Nanoscale imaging and spectroscopy of band gap and defects in polycrystalline photovoltaic devices

Improving the power conversion efficiency of photovoltaic (PV) devices is challenging because the generation, separation and collection of electron-hole pairs are strongly dependent on details of the nanoscale chemical composition and defects which are often poorly known. In this work, two novel sca...

Full description

Saved in:
Bibliographic Details
Published in:Nanoscale 2017-06, Vol.9 (23), p.7771-7780
Main Authors: Yoon, Yohan, Chae, Jungseok, Katzenmeyer, Aaron M, Yoon, Heayoung P, Schumacher, Joshua, An, Sangmin, Centrone, Andrea, Zhitenev, Nikolai
Format: Article
Language:English
Subjects:
Crystal defects
Devices
Energy gaps (solid state)
Grains
Nanostructure
Photovoltaic cells
Solar cells
Spectra
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Improving the power conversion efficiency of photovoltaic (PV) devices is challenging because the generation, separation and collection of electron-hole pairs are strongly dependent on details of the nanoscale chemical composition and defects which are often poorly known. In this work, two novel scanning probe nano-spectroscopy techniques, direct-transmission near-field scanning optical microscopy (dt-NSOM) and photothermal induced resonance (PTIR), are implemented to probe the distribution of defects and the bandgap variation in thin lamellae extracted from polycrystalline CdTe PV devices. dt-NSOM provides high-contrast spatially-resolved maps of light transmitted through the sample at selected wavelengths. PTIR provides absorption maps and spectra over a broad spectral range, from visible to mid-infrared. Results show variation of the bandgap through the CdTe thickness and from grain to grain that is spatially uncorrelated with the distributions of shallow and deep defects.
ISSN:2040-3364
2040-3372
DOI:10.1039/c7nr01480e