Advances in semiconductor technology has fueled the proliferation of a diversity of hand-held mobile computing devices. However, power consumption has become one of the fundamental barriers for deploying research systems in realistic situations. In particular, leakage power is projected to increase exponentially in future process nodes. This requires power-performance optimization at all levels of design hierarchy. In this paper, we propose to exploit the programmable threshold voltage using quantum dot (QD) transistors for addressing the challenge of energy efficiency in mobile computing systems. The unique programmability of QD transistors enhances design optimization for power-performance trade-off. Simulation results demonstrate significant leakage reduction over conventional techniques.