Semiconductor nanostructures have the potential to enhance the performance of numerous opto-electronic devices. Experimental results of quantum dot infrared photodetectors and quantum dot solar cells are presented and the effects of the carrier confinement on the device performance are discussed. Due to the limitation of current quantum dot growth techniques it is concluded that a level of control over the thermal interactions with electrons in nanostructures that would allow these devices to reach their full theoretical potential has not yet been achieved.