Successful integration of semiconductor quantum dots (QDs) into real-world optoelectronic devices depends primarily on controlling the QDs’ electronic and transport properties upon their assembly into mesoscale films. While our understanding of carrier recombination in electrically isolated QDs is extensive, little is known about the dynamics of relevant transport and recombination events occurring in thin films of strongly interacting QDs. The recent development of a new device-based technique, ultrafast photocurrent spectroscopy, now enables the study of carrier transport in these QD films with picosecond time resolution. Employing this novel technique has been instrumental in developing transport and recombination models in QD films, offering a rational pathway toward tailoring their electronic properties for the intended target application. Within this context, examples of controlling carrier recombination by manipulating inter-QD coupling via chemical treatments, doping, or atomic layer deposition infilling will be discussed for achieving optimum operation of QD-based optoelectronic devices such as efficient solar cells or ultrafast photodetectors.