Contrastive analysis of multiple exciton generation theories

Hengyu Tan; Qing Chang

doi:10.1117/12.2199053

15 October 2015 Contrastive analysis of multiple exciton generation theories

Hengyu Tan, Qing Chang

Proceedings Volume 9671, AOPC 2015: Advances in Laser Technology and Applications; 96710I (2015) https://doi.org/10.1117/12.2199053
Event: Applied Optics and Photonics China (AOPC2015), 2015, Beijing, China

Abstract

Multiple exciton generation (MEG) is an effect that semiconductor nanocrystals (NCs) quantum dots (QDs) generate multiple excitons (electron-hole pairs) through absorbing a single high energy photon. It can translate the excess photon energy of bandgap (E_g) into new excitons instead of heat loss and improve the photovoltaic performance of solar cells. However, the theories of MEG are not uniform. The main MEG theories can be divided into three types. The first is impact ionization. It explains MEG through a conventional way that a photogenerated exciton becomes multiple excitons by Coulomb interactions between carriers. The Second is coherent superposition of excitonic states. Multiple excitons are generated by the coherent superposition of single photogenerated exciton state with enough excess momentum and the two-exciton state with the same momentum. The third is excitation via virtual excitonic states. The nanocrystals vacuum generates a virtual biexciton by coulomb coupling between two valence band electrons. The virtual biexciton absorbing a photon with an intraband optical transition is converted into a real biexciton. This paper describes the MEG influence on solar photoelectric conversion efficiency, concludes and analyzes the fundamentals of different MEG theories, the MEG experimental measure, their merits and demerits, calculation methods of generation efficiency.

Citation Download Citation

Hengyu Tan and Qing Chang "Contrastive analysis of multiple exciton generation theories", Proc. SPIE 9671, AOPC 2015: Advances in Laser Technology and Applications, 96710I (15 October 2015); https://doi.org/10.1117/12.2199053

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
6 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Excitons

Magnetoencephalography

Solar energy

Electrons

Solar cells

Semiconductors

Absorption

Show All Keywords

Keywords/Phrases

Search In:

Publication Years