Self‐powered photodetectors (PDs) based on inorganic metal halide perovskites are regarded as promising alternatives for the next generation of photodetectors. However, uncontrollable film growth and sluggish charge extraction at interfaces directly limit the sensitivity and response speed of perovskite‐based photodetectors. Herein, by assistance of an atomic layer deposition (ALD) technique, CsPbBr3 perovskite thin films with preferred orientation and enlarged grain size are obtained on predeposited interfacial modification layers. Thanks to improved film quality and double side interfacial engineering, the optimized CsPbBr3 (Al2O3/CsPbBr3/TiO2, ACT) perovskite PDs exhibit outstanding performance with ultralow dark current of 10−11 A, high detectivity of 1.88 × 1013 Jones and broad linear dynamic range (LDR) of 172.7 dB. Significantly, excellent long‐term environmental stability (ambient conditions >100 d) and flexibility stability (>3000 cycles) are also achieved. The remarkable performance is credited to the synergistic effects of high carrier conductivity and collection efficiency, which is assisted by ALD modification layers. Finally, the ACT PDs are successfully integrated into a visible light communication system as a light receiver on transmitting texts, showing a bit rate as high as 100 kbps. These results open the window of high performance all‐inorganic halide perovskite photodetectors and extends to rational applications for optical communication.

Interface interactions between perovskite materials and substrates are of great significance for the development of high-quality perovskite materials. Herein, we have successfully prepared Cs2AgBiBr6 double-perovskite films via a one-step spin-coating process and demonstrated a novel approach that modifies the surface of substrates with an ultrathin metal oxide (MO x ) layer to promote the film quality and photoelectric performance. Characterization results strongly suggest that the improvement is attributed to the Bi–O interfacial interaction at substrate/perovskite interface. Benefiting from this interface interaction, the average grain size of Cs2AgBiBr6 films has remarkably risen up to ∼500 nm, which is nearly four times larger than the one directly deposited on a commercial fluorine-doped tin oxide substrate. Meanwhile, the pin hole surface area ratio has reduced from 2.61 to 0.60%. Furthermore, the corresponding photodetectors (PDs) have been fabricated and the performance has significantly improved owing to the enhanced Cs2AgBiBr6 film quality. The on–off ratio of the optimized PD has a boost of almost 10 times. In addition, the minimum detected irradiation has decreased from 9.7 × 10–8 to 1.9 × 10–9 W cm–2, as well as the maximum detectivity has increased from 3.3 × 1011 to 1.2 × 1013 Jones. These results suggest a feasible method for crystallization improvement of double-perovskite films and indicate promising promotion of photoelectric performance.

Figure 2. a) Accumulated number of related articles as a function of time for the search strings given in the legend taken from ISI Web of Science. Proportion of all-inorganic perovskite solar cells are also shown. b) Relationship between champion efficiencies and the accumulated number of related articles. c) The champion power conversion efficiencies of all-inorganic perovskite solar cells along with years. The devices are classified into 5 groups by the iodine to bromine ratio quantified via the value of x. The efficiencies of hybrid perovskite solar cells are also shown for comparison. The devices with Sn doping process are not shown in the figures, because the bandgap deviates significantly from the intrinsic values. d) The champion efficiency of different all-inorganic perovskite solar cells compared with the SQ limit. The record efficiency of c-Si, GaAs and hybrid perovskite solar cells are shown for comparison.

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