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Ultimate Charge Extraction of Monolayer PbS Quantum Dot for Observation of Multiple Exciton Generation |
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| Authors: | Dr So-Yeon Park Sehoon Han Dr Younghoon Kim Prof Sohee Jung Prof Dong Hoe Kim Dr Gill Sang Han Prof Hyun Suk Jung |
| Institution: | 1. School of Advanced Materials & Engineering, Sungkyunkwan University, Suwon, 16419 Republic of Korea
These authors contributed equally to this work;2. Convergence Research Center for Solar Energy Convergence Research Institute, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, 72988 Republic of Korea;3. Department of Energy Science, Sungkyunkwan University, Suwon, 16419 Republic of Korea;4. Department of Nanotechnology & Advanced Materials Engineering Sejong University, Seoul, 05006 Republic of Korea;5. School of Advanced Materials & Engineering, Sungkyunkwan University, Suwon, 16419 Republic of Korea |
| Abstract: | 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 Jsc (Jsc∝Iα) 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 (Eg), 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. |
| Keywords: | colloid quantum dot solar cell fast charge extraction Langmuir–Blodgett monolayer PbS multiple exciton generation |