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Organic–inorganic halide perovskite solar cells (PSCs) are a new class of photovoltaic devices, which have attracted increasing interests due to high efficiency, low cost, and simple fabrication process. Although a remarkable enhancement in power conversion efficiency (PCE) has been achieved in the last decade, the stability issue, including high water/heat sensitivity and UV light‐induced degradation, has become one of the main obstacles for practical applications of PSCs. Herein, hydrophobic butyl acrylate with CO and CC groups is reported as a new additive to enhance the PCE and moisture/thermal stability of CH3NH3PbI3‐based PSCs, which improves the quality of the perovskite film by promoting defect passivation, constructing a suitable energy‐level alignment, and increasing the charge carrier lifetime in PSCs. Such an additive is easily introduced into PSCs without the need for thermal treatment, which is typically required by other additives, causing a negative effect on the efficiency. The CH3NH3PbI3‐based PSC with butyl acrylate additive shows a superior PCE of 20.0%, 19% higher than that of the unmodified device (16.8%), as well as much improved moisture/thermal stability. Herein, a facile way is provided to enhance the PCE and stability of CH3NH3PbI3‐based PSCs simultaneously, which facilitates the commercialization of PSCs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are highly promising next‐generation photovoltaic devices because of the cheap raw materials, ideal band gap of ≈1.5 eV, broad absorption range, and high absorption coefficient. Although lead‐based inorganic‐organic PSC has achieved the highest power conversion efficiency (PCE) of 25.2%, the toxic nature of lead and poor stability strongly limits the commercialization. Lead‐free inorganic PSCs are potential alternatives to toxic and unstable organic‐inorganic PSCs. Particularly, double‐perovskite Cs2AgBiBr6‐based PSC has received interests for its all inorganic and lead‐free features. However, the PCE is limited by the inherent and extrinsic defects of Cs2AgBiBr6 films. Herein, an effective and facile strategy is reported for improving the PCE and stability by introducing an N719 dye interlayer, which plays multifunctional roles such as broadening the absorption spectrum, suppressing the charge carrier recombination, accelerating the hole extraction, and constructing an appropriate energy level alignment. Consequently, the optimizing cell delivers an outstanding PCE of 2.84%, much improved as compared with other Cs2AgBiBr6‐based PSCs reported so far in the literature. Moreover, the N719 interlayer greatly enhances the stability of PSCs under ambient conditions. This work highlights a useful strategy to boost the PCE and stability of lead‐free Cs2AgBiBr6‐based PSCs simultaneously, accelerating the commercialization of PSC technology. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) organic-inorganic halide perovskites have been regarded as promising sunlight harvesters for perovskite solar cells (PSCs). However, the intrinsic instability of 3D perovskites strongly limits their large-scale commercialization. Thus, the development of two-dimensional (2D) halide perovskites as light absorbers in PSCs has recently become a research hotspot, showing better stability than their 3D counterparts due to the introduction of bulky organic spacers. Among various 2D halide perovskites, Dion-Jacobson (DJ) phases exhibit a tighter connection between inorganic slabs than their Ruddlesden-Popper (RP) counterparts, leading to superior structural stability and charge transfer capability. Nevertheless, the power conversion efficiencies (PCEs) of DJ-PSCs are still inferior to their 3D counterparts. An in-time and comprehensive review of DJ perovskites as new-generation light absorbers for PSCs is presented by comparing of DJ perovskites and RP counterparts in terms of optical properties, crystal structure, charge transporting capability and energy level alignment. Furthermore, based on the summarized design criteria of halide perovskites for PSCs, several strategies are presented to improve the PCE and/or stability of DJ-PSCs. Finally, the remaining challenges and future directions for DJ-PSCs are presented and discussed. This review will provide guidelines for the fundamental understanding, design and fabrication of high-performance DJ-PSCs. [Display omitted] • The design criteria of high-performance perovskite solar cells are summarized. • Comparisons of Dion-Jacobson (DJ) perovskites and Ruddlesden-Popper counterparts for PSCs are made. • Several specific strategies to improve the performance of DJ-based PSCs are proposed. • The existing challenges and future directions of DJ-based PSCs are presented and discussed. • Keywords : Dion-Jacobson perovskite, perovskite solar cells, film quality, stability, two-dimensional perovskite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Intrinsic factors for the instability of p-PSCs from key materials are discussed. • Interfacial and bulk defects induced instability issue of p-PSCs is provided. • Several strategies to improve the stability and efficiency of p-PSCs are presented. • New cell configurations to enhance the stability of p-PSCs are briefly discussed. • The opportunities, challenges and new research directions of p-PSCs are proposed. Planar perovskite solar cells (p-PSCs) have attracted increasing attention recently due to their advantageous features of simple fabrication process, low cost and superior flexibility. Referring to the stability issue and relatively lower power conversion efficiencies (PCEs) than mesoporous PSCs, three main strategies, i.e., materials design, defect control and interfacial engineering, have been extensively applied on purpose to enhance both stability and PCEs of p-PSCs at the same time. In this review paper, a comprehensive summary of the recent advances in developing stable and efficient p-PSCs will be provided, focusing on adopting these three strategies. Firstly, the underlying origins of stability issue induced by the internal factors brought by the key materials in p-PSCs including electron transporting layers (ETLs), hole transporting layers (HTLs) and perovskite light absorbers are discussed, and then the progress in materials development towards improved stability and efficiency are summarized. Secondly, the energy loss, energy level mismatch and ionic migration problems in p-PSCs caused by the defects are discussed and recent advances in interfacial engineering and defect control are emphasized. In addition, some new and superior PSC configurations that can further enhance the stability of p-PSCs, such as ETL-free and HTL-free structures, are briefly discussed. Finally, conclusions and perspectives are provided to illustrate the opportunities and the challenges in this dynamic and frontier research field. This review will provide some useful insights for the rational design of highly stable and efficient PSCs. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite solar cells (PSCs) have become a promising candidate in the photovoltaic field due to their high power conversion efficiency and low material cost. However, the development of PSCs is limited by their poor stability under practical conditions in the presence of oxygen, moisture, sunlight, heat, and the current–voltage (I–V) hysteresis. In particular, the hysteretic I–V issue casts doubt on the validity of the photovoltaic performance results that are achieved, making it difficult to evaluate the authentic performance of PSCs. This review article focuses on understanding the I–V hysteresis behavior in PSCs and on exploring the possible reasons leading to this hysteresis phenomenon. The various strategies attempted to suppress the I–V hysteresis in PSCs are summarized, and a brief future recommendation is provided. One of the problems that restrict the further development of perovskite solar cells (PSCs) is hysteresis, making it difficult to evaluate the reliable performance of PSCs. Recent process regarding the strategies to efficiently reduce hysteresis in PSCs is reviewed. The influential factors and possible reasons are also outlined. [ABSTRACT FROM AUTHOR]