▎ 摘　　要

Graphene oxide (or graphene) derived graphene quantum dots (GQDs) are the primary building blocks for nano-devices because of their superior electronic, thermal, optical and toughening (in matrix) characteristics. There are various methods to prepare GQDs where top-down method has been practiced widely. This is a size reduction technique from micrometer sized graphene sheets to nanometer sized (<10nm) quantum particles with well-confined shape and quantum confinement effect. GQDs are emerging as promising optical materials for biological applications. This review will project the detailed top-down method; rather such as molecular scissoring of graphene sheets to quantum dots, optical characteristics and applications.