Application of MEG in Increasing External Quantum Efficiency Over 100%

Abstract

This review paper focuses on increasing the efficiency of Solar cell using Quantum Dot. The principle idea is using MEG (Multiple exciton Generation). MEG is more efficient in quantum confined nanostructures than in bulk semiconductors because the momentum preservation prerequisite is relaxed. Even the carrier-carrier interactions are huge due to strong confinement. The carrier multiplication decoupling from the effective band gap allows amplified photo-voltage for corresponding carrier multiplication. Along with this, it was also found that external quantum efficiency (EQE) would reach almost 100%, sometimes even exceeding it, for energy which is greater than twice the band gap energy. This is due to the fact that high energy photons have the ability to produce more than one photo carrier pair. MEG is definitely a promising route to increasing solar cell efficiency. If a threshold of twice the band gap energy could be realized for impact ionization in a colloid Quantum Dot cell, the theoretical maximum possible conversion efficiency would shift to above 60%. The goal is to capture maximum energy incident on a given plane and targeting highyield transportation of the resultant photo generated charge.