"Internet of things" like it or not is here to stay. The idea that everything in the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that can exchange data, helping with maintenance and the coordination of tasks. Realizing that vision, however, requires transmitters that are powerful enough to broadcast to devices possible the other side of your house, but energy-efficient enough to last for months -- or even to harvest energy from heat or mechanical vibrations.
A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication.
When it's on, you want to be as efficient as possible, and when it's off, you want to really cut off the off-state power, the leakage power.
Expect a new Bluetooth transmission with an even longer-range 802.15.4 wireless-communication protocol.
While semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor. It's not much, but over time, it can make a big difference in the battery life of a device that spends most of its time sitting idle.
These are the challenges that face us.