As promising photovoltaic devices, perovskite solar cells (PSCs) have attracted extensive and ongoing attention due to easy manufacturing and high power conversion efficiency (PCE). Although the PCE is lower than that of PSCs with normal structure, inverted PSCs have been widely investigated due to their lower hysteresis and potential application. Electron transport layer (ETL) on top of perovskite film in inverted PSCs plays a significant role in device performance. Inorganic top ETL has been used to replace organic ETL for their excellent characters. This review summarizes the progress of inorganic top ETL for high‐performance inverted PSCs. Firstly, the principles of top ETL and advantages of inorganic ETL are highlighted. Then the established top ETLs are summarized. Subsequently, various strategies for top ETL fabrication are shown to demonstrate their advantages and shortcomings. Finally, conclusion and outlook of top ETL in inverted PSCs are presented, addressing the issues and directing the hopeful solutions. image

Organic framework materials have gained attention for their intriguing structures, diverse applications, and porous materials with open frameworks.

Nanocrystals (NCs) have been widely studied owing to their distinctive properties and promising application in new-generation photoelectric devices.

As an emerging photovoltaic technology, hybrid perovskite solar cells (PSCs) have achieved excellent performance through rapid development in recent years. High power conversion efficiency (PCE) and excellent stability further promote the commercialization of PSCs. To date, the perovskite light-harvesting active materials are diversified and the device fabrication process is also various. Considered the fabrication costs and steps of PSCs based on different active materials, the quantitative valuation of different hybrid PSCs with PCE above 20% is implemented using data envelopment analysis (DEA) for the first time. This valuation mainly focuses on the inputs (cost and fabrication steps) and outputs (PCE and stability). No weights are needed during the whole analytical process. This ensures the convenience and ease of operation of the analysis, promoting the universality of this method. The results show a detailed analysis of different PSCs from an economic perspective and develop a new way to evaluate PSCs. Meanwhile, the results and this novel valuation method will provide promising guidance for the commercialization of PSCs.

GeSe, an emerging two-dimensional material, exhibits a significant potential in nonlinear optics. This study explores an effective method to enhance the nonlinear optical properties of GeSe through the utilization of a multilayer film structure. We designed and fabricated a (SiO2/ZnSe/GeSe/ZnSe)4/SiO2 multilayer film structure, which substantially augments the nonlinear optical response of GeSe via electric field enhancement and transmission spectrum edge modulation. Z-scan measurements reveal that the two-photon absorption coefficient and nonlinear refractive index of the multilayer film reach 25.616×104 cm/GW and 8.235×10−13 m2/W, representing more than a fourfold increase compared to a single GeSe film. A further analysis of optical limiting characteristics reveals onset and optical limiting thresholds of 0.043 and 0.711 GW/cm2, respectively. This multilayer film design strategy significantly enhances the nonlinear optical performance of GeSe, offering possibilities for developing high-efficiency optical modulators and optical switches based on two-dimensional materials.