The aim of this experimental project is to use a pump-probe optical microscopy method1 to spatiotemporally study microscopic coherent phonon and incoherent thermal transport in nanocrystal-based optoelectronics systems. Controlling nanoscale energy carrier transport is fundamental to energy conversion applications from solar cells to LEDs. While the optical and electronic properties of colloidal nanocrystal solids have been extensively studied, phonon and heat management remain largely unexplored. To address this area, one needs a probe of local phonon transport with ultrafast to nanosecond time resolution and sub-micron spatial resolution. One also needs a way to probe microscopic temperature gradients in a material under realistic device conditions. Our approach is to combine ultrafast microscopy, nanocrystal self-assembly, optoelectronic device fabrication, and custom data processing. These studies will reveal microscopic structure–property relationships that govern energy transport.