| dc.description.abstract | All-inorganic metal halide perovskite materials are widely used in the field of
optoelectronics, because they can adjust the energy band by adjusting the halide composition,
and then have different emission colors from deep blue chloride, green bromide to near-infrared
iodide. In the field of LED research, a wide color gamut is created from high-purity three
primary colors. Among them, blue light emitting layer can be obtained by mixed halide
perovskite with Cl and Br, but the efficiency and stability are far behind green and red one. At
present, little research about blue and green LED has been conducted in evaporation process.
Most of the research is conducted in solution process to prepare blue LEDs, and often use partial
organic cation groups(such as MA+
, FA+
and PEA+
) to improve device performance, which isn’t
all-inorganic metal halide perovskite material.
In this study, CsPbCl3 and CsPbBr3 powder is evaporated respectively with a fixed
thickness ratio by the dual-source sequential vacuum deposition, instead of the single-source
vacuum deposition to evaporate the CsPbBr3-xClx powder, and XRD, UV-vis and SEM are used
to demonstrate the advantages of dual-source sequential vacuum deposition. The obtained film
is further annealed after the deposition process to prepare a high-quality CsPbBr3-xClx
lumenescent film with PL wavelength of 463.1 nm and FWHM of 16.2 nm.
The CsPbBr3-xClx thin film is applied in the LED as the active layer, and UPS measurement
and analysis confirm the energy level position and energy level matching of the LED with the
structure of ITO /ALD-ZnO /CsPbBr3-xClx /C. In this study, annealing process, flatness,
crystallinity, hole defects and uniformity of the active layer have been improved to enhance
LED performance. Finally, the active layer of CsPbBr3-CsPbCl3-CsPbBr3 sandwich structure
obtain the maximum luminance of 289nits, CIE coordinate of (0.1363, 0.0958) and the
corresponding emission wavelength of 470.4nm at 3.9V and 691mA/cm2
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