Spray-Coated
CsPbBr<sub>3</sub> Quantum Dot Films
for Perovskite Photodiodes
- Publication date
- Publisher
Abstract
Large-area
film deposition and high material utilization ratio
are the crucial factors for large-scale application of perovskite
optoelectronics. Recently, all-inorganic halide perovskite CsPbBr<sub>3</sub> has attracted great attention because of its high phase stability,
thermal stability, and photostability. However, most reported perovskite
devices were fabricated by spin-coating, suffering from a low material
utilization ratio of 1% and a small coverage area. Here, we developed
a spray-coating technique to fabricate a CsPbBr<sub>3</sub> quantum
dot (QD) film photodiode which had a high material utilization ratio
of 32% and a deposition rate of 9 nm/s. The film growth process was
studied, and substrate temperature and spray time were two key factors
for the deposition of uniform and crack-free QD films. The spray-coated
photodiode was demonstrated to be more suitable for working in the
photodetector mode because a low dark current density of 4 ×
10<sup>–4</sup> mA cm<sup>–2</sup> resulting from an
extremely low recombination current contributed to a high detectivity
of 1 × 10<sup>14</sup> Jones. A high responsivity of 3 A W<sup>–1</sup> was obtained at −0.7 V under 365 nm illumination,
resulting from a low charge-transfer resistance and a high charge
recombination resistance. We believe that the spray deposition technique
will benefit the fabrication of perovskite QD film optoelectronics
on a large scale