Straddling type sandwiched absorber based solar cell structure

Abstract

We have proposed a solar cell structure that could utilize sub-bandgap photons along with the usual above bandgap energy photons. This device configuration could achieve efficiency beyond the single bandgap solar cell limit of 33 %. A low bandgap intrinsic absorber is embedded into a high bandgap intrinsic absorber making a straddling type sandwiched configuration. Stradling type alignment and conduction band offset make a confinement region in the sandwich absorber region. This configuration is put into a p+ and n+ for providing an internal electric field. The various aspect of confinement region carrier transport, and its physical parameters controlling device performance such as thickness, position, and barrier height, are investigated. The device working in terms of recombination and net power generation is optimized. The optimal efficiency of such a structure is observed to be 43 % with high VOC and JSC values.