S/Mo ratio and petal size controlled MoS2nanoflowers with low temperature metal organic chemical vapor deposition and their application in solar cells.

Vertically aligned two-dimensional (2D) molybdenum disulfide nanoflowers (MoS2NFs) have drawn considerable attention as a novel functional material with potential for next-generation applications owing to their inherently distinctive structure and extraordinary properties. We report a simple metal organic chemical vapor deposition (MOCVD) method that can grow high crystal quality, large-scale and highly homogeneous MoS2NFs through precisely controlling the partial pressure ratio of H2S reaction gas, PSR, to Mo(CO)6precursor, PMoP, at a substrate temperature of 250 °C. We investigate microscopically and spectroscopically that the S/Mo ratio, optical properties and orientation of the grown MoS2NFs can be controlled by adjusting the partial pressure ratio, PSR/PMoP. It is also shown that the low temperature MOCVD (LT-MOCVD) growth method can regulate the petal size of MoS2NFs through the growth time, thereby controlling photoluminescence intensity. More importantly, the MoS2NFs/GaAs heterojunction flexible solar cell exhibiting a power conversion efficiency of ~1.3% under air mass (AM) 1.5 G illumination demonstrates the utility of the LT-MOCVD method that enables the direct growth of MoS2NFs on the flexible devices. Our work can pave the way for practical, easy-to-fabricate 2D materials integrated flexible devices in optical and photonic applications.