Status and Potential of CdTe Solar-Cell Efficiency

Abstract

The status of the highest efficiency CdTe solar cells is presented in the context of comparative loss analysis among the leading technologies for single-and polycrystalline photovoltaic materials. The Shockley-Queisser limit of a single-junction cell, with acknowledgement of variations from standard conditions, is used for reference. The highest CdTe currents achieved are comparable with the best single-crystal cells and superior to other thin-film cells. Voltages match those of multicrystalline Si, but lag behind those of CIGS and crystalline Si, and considerably lag behind crystalline GaAs. The potential for still higher CdTe efficiency will likely require a combination of reduced bulk recombination, smaller back-contact barriers, device structures with advantageous internal fields, and transparent emitters with minimal band offsets.

Structural and electronic properties of CdTe1-xSex films and their application in solar cells

“…The J SC is already close to its theoretical limit [1] and the record cells by First Solar show a potential to go beyond 22% efficiency by modifying the band gap [2]. Further improvements are mainly expected from a higher doping concentration and a longer minority carrier life time.…”

Charged grain boundaries reduce the open-circuit voltage of polycrystalline solar cells—An analytical description

“…The high defect density of grain boundaries generally promotes recombination and reduces photovoltaic efficiency. However, thin film polycrystalline photovoltaics such as CdTe and Cu(In , Ga)Se 2 exhibit high efficiencies despite a large density of grain boundaries 3,4 . The unexpected high efficiency of these materials demonstrates the need for a fuller understanding of grain boundary properties, and their influence on the charge current and recombination.…”

CdTe Photovoltaics for Sustainable Electricity Generation

“…3b) While CdTe photovoltaics has shown good improvements in performance and continues to improve, its highest-achieved efficiency is significantly lower than the theoretical prediction which is attributed to lower voltage. 8 Efforts are being made to overcome this deficit at Colorado State University. Incorporating a high band gap material at the back of the CdTe cells would induce a conduction band offset which as per the modeling predictions would increase the device voltage.…”