Representing a vast family of promising semiconductors with exceptional optical and electronic properties, metal halide perovskite materials have attracted extensive research interest and have been widely applied in solar cells, photodetectors and light emitting diodes (LEDs). In particular, as a typical low dimensional material, perovskite nanowires (NWs) and quantum wires (QWs) have shown more advantages than their thin film counterparts in optoelectronic applications. This is because of their unique anisotropic geometry, large surface-to-volume ratio, and charge carrier confinement effect. However, the lack of precise control of NWs growth and integration of NWs into large-scale arrays severely limits the development of NWs-based optoelectronics.

In this thesis, we have prese...[ Read more ]

Representing a vast family of promising semiconductors with exceptional optical and electronic properties, metal halide perovskite materials have attracted extensive research interest and have been widely applied in solar cells, photodetectors and light emitting diodes (LEDs). In particular, as a typical low dimensional material, perovskite nanowires (NWs) and quantum wires (QWs) have shown more advantages than their thin film counterparts in optoelectronic applications. This is because of their unique anisotropic geometry, large surface-to-volume ratio, and charge carrier confinement effect. However, the lack of precise control of NWs growth and integration of NWs into large-scale arrays severely limits the development of NWs-based optoelectronics.

In this thesis, we have presented a porous alumina membrane (PAM) template-assisted chemical vapor deposition (CVD) growth of high-density (10⁸~10⁹ cm^-2) and single-crystalline perovskite NW arrays. Benefiting from the mature development of the PAM fabrication, the perovskite NWs’ morphology, namely diameter, pitch, and length, can be precisely designed to fit different applications. The as-grown MAPbI₃ NWs have an optical bandgap of 1.57 eV, a carrier lifetime of 14.3 nm and an electron diffusion length of 155.9 nm. A proof-of-concept grayscale image sensor with total 1,024 pixels in a 9 cm² area has been demonstrated to possess the capability of capturing simple patterns. One step further, we have demonstrated a full-color and ultrahigh-resolution image sensor, with total 10,000 pixels in a 9 cm² area and good color sensitivity. It is achieved by vertically stacking three different perovskite (MAPbI₃, MAPbBr₃ and MAPbCl₃) NW arrays and doing the scan of an ultras-mall (5 × 5 μm² size) pixel.

In this thesis, we demonstrate the growth of perovskite QWs by reducing the diameter of the PAM template down from ~ 300 nm to ~ 6 nm. Benefiting from the quantum confinement, together with the surface passivation, a significant increase in the photoluminescence quantum yield (PLQY), from 0.81 % to 45.1 % for MAPbI₃ QWs, and from 0.87 % to 92 % for MAPbBr₃ QWs, has been achieved. Consequently, the QWs-based LEDs have been demonstrated to have a good performance, such as a maximum EQE of 7.3 %, a peak luminance over 30,000 cd m^-2 and T₅₀ of over 16.9 hours (peak luminance ~ 100 cd m^-2). Note that all those measurements are carried out in ambient air, which also indicates the excellent humidity-stability of perovskite QWs in the PAM template. Finally, the scalability of the LEDs, including a 3.5 cm × 5 cm display pattern and a 4-inch wafer device, is also demonstrated for the first time, with decent uniformity and brightness. These results provide a promising strategy towards practical applications of the metal halide perovskite optoelectronics.