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Strong photocurrent from 2D excitons in solution-processed stacked perovskite semiconductor sheets


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Authors

Ahmad, Shahab 
Kanaujia, Pawan Kumar 
Beeson, Harry J. 
Abate, Antonio 
Deschler, Felix 

Abstract

Room-temperature photocurrent measurements in two-dimensional inorganic-organic perovskite devices reveal that excitons strongly contribute to the photocurrents despite possessing binding energies over ten times larger than thermal energies. The p-type (C₆H₉C₂H4NH₃)₂PbI₄ [CHPI] liberates photocarriers at metallic Schottky Al contacts, but incorporating electron and hole transport layers enhances the extracted photo-currents by a hundred-fold. A further ten-fold gain is found when integrating TiO₂ nanoparticles directly into the perovskite layers, although the 2D excitons semic onducting layers are not significantly disrupted. These results show that strong excitonic materials may be useful as photovoltaic materials despite high exciton binding energies, and suggest mechanisms to better understand photovoltaic properties of the related 3D perovskites.

Description

This is the final version of the article. It was first available from ACS via http://dx.doi.org/10.1021/acsami.5b07026

Keywords

inorganic-organic hybrid, layered perovskite, room-temperature exciton, exciton photocurrent, photodetector

Journal Title

ACS Applied Materials & Interfaces

Conference Name

Journal ISSN

Volume Title

7

Publisher

ACS
Sponsorship
This work is part of High-Impact Research scheme of IIT Delhi, DST project (Govt. Of India), DST-FIST (Govt. of India) and UK-India Education and Research Initiative (UKIERI) programmes. This work was supported by EPSRC grants EP/K028510/1, EP/G060649/1, EP/G037221/1, EP/H007024/1, EP/L015978/1, the Cambridge NanoDTC, and ERC LINASS 320503.