Band-edge photoluminescence recovery from zinc-blende CdSe nanocrystals synthesized at room temperature

Low-cost, large-scale production of highly photoluminescent semiconductor nanocrystals (NCs) is desirable for a variety of applications. In this paper we report the realization of highly photoluminescent zinc-blende CdSe nanocrystals from room-temperature water-phase synthesis, followed by low-temperature (80 ±5°C) chemical etching in a solution of 3-amino-l-propanol/ H ₂O (v/v = 10/1). X-ray diffraction (XRD) and transmission electron microscopy (TEM) data indicate that these CdSe NCs exhibit a cubic, zinc-blende crystal structure. After etching, these CdSe nanocrystals show strong band-edge photoluminescence (with quantum efficiency as high as 50%) and lack of deep-trap emissions. A high-resolution TEM investigation suggests that this etching not only removes surface irregularities, but also attacks grain boundaries. Moreover, the size distribution reduces upon progressive etching to allow photoluminescence full-width-at-half-maximum (FWHM) values as low as 30 nm.