Colloidal semiconductor nanocrystals, such as CdSe nanodots, CdS nanorods have important applications in optoelectronic devices due to their excellent optical and electrical properties, such as high photoluminescence and photoluminescence efficiency and tunable emission wavelength. These applications have now been expanded to include laser diodes, lasers, displays and biomarkers. Nanodots and nanorods can be assembled to obtain nanodots heterojunction, different types of material combinations can get different types of heterojunction, and by regulating the size ratio of nanorods and nanodots can further its luminescent properties Regulation, which undoubtedly increased the regulation of nanocrystalline dimension and greatly enriched the optoelectronic properties. In recent years, there is an endless stream of research on the light emission of the nano-rod heterojunction, especially its band edge emission not only depends on its intrinsic band structure but also is controlled by the phonons. Under the phonon-assisted, the dark state of the original forbiddance transition may shift to a bright state allowed by the transition, forming a new emission peak, thus discovering many novel phenomena with edge emission. Nanocrystalline phonon mainly phonon and phonon phonon. Optical phonon is mainly determined by the interaction of nanocrystalline atoms, while acoustic phonon is heavily dependent on the shape and size of the nanocrystal. Due to the low frequency of acoustical phonons and their weak intensity, there are few studies on nanocrystals and their heterojunctions. Structural schematic of CdS nanorods (left) and CdSe / CdS rod and rod heteroj unctions (right), Raman spectra, and vibration amplitude distribution. Raman spectroscopy is an important technique to characterize phonon vibration spectra. In recent years, the State Key Laboratory of semiconductor superlattice Semiconductor Institute Tan Pingheng research group and Professor Roman Krahne of the Italian Institute of Technology under the support of the Chinese Academy of Sciences Wang Kuancheng pioneer talent program Lu Jiaxi international innovation team to use its own research group of ultra-low wave number Raman technique was used to systematically study the ultra-low frequency quantum-limited acoustic phonon of CdSe / CdS nanode-rod heterojunction under non-resonant conditions. They found that the acoustic phonon at the nano-rod heterojunction consisted mainly of telescoping modes (2 cm-1 to 10 cm-1) and radial breathing modes (10 cm-1 to 20 cm-1) The acoustic modes of the heterojunction are similar to those of the heterojunction. However, the radial breathing modes of the heterojunction show a significant redshift (2-3 cm-1) compared with that of the corresponding size nanorods. With the increase of the size of nano-dots in the heterojunction increase. Finite element simulation results show that the redshift is mainly caused by the localization of respiratory modules caused by nanodots. The nonlocal nature of the retract mode makes this redshift effect significantly diminished. Further studies show that the decrease of the average acoustic velocity induced by nanodots is the direct reason for the red-shift of the radial mode of breathing of the heterojunction quantum dots. In the modified Lamb theory, the effective volume of acoustic velocity can be obtained by introducing effective acoustic velocity. The effective volume of acoustic velocity is basically the same as the size of nanodots, which further verifies the local oscillation of breathing modes in heterojunction. The study also found that by controlling the position of the nanodots can also be controlled breathing mode vibration frequency and amplitude distribution and other properties. For the CdSe / CdS I-type heterojunction, the absorption is mainly determined by the CdS rod, and the light emission region is at the CdSe nanosphere, that is, the local area of ​​the acoustic mode is the same as the light transition position, Therefore, it is possible to control the optical transition properties of the nanometer rod heterojunction phonon-assisted phonon by controlling the particle size and position of the nanodots, which is of important reference significance for studying the light emission properties of the rod heterojunction. The research work has also been the strong support of the National Natural Science Foundation of China, the relevant research results recently published online in the American Chemical Society academic publication Nano Letters. Dr. Mario Miscuglio and Lin Miaoling co-authored the paper as co-author of the article, co-author of the article, Tan Pingheng researcher and Professor Roman Krahne.