Open AccessComplex refractive indices of Spiro-TTB and C60 for optical analysis of perovskite silicon tandem solar cells
Author(s) -
V. Sittinger,
Patricia S. C. Schulze,
Christoph Messmer,
Andreas Pflug,
Jan Christoph Goldschmidt
Publication year - 2022
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.458953
Subject(s) - refractive index , perovskite (structure) , materials science , silicon , ellipsometry , tandem , optics , optoelectronics , thin film , wavelength , chemistry , nanotechnology , crystallography , physics , composite material
Evaporated charge extraction layers from organic molecular materials are vital in perovskite-based solar cells. For opto-electronic device optimization their complex refractive indices must be known for the visible and near infrared wavelength regime; however, accurate determination from thin organic films below 50 nm can be challenging. By combining spectrophotometry, variable angle spectroscopic ellipsometry, and X-ray reflectivity with an algorithm that simultaneously fits all available spectra, the complex refractive index of evaporated Spiro-TTB and C 60 layers is determined with high accuracy. Based on that, an optical losses analysis for perovskite silicon solar cells shows that 15 nm of Spiro-TTB in the front of a n-i-p device reduces current by only 0.1 mA/cm 2 , compared to a substantial loss of 0.5 mA/cm 2 due to 15 nm of C 60 in a p-i-n device. Optical device simulation predicts high optical generation current densities of 19.7 and 20.1 mA/cm 2 for the fully-textured, module-integrated p-i-n and n-i-p devices, respectively.