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Ultimate Charge Extraction of Monolayer PbS Quantum Dot for Observation of Multiple Exciton Generation
Author(s) -
Park SoYeon,
Han Sehoon,
Kim Younghoon,
Jung Sohee,
Kim Dong Hoe,
Han Gill Sang,
Jung Hyun Suk
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900381
Subject(s) - quantum dot , monolayer , multiple exciton generation , optoelectronics , exciton , quantum dot solar cell , materials science , charge carrier , band gap , photovoltaic system , quantum efficiency , energy conversion efficiency , nanotechnology , polymer solar cell , physics , condensed matter physics , ecology , biology
Multiple exciton generation (MEG) has great potential to improve the Shockley‐Queisser (S‐Q) efficiency limitation for colloidal quantum dot (CQD) solar cells. However, MEG has rarely been observed in CQD solar cells because of the loss of carriers through the transport mechanism between adjacent QDs. Herein, we demonstrate that excess charge carriers produced via MEG can be efficiently extracted using monolayer PbS QDs. The monolayer PbS QDs solar cells exhibit α =1 in the light intensity dependence of the short‐circuit current density J sc ( J sc ∝ I α ) and an internal quantum efficiency (IQE) value of 100 % at 2.95 eV because of their very short charge extraction path. In addition, the measured MEG threshold is 2.23 times the bandgap energy ( E g ), which is the lowest value in PbS QD solar cells. We believe that this approach can provide a simple method to find suitable CQD materials and design interface engineering for MEG.