Although epitaxial growth is the fundamental method to realize lattice matched heterojunctions in electronics manufacturing, large-scale epitaxial single crystal layers based on solution-processing have rarely been reported. Here, cascade organic−inorganic hybrid perovskite single crystals with purity quotient over 99.9% consisting of chlorine, bromine, and iodine are fabricated by solution-processed epitaxial growth, in which the mismatch rate between adjacent layers is less than 1%. The area of solution-processed epitaxial growth is proved up to 4 cm 2 , and the speed reaches nearly 100 nm s −1 . The resulting high-quality interface effectively improves bonding between adjacent layers, and the average mobility is calculated to be over 200 cm 2 V −1 s −1 in samples with different structures. Based on a specific structure with n-type, p-type, and intrinsic layers, a 7.55 mm-thickness X-ray photodiode with sensitivity 1.58 μC mGy −1 cm −2 is fabricated. This work provides a different method for fabricating solution-processed based electronic devices and makes stable perovskite-based devices more accessible.

Recently, lead (Pb) halide hybrid perovskites have emerged as sensitive X-ray detectors due to their desirable charge transport properties and high absorption of ionizing photons. This work reports on a facile methodology for fabrication of highly efficient X-ray PIN diodes based on MAPbBr 3 (MA, methylammonium; Pb, lead; Br, bromide) single crystals to detect X-ray energies ranging from 30 to 100 keV. The 2 mm thickness PIN diode exhibits a low dark current density of 20 nA cm À2 at 150 V cm À1 and high X-ray sensitivity of 23.6 μC mGy air À1 cm À2 . Besides, a large-area array based on 30 mm  28 mm  7 mm MAPbBr 3 single crystal is fabricated for X-ray imaging. When augmented with signal processing, selective higher and lower energy X-ray signals can be separated simultaneously to satisfy different requirements for soft and hard organs and tissues in one exposure. This approach offers a new pathway for a one-time radiation dose applied to the human body to achieve X-ray images for tissues and blood vessels concurrently.

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The genetic improvement of nitrogen use efficiency (NUE) of crops is vital for grain productivity and sustainable agriculture. However, the regulatory mechanism of NUE remains largely elusive. Here, we report that the rice Grain number, plant height, and heading date7 (Ghd7) gene genetically acts upstream of ABC1 REPRESSOR1 (ARE1), a negative regulator of NUE, to positively regulate nitrogen utilization. As a transcriptional repressor, Ghd7 directly binds to two Evening Element-like motifs in the promoter and intron 1 of ARE1, likely in a cooperative manner, to repress its expression. Ghd7 and ARE1 display diurnal expression patterns in an inverse oscillation manner, mirroring a regulatory scheme based on these two loci. Analysis of a panel of 2656 rice varieties suggests that the elite alleles of Ghd7 and ARE1 have undergone diversifying selection during breeding. Moreover, the allelic distribution of Ghd7 and ARE1 is associated with the soil nitrogen deposition rate in East Asia and South Asia. Remarkably, the combination of the Ghd7 and ARE1 elite alleles substantially improves NUE and yield performance under nitrogen-limiting conditions. Collectively, these results define a Ghd7-ARE1-based regulatory mechanism of nitrogen utilization, providing useful targets for genetic improvement of rice NUE.

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