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Tin halide perovskites are the most promising candidate materials for lead‐free perovskite solar cells (PSCs) thanks to their low toxicity and ideal band gap energies. The introduction of 2D/3D mixed perovskite phases in tin‐based PSCs (TPSCs) has proven to be the most effective approach to improving device efficiency and stability. However, a 2D perovskite phase normally shows relatively low carrier mobility, which will be unfavorable for carrier transfer in the devices. In this work, we used a thiophene‐based cation 2‐(thiophen‐3‐yl)ethan‐1‐aminium (3‐TEA) as a spacer to form a novel 2D perovskite phase in TPSCs, which shows the most promising effect on the performance enhancement in comparison with other cations like 2‐(thiophen‐2‐yl)ethan‐1‐aminium (2‐TEA) and benzene‐based 2‐phenylethan‐1‐aminium (PEA). Theoretical calculations reveal that 3‐TEA enables the most compact crystal packing of [SnI6]4− octahedral layers, resulting in the lowest hole effective mass and formation energy in the 2D phase. This effect significantly enhances device efficiency and stability by facilitating more efficient carrier transfer within the 2D phase. These findings indicate that thiophene‐based 2D perovskites are well‐suited for high‐performance TPSCs. [ABSTRACT FROM AUTHOR]

Tin halide perovskites are the most promising candidate materials for lead‐free perovskite solar cells (PSCs) thanks to their low toxicity and ideal band gap energies. The introduction of 2D/3D mixed perovskite phases in tin‐based PSCs (TPSCs) has proven to be the most effective approach to improving device efficiency and stability. However, a 2D perovskite phase normally shows relatively low carrier mobility, which will be unfavorable for carrier transfer in the devices. In this work, we used a thiophene‐based cation 2‐(thiophen‐3‐yl)ethan‐1‐aminium (3‐TEA) as a spacer to form a novel 2D perovskite phase in TPSCs, which shows the most promising effect on the performance enhancement in comparison with other cations like 2‐(thiophen‐2‐yl)ethan‐1‐aminium (2‐TEA) and benzene‐based 2‐phenylethan‐1‐aminium (PEA). Theoretical calculations reveal that 3‐TEA enables the most compact crystal packing of [SnI6]4− octahedral layers, resulting in the lowest hole effective mass and formation energy in the 2D phase. This effect significantly enhances device efficiency and stability by facilitating more efficient carrier transfer within the 2D phase. These findings indicate that thiophene‐based 2D perovskites are well‐suited for high‐performance TPSCs. [ABSTRACT FROM AUTHOR]

Nanowire lasers are potential light sources that can be used in photonic integrated circuits (PICs) for inter‐chip optical communication. However, due to the size incompatibility between a nanoscale laser and a micrometer‐scale optical waveguide, their integration within a PIC remains challenging. Here, an in situ growth strategy to directly construct perovskite nanolasers inside the long polymethyl methacrylate (PMMA) fibers is explored. As the perovskite nanolasers are embedded inside the PMMA fibers, effective coupling of lasing light to the PMMA fibers is expected. Furthermore, due to the protection of PMMA coating, the perovskite nanolasers exhibit high robustness in water and demonstrate significant improvement in photostability. Stable single‐mode and polarization operations are obtained at room temperature from the lasers with a low excitation threshold. Hence, these results pave the way to realize ultra‐stable perovskite‐based PICs suitable for inter‐chip optical communication. [ABSTRACT FROM AUTHOR]

2D–3D mixed tin halide perovskites are outstanding candidate materials for lead‐free perovskite solar cells (PSCs) due to their improved stability and decreased trap density in comparison with their pure 3D counterparts. However, the mixture of multiple phases may lead to poor charge transfer across the films and limit the device efficiency. Here, a stacked quasi‐2D (down)–3D (top) double‐layered structure in perovskite films prepared via vacuum treatment is demonstrated, which can result in a planar bilayer heterojunction. In addition, it is found that the introduction of guanidinium thiocyanate (GuaSCN) additive can improve the crystallinity and carrier mobility in the 2D perovskite layer and passivate defects in the whole film, leading to a long carrier lifetime (>140 ns) in photoluminescence measurements. As a result, the PSCs show a high open circuit voltage (VOC) up to 1.01 V with a voltage loss of only 0.39 V, which represents the record values ever reported for tin‐based PSCs. The champion device exhibits a power conversion efficiency (PCE) of 13.79% with decent stability, retaining 90% of the initial PCE for 1200 h storage in N2‐filled glovebox. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites have attracted wide attention recently because of tunable optoelectronic properties and have been used as alternatives to their 3D counterparts in various optoelectronic devices. Here, a series of (PEA)2(MA)n−1PbnI3n+1 perovskite thin films is designed and fabricated by a convenient hot‐casting method to obtain gradient n in the films, which leads to the formation of vertical heterojunctions that can enhance charge separation in the films under light illumination. Based on a single gradient perovskite film, a highly sensitive and stable photodetector with a responsivity up to 149 AW−1 and a specific detectivity of 2 × 1012 Jones is obtained. This work paves a way to realizing high‐performance optoelectronic devices with enhanced charge separation by introducing compositional gradient in a perovskite film. [ABSTRACT FROM AUTHOR]

In the past several years, organic–inorganic hybrid perovskites and all inorganic perovskites have attracted enormous research interest in a variety of optoelectronic applications including solar cells, light‐emitting diodes, semiconductor lasers, and photodetectors for their plenty of appealing electrical and optoelectrical properties. Benefiting from the inherent amplification function of transistors and the pronounced photogating effect, perovskite‐based phototransistors and hybrid photodetectors can provide very high photoresponsivity and gain, rendering them highly promising for some specific applications especially ultrasensitive light detection. A review on the recent progress of phototransistors and hybrid photodetectors using perovskites as light‐sensitive materials is presented. The efforts and development in 3D and 2D perovskite‐based phototransistors, and perovskite/functional material (e.g., graphene, 2D semiconductors, organic semiconductors, and other semiconductors) heterojunction‐based hybrid photodetectors are introduced and discussed systematically. Some processing techniques for optimizing device performance are also addressed. In the final section, a conclusion of the research achievements is presented and possible challenges as well as outlook are provided to guide future activity in this research field. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskites have emerged as promising functional materials for high‐performance photodetectors. However, the toxicity of Pb and the lack of internal gain mechanism in typical perovskites significantly hinder their practical applications. Herein, a low‐voltage and high‐performance photodetector based on a single layer of lead‐free Sn‐based perovskite film is reported. The device shows broadband response from ultraviolet to near‐infrared light with a responsivity up to 105 A W−1 and a high gain at a low operating voltage. The outstanding performance is attributed to the high hole mobility, p‐doping nature, and excellent optoelectronic properties of the Sn‐based perovskite. Moreover, the device is assembled on a flexible substrate and demonstrates both high sensitivity and good bending stability. This work demonstrates a route for realizing nontoxic, low‐cost, and high‐performance perovskite photodetectors with a simple device structure. [ABSTRACT FROM AUTHOR]