Date of this Version
United States Patent Huang et al. Patent No.: US 10,622,161 B2
Photoelectronic devices using perovskite single-crystal materials having a narrow spectral response, e.g., with a full-width-at-half-maximum response of less than about 20 nm, are provided. The response spectra are continuously (in frequency band) settable or tunable, e.g., from blue to red, by changing the halide composition and thus the band gap of the single crystals. The narrow-band response can be explained by the strong surface charge recombination of the excess carriers lose to the crystal surfaces generated by short wavelength light. The excess carriers generated by below-band gap excitation locate away from the surfaces and can be much more efficiently collect by the electrodes to produce a photocurrent.