Outermost tensile strain dominated exciton emission in bending CdSe nanowires

Artificial modulation of electronic structures and control of the transport dynamics of carriers and excitons in CdSe nanowire are important for its application in optoelectronic nanodevices. Here, we demonstrate the aggregative flow of excitons by bending CdSe nanowires. The bending strain induces spatial variance of bandgap, and the energy bandgap gradient will result in the flow of excitons towards the bending outer edge of CdSe nanowire. The exciton emission energy shows a uniform redshift in the bending region due to the aggregative flow of excitons, and the energy redshift increases linearly with increasing the strain at the outer edge of the CdSe nanowire. Our results show an effective method to drive, concentrate, and utilize the excitons in CdSe nanowires, which provides a guide for the design of high performance and flexible optoelectronic nanodevices.