Fig. 1. (a) Chemical structure and simulated ESP of 3-BAS molecule. (b) Vacancies formation energies of halide for the perovskites before and after 3-BAS passivation. Calculated PDOS of the perovskites (c) w/o and (d) w/ 3-BAS molecule passivation based on a simplified model. (e) Differential charge density plot of the 3-BAS/perovskite system (isosurface value of 0.0015e/Å). In the three-dimensional plot, the yellow and green regions of charge density denote the charge accumulation and depletion, respectively.

Fig. 2. (a), (b) FT-IR spectra of S=O and C-N vibration modes of 3-BAS and 3-BAS-incorporated PbBr2. High-resolution XPS spectra of (c) S 2p, (d) Pb 4f, (e) Br 3d, and (f) Cl 2p for the control and targeted perovskite films.

Fig. 3. (a) PL and (b) UV-vis absorption spectra of the pure-blue quasi-2D control and targeted perovskite films. (c), (d) TA spectra of the quasi-2D control and targeted perovskite films with evolution time from 0.21 to 5.16 ps. (e), (f) TA kinetics probed at selected wavelengths for the pure-blue quasi-2D control and targeted perovskite films.

Fig. 4. (a) Device structure. (b) Energy level alignment. (c) Corresponding CIE coordinates of the targeted pure-blue PeLED. The inset shows the photograph of a bright working targeted device at 5 V. (d) Statistical EQEs and luminance of the control and targeted PeLEDs. (e) J-L-V and (f) J-EQE curves. EL stability of the (g) control and (h) targeted PeLEDs with increasing voltage. (i) Operational stability of the control and targeted PeLEDs.

Fig. 5. (a), (b) Schematic and actual experimental setup of the VLC system with the targeted pure-blue PeLED as the light source. (c) Transient EL of the targeted pure-blue PeLED at 3.5 V and 20 kHz with a fixed 20% duty cycle. (d) Square-wave response curves of the targeted pure-blue PeLED and commercial LED at 100 kHz. Comparison of (e) input and (f) output signals in the PeLED-assisted VLC audio transmission system. (Video 1, MP4, 20.7 MB [URL: https://doi.org/10.1117/1.AP.6.2.026002.s1]).