future R&D for stable PSCs. Finally, emerging operational stability standards with respect to testing and reporting device operational stability are summarized and discussed, which may help reliable device stability data circulate in the research community. The main target of this review is gaining insight into the operational stability of PSCs, as well as providing useful guidance to further improve their operational lifetime by rational materials processing and device fabrication, which would finally promote the commercialization of perovskite solar cells.

Towards commercialization: the operational stability of perovskite solar cells

Organic–inorganic halide perovskite solar cells (PSCs) have achieved amazing progress in terms of power conversion efficiency (PCE), rising from 3.8% to over 23.3%. Owing to perovskites’ low nucleation and crystallization activation energy (56.6–97.3 kJ mol−1), a range of low temperature and large-scale solution fabrication processes have been actively investigated for potential commercialization. Although many excellent research institutes and enterprises have emerged to advance commercialization of PSCs, the performance of devices which have large areas still lag much farther behind those of smaller lab scales. The performances of PSCs are predominantly determined by the quality of the perovskite film, which in turn, is controlled by the fabrication process. A comprehensive and in-depth understanding of the nucleation and growth process during perovskite crystallization is imperative for the further advancement of large-scale manufacturing of high quality perovskite films. This review summarizes recent advances in the commercialization of the PSCs market, and critically reviews promising large-scale solution manufacturing methods combined with their physical properties and relevant challenges with the crystallization thermodynamics and kinetics of perovskites. The hurdles and challenges of commercialization and possible approaches and solutions are discussed.

From scalable solution fabrication of perovskite films towards commercialization of solar cells

Solvent engineering for high-quality perovskite solar cell with an efficiency approaching 20%

The organic–inorganic lead halide layer is a crucial factor in determining the photovoltaic performance of perovskite solar cells. Based on solvent engineering, we developed a three-step sequential coating method to prepare a high-quality CH3NH3PbI3 layer based on solvent (isopropanol) substitution. Stonehenge-like PbI2 nanostructures with controllable morphology and crystallinity were prepared by solvent substitution instead of the conventional annealing-treatment, affording several channels for CH3NH3I to penetrate into the PbI2 film due to volume expansion, and thus enabling the complete conversion from PbI2 to perovskite. In addition, the device exhibited high reproducibility by our method and achieved a high 17.78% power conversion efficiency under one-sun illumination. Furthermore, we optimized the production craft and successfully fabricated a uniform perovskite film (10 cm × 10 cm) via solvent substitution.

Solvent engineering for forming stonehenge-like PbI2 nano-structures towards efficient perovskite solar cells

Pyridine solvent engineering for high quality anion-cation-mixed hybrid and high performance of perovskite solar cells

Interface engineering with NiO nanocrystals for highly efficient and stable planar perovskite solar cells

The electron-transport layer (ETL) plays an important role in the photovoltaic performance of perovskite solar cells (PSCs), and the energy level match of functional layers can appreciably improve the power conversion efficiency (PCE) of PSCs. Herein, we choose the rare-earth europium ion Eu3+ to dope a mesoporous TiO2 ETL. X-ray diffraction, field-emission scanning electron microscopy, ultraviolet photoelectron spectroscopy, time-resolved photoluminescence, and incident-photo-to-current conversion efficiency experiments were performed to characterize the material. It is found that the Eu doping does not change the morphology, grain size, and crystallinity of TiO2. However, Eu doping upshifts the Fermi level of TiO2 ETL by scavenging oxygen atoms and introducing oxygen vacancies on the surface of the layer, which results in low series resistance and fast charge transport in the ETLs, which in turn increases the power conversion efficiency of the device from 15.85 % (undoped PSC) to 17.90 % (Eu-doped PSC). This work demonstrates an effective approach for enhancing the performance of PSCs by rare-earth doping.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ente.201700377

Tongyue Wu

Papers

Solvent engineering for high-quality perovskite solar cell with an efficiency approaching 20%

Solvent engineering for forming stonehenge-like PbI2 nano-structures towards efficient perovskite solar cells

Pyridine solvent engineering for high quality anion-cation-mixed hybrid and high performance of perovskite solar cells

Interface engineering with NiO nanocrystals for highly efficient and stable planar perovskite solar cells

Tuning the Fermi Level of TiO2 Electron Transport Layer through Europium Doping for Highly Efficient Perovskite Solar Cells