Organic-inorganic lead halide perovskite microcrystal (MC) films are attractive candidates for fabricating high-performance large-area self-powered photodetectors (PDs) because of their lower trap state density and higher carrier mobility than their polycrystalline counterparts and more suitability of synthesizing large lateral area films than their single-crystal counterparts. Here, we report on the fabrication of self-powered all-inorganic CsPbBr perovskite MC PDs with high detectivity, using a modified solution synthesis method. The MCs are up to about 10 μm in size, and the MC layer is also about 11 μm in thickness. Under 473 nm laser (100 mW) illumination, the CsPbBr MC PDs show responsivity values of up to 0.172 A W, detectivity values of up to 4.8 × 10 Jones, on/off ratios of up to 1.3 × 10, and linear dynamic ranges of up to 113 dB. These performances are significantly better than those of PDs based on polycrystalline perovskite thin films and comparable with those of PDs based on perovskite single crystals.

All-inorganic halide perovskite is considered as outstanding candidate of organic-inorganic hybrid perovskite due to its superior stability. However, the low solubility of precursor and uncontrollable film growth result in poor film quality and impede the application of polycrystalline films greatly. In this work it is reported on a space-confined growth strategy to overcome the low solubility and fast crystal growth disadvantages via freezing the precursor solution within the gaps of ordered polystyrene sphere templates. Then, the dense CsPbBr 3 polycrystalline films realize low trap density (3.07 × 10 12 cm −3 ) and high carrier mobility (9.27 cm 2 V −1 s −1 ) after stoichiometric modulation. Photodetectors based on these films exhibit high performance in all figures of merit. Specifically, high responsivity up to 216 A W −1 and ultrashort response time (<5 µs) are achieved, which are better than those of all the CsPbBr 3 based PDs. A record detectivity of 7.55 × 10 13 and 3.1 × 10 5 Hz −3 dB bandwidth are also achieved. This work opens the window of high quality all-inorganic halide perovskite polycrystalline films and can be extended to rational application of more optoelectronic devices including solar cells, photoelectrodes, and ray detectors.

The development of organic thin-film transistors (OTFTs) with low power consumption and high gain will advance many flexible electronics. Here, by combining solution-processed monolayer organic crystal, ferroelectric HfZrOx gating and van der Waals fabrication, we realize flexible OTFTs that simultaneously deliver high transconductance and sub-60 mV/dec switching, under one-volt operating voltage. The overall optimization of transconductance, subthreshold swing and output resistance leads to transistor intrinsic gain and amplifier voltage gain over 5.3 × 104 and 1.1 × 104, respectively, which outperform existing technologies using organics, oxides and low-dimensional nanomaterials. We further demonstrate battery-powered, integrated wearable electrocardiogram (ECG) and pulse sensors that can amplify human physiological signal by 900 times with high fidelity. The sensors are capable of detecting weak ECG waves (undetectable even by clinical equipment) and diagnosing arrhythmia and atrial fibrillation. Our sub-thermionic OTFT is promising for battery/wireless powered yet performance demanding applications such as electronic skins and radio-frequency identification tags, among many others.