The power conversion efficiency of perovskite polycrystalline thin film solar cells has rapidly increased in recent years, while the stability still lags behind due to its low thermal stability as well as the fast ion migration along the massive grain boundaries. Here, stable and efficient lateral-structure perovskite solar cells (PSCs) are achieved based on perovskite single crystals. By optimizing anode contact with a simple surface treatment, the open circuit voltage and fill factor dramatically increase and promote the efficiency of the devices exceeding 11% (0.05 to 1 Sun) compared to that of 5.9% (0.25 Sun) of the best lateral-structure single crystal PSCs previously reported. Devices show excellent operational stability and no degradation observed after 200 h continuous operation at maximum power point under 1 Sun illumination. Devices with scalable architectures are investigated by utilizing interdigital electrodes, which show huge potential to realize low cost and highly efficient perovskite photovoltaic devices.

The long‐term operational stability of perovskite light‐emitting diodes (PeLEDs), especially red PeLEDs with only several hours typically, has always faced great challenges. Stable β‐CsPbI3 nanocrystals (NCs) are demonstrated for highly efficient and stable red‐emitting PeLEDs through incorporation of poly(maleic anhydride‐alt‐1‐octadecene) (PMA) in synthesizing the NCs. The PMA can chemically interact with PbI2 in the precursors via the coupling effect between O groups in PMA and Pb2+ to favor crystallization of stable β‐CsPbI3 NCs. Meanwhile, the cross‐linked PMA significantly reduces the PbCs anti‐site defect on the surface of the β‐CsPbI3 NCs. Benefiting from the improved crystal phase quality, the photoluminescence quantum yield for β‐CsPbI3 NCs films remarkably increases from 34% to 89%. The corresponding red‐emitting PeLEDs achieves a high external quantum efficiency of 17.8% and superior operational stability with the lifetime, the time to half the initial electroluminescence intensity (T50) reaching 317 h at a constant current density of 30 mA cm−2.

signals, which offer advantages in terms of high conversion efficiency as well as high spatial resolution. [9] Conventional amorphous selenium (α-Se) has already been commercialized for direct conversion X-ray imaging of mammography. [10] However, its low mobility-lifetime (µτ) product (about 10 −7 cm 2 V −1 ) and the small atomic number generally limited the sensitivity of the detectors as well as their application in higher energy digital radiography and computed tomography scanning. [11,12] In recent years, organic and inorganic halide perovskite (OIHP) materials have been emerging as a new generation of semiconductors that are extensively used in photovoltaics, light-emitting diodes, photodetection, and radiation detection fields. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Generally, the category of OIHP can be divided into 3D and low-dimensional (LD, including 2D and 0D) ones based on their crystalline structures. Both 3D and LD OIHPs possess unique merits such as the high atomic number and low-temperature solution processibility that are highly preferred for X-ray detectors. [32][33][34][35][36] In addition, the 3D OIHPs usually exhibit a large µτ product up to ≈10 −2 cm 2 V −1 that is beneficial for realizing high sensitivity. [37] Currently, the best sandwich-structured X-ray detectors are based on the 3D triple-cation and mixed-halide OIHP (FA 0.85 MA 0.1 Cs 0.05 PbI 2.55 Br 0.45 , where FA is CH(NH 2 ) 2 , MA is CH 3 NH 3 and Cs is cesium) single crystals (SCs), with a record large sensitivity of (3.5 ± 0.2) × 10 6 µC Gy air −1 cm −2 and a minimum detectable dose of 42 nGy air s −1 at 40 keV X-ray radiation. [38] However, the 3D OIHPs generally suffer from the ion-migration induced dark current and photocurrent drift under a large electric field. In contrast, the LD OIHPs exhibit suppressed ion-migration effect and intrinsically high resistivity, which is beneficial for realizing ultralow noise and stable current output, and hence a low detection limit. [33,36,39] For instance, Zhuang et al. reported a highly sensitive X-ray detector made of layered perovskite-like (NH 4 ) 3 Bi 2 I 9 SC, and demonstrated the unique anisotropic X-ray response, effective suppression of ion migration and a low detection limit of 55 nGy air s −1 . [36] Besides, the 0D MA 3 Bi 2 I 9 SCs are demonstrated to possess ultralow dark carrier concentration of ≈10 6 cm −3 Organic-inorganic halide perovskites have exhibited bright prospects in highsensitivity X-ray detection. However, they generally suffer from the severe field-driven polarization issue that remarkably deteriorates the detection performance. Here, it is demonstrated that the interfacial electrochemical reaction between Au electrodes and halogen in MAPbI 3 single crystals (SCs) is the major source of the dark current polarization in the metal-semiconductor-metal (MSM)-structured perovskite X-ray detectors at the initial stage of biasing. By introducing the p-and n-type charge transport layers to isolate the electrodes from contacting ...

Organic-inorganic halide perovskites (OIHPs) are recognized as the promising next-generation X-ray detection materials. However, the device performance is largely limited by the ion migration issue of OIHPs. Here, we reported a simple atomistic surface passivation strategy with methylammonium iodide (MAI) to remarkably increase the ion migration activation energy of CH3NH3PbI3 single crystals. The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects, while not introducing extra mobile ions, which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100 V mm-1. The X-ray detectors hence exhibit a record-high sensitivity above 700,000 μC Gyair‐1 cm‐2 under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGyair s-1. Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.

Hybrid materials capitalize on the properties of individual materials to attain a specific combination of performance assets that is not available with the individual components alone. We describe a straightforward approach to preparation of sandwich-type hybrid dynamic materials that combine metals as electrically conductive components and polymers as bending, momentum-inducing components with flexible organic crystals as mechanically compliant and optically transducive medium. The resulting hybrid materials are conductive to both electricity and light, while they also respond to changes in temperature by deformation. Depending on the metal, their conductivity ranges from 7.9 to 21.0 S µm‒1. The elements respond rapidly to temperature by curling or uncurling in about 0.2 s, which in one typical case corresponds to exceedingly fast deformation and recovery rates of 2187.5° s‒1 and 1458.3° s‒1, respectively. In cyclic operation mode, their conductivity decreases less than 1% after 10,000 thermal cycles. The mechanothermal robustness and dual functionality favors these materials as candidates for a variety of applications in organic-based optics and electronics, and expands the prospects of application of organic crystals beyond the natural limits of their dynamic performance.

A multi-functional ionogel modified perovskite film was fabricated in situ by a R2R-compatible fabrication method and an efficiency of 21.76% was achieved in flexible solar cells with excellent operational, mechanical and water-resistant stability.

Perovskite structured CsPbX3 (X = Cl, Br, or I) quantum dots (QDs) have attracted considerable interest in the past few years due to their excellent optoelectronic properties. Surface passivation is one of the main pathways to optimize the optoelectrical performance of perovskite QDs, in which the amino group plays an important role for the corresponding interaction between lead and halide. In this work, it is found that ammonia gas could dramatically increase photoluminescence of purified QDs and effectively passivate surface defects of perovskite QDs introduced during purification, which is a reversible process. This phenomenon makes perovskite QDs a kind of ideal candidate for detection of ammonia gas at room temperature. This QD film sensor displays specific recognition behavior toward ammonia gas due to its significant fluorescence enhancement, while depressed luminescence in case of other gases. The sensor, in turn‐on mode, shows a wide detection range from 25 to 350 ppm with a limit of detection as low as 8.85 ppm. Meanwhile, a fast response time of ≈10 s is achieved, and the recovery time is ≈30 s. The fully reversible, high sensitivity and selectivity characteristics make CsPbBr3 QDs ideal active materials for room‐temperature ammonia sensing.

Doping of conjugated polyelectrolyte (PFN-Br) in MA-free perovskite resulted in a well level matching to reduce VOC loss and improve device performance, achieving a PCE of 20.32% with enhanced stability.