Fig. 1. Study of the influence of reaction temperature on CsPb2Br5 NPLs. (a)–(c) SEM images, (d)–(f) AFM topography images, and (g)–(i) line profiles of layers.

Fig. 2. Morphology and EDS of an individual CsPb2Br5 NPL synthesized at 140°C. (a) TEM image and (b) HRTEM image. (c)–(f) Element mapping and (g) EDS spectrum.

Fig. 3. (a) XRD pattern. (b) Crystal structures of CsPb2Br5 and CsPbBr3. (c) PL and UV–vis absorption spectra. (d) PL decay traces of CsPb2Br5 NPLs.

Fig. 4. (a) Schematic of LEDs coated with CsPb2Br5 NPLs. (b) Emission spectra and (c) chromaticity coordinate variations of LEDs coated with different amount of CsPb2Br5 NPLs. (d) Emission spectra and (e) chromaticity coordinates of coated LEDs under different driving currents. The inset shows photographs of coated LEDs without and with injection current.

Fig. 5. (a) I–V curve of bare LEDs and coated LEDs. (b) Variation of FWHM and emission peak of coated LEDs under different injection currents. Luminous flux and luminous efficiency of (c) bare LEDs and (d) coated LEDs.

Fig. 6. (a) Schematic diagram of the fabricated photodetector device. (b) SEM image and (c) magnified SEM image of the device. (d) Band profile of the CsPb2Br5 NPL photodetector. (e)–(g) Current–voltage (I–V) characteristics of CsPb2Br5 NPL photodetectors without and with incident light of 405 nm by changing the bias voltage from −10 to 10 V.

Fig. 7. (a), (c), and (e) Current–time (I–T) curves of the photodetectors. (b), (d), and (f) Rise times and the decay times of the photodetectors with incident light of 405 nm at the bias of 6 V.