Numerical study of a highly efficient solar cell with graded band gap design

Abstract

A linearly graded band gap design in the intrinsic layer of a p-i-n solar cell is studied numerically. An ideal model using Matlab (R) is built and the device performance is calculated using continuity equations and an effective band gap model under various band gap combinations. The power conversion efficiency (PCE) can be as high as 30.21%, while the abrupt junction reference device only exhibits 29.25% under the same parameters. This design is also evaluated using the commercial TCAD software APSYS (R), and the calculations show optimal efficiency enhancements of about 1.14-fold that of the abrupt junction device in an AlAs/GaAs system and 2.05-fold that in an InGaN/GaN system. (C) 2015 The Japan Society of Applied Physics