Time domain simulation of tandem silicon solar cells with optimal textured light trapping enabled by the quadratic complex rational function

H. Chung, Purdue University, Birck Nanotechnology Center
K. Y. Jung, Hanyang University
X. T. Tee, Purdue University, Birck Nanotechnology Center
Peter Bermel, Purdue University, Birck Nanotechnology Center

Date of this Version



Amorphous silicon/crystalline silicon (a-Si/c-Si) micromorph tandem cells, with best confirmed efficiency of 12.3%, have yet to fully approach their theoretical performance limits. In this work, we consider a strategy for improving the light trapping and charge collection of a-Si/c-Si micromorph tandem cells using random texturing with adjustable short-range correlations and long-range periodicity. In order to consider the full-spectrum absorption of a-Si and c-Si, a novel dispersion model known as a quadratic complex rational function (QCRF) is applied to photovoltaic materials (e. g., a-Si, c-Si and silver). It has the advantage of accurately modeling experimental semiconductor dielectric values over the entire relevant solar bandwidth from 300-1000 nm in a single simulation. This wide-band dispersion model is then used to model a silicon tandem cell stack (ITO/a-Si:H/c-Si:H/silver), as two parameters are varied: maximum texturing height h and correlation parameter f. Even without any other light trapping methods, our front texturing method demonstrates 12.37% stabilized cell efficiency and 12.79 mA/cm(2) in a 2 mu m-thick active layer. (C) 2014 Optical Society of America


Nanoscience and Nanotechnology