Comprehensive validation of Carrier Collection Efficiency in multiple quantum well solar cells: For more effective and direct evaluation of carrier transport dynamics

Carrier Collection Efficiency (CCE) is proposed as an effective evaluation measure of carrier transport in quantum nanostructure solar cells. CCE can be estimated by normalizing the illumination-induced current enhancement to its saturation value at reverse bias. The derivation procedure of CCE is experimentally validated by examining the bias-dependency of light absorption, and investigating the balance between the absorbed photons and collected carriers at reverse bias. The effect of AM1.5 bias-illumination for CCE characterization was also studied, and found to be much significant for more accurate evaluation of carrier dynamics during actual device operation under sunlight.