All‐inorganic Cu‐based perovskite CsxCuyIx+y thin films are deposited with vacuum thermal evaporation using CuI and CsI mixed powder with different proportion as evaporation sources. With CuI film as buffer‐layer, the as grown CsxCuyIx+y perovskite films only have CsCu2I3 phase owing to the epitaxy on CuI layer. And the thin film quality and optoelectronic properties of CsCu2I3 are also improved. Then, metal–semiconductor–metal UV detectors based on CsCu2I3 films with Au interdigital electrodes are fabricated and the enhancement of photoresponse performance is investigated in detail. The peak responsivity and specific detectivity of the detector are 49.22 mA W−1 and 2.49 × 1012 cm Hz1/2 W−1, which are 74 and 138 times larger than that of the device without the CuI buffer‐layer, respectively.

Cu-based halide perovskite derivatives (PDs) have emerged in recent years due to their low toxicity, high stability, and earth-abundant source. In particular, due to the special photophysical properties, such as broadband visible photoluminescence (PL), large Stokes shift, and high luminous efficiency, Cs−Cu−I PDs have attracted more attention in white light and short-wavelength light-emitting device applications. Here, Cs−Cu− I nanoscale-thick films with a mixed phase of CsCu 2 I 3 and Cs 3 Cu 2 I 5 are prepared by thermal evaporation. By adjusting the proportion of the evaporation source, different phase structures and tunable PL characteristics are realized. Subsequently, with a UV light-emitting diode (310 nm) as the excitation source, standard white emission with Commission International de l'Eclairage coordinates of (0.333, 0.338) is observed when the molar ratio of CsI and CuI powders is 0.75:1. Cs−Cu−I nanoscalethick films with excellent air stability might have promising potential applications in white lighting sources.

All-inorganic lead-free perovskite C s 3 C u 2 I 5 thin films were prepared using pulsed laser deposition. Effects of the substrate temperature, laser energy, and laser frequency on the film structure and optoelectronic properties were studied. A heterojunction photodetector based on C s 3 C u 2 I 5 / n − S i was constructed, and the deep-ultraviolet photoresponse was obtained. A high I l i g h t / I d a r k ratio of 130 was achieved at − 1.3 V , and the peak response of the heterojunction photodetector was 70.8 mA/W (280 nm), with the corresponding specific detectivity of 9.44 × 10 11 c m ⋅ H z 1 / 2 ⋅ W − 1 . Moreover, the device showed good stability after being exposed to air for 30 days.

No abstract

No abstract