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Title: Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction

Authors:
 [1];  [2];  [3];  [4];  [4];  [4];  [4]; ORCiD logo [5]; ORCiD logo [4]; ORCiD logo [4]
  1. National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Department of Physics, Colorado School of Mines, Golden, Colorado 80401, United States
  2. National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309, United States
  3. Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
  4. National Renewable Energy Laboratory, Golden, Colorado 80401, United States
  5. Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, United States; Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Advanced Solar Photophysics (CASP)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388278
DOE Contract Number:
AC52-06NA25396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nano Letters; Journal Volume: 17; Journal Issue: 2; Related Information: CASP partners with Los Alamos National Laboratory (lead); University of California, Irvine; University of Colorado; Colorado School of Mines; George Mason University; Los Alamos National Laboratory; University of Minnesota; National Renewable Energy Laboratory
Country of Publication:
United States
Language:
English
Subject:
solar (photovoltaic), solar (fuels), solid state lighting, bio-inspired, electrodes - solar, defects, charge transport, materials and chemistry by design, optics, synthesis (novel materials), synthesis (scalable processing)

Citation Formats

Crisp, Ryan W., Pach, Gregory F., Kurley, J. Matthew, France, Ryan M., Reese, Matthew O., Nanayakkara, Sanjini U., MacLeod, Bradley A., Talapin, Dmitri V., Beard, Matthew C., and Luther, Joseph M.. Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction. United States: N. p., 2017. Web. doi:10.1021/acs.nanolett.6b04423.
Crisp, Ryan W., Pach, Gregory F., Kurley, J. Matthew, France, Ryan M., Reese, Matthew O., Nanayakkara, Sanjini U., MacLeod, Bradley A., Talapin, Dmitri V., Beard, Matthew C., & Luther, Joseph M.. Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction. United States. doi:10.1021/acs.nanolett.6b04423.
Crisp, Ryan W., Pach, Gregory F., Kurley, J. Matthew, France, Ryan M., Reese, Matthew O., Nanayakkara, Sanjini U., MacLeod, Bradley A., Talapin, Dmitri V., Beard, Matthew C., and Luther, Joseph M.. Fri . "Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction". United States. doi:10.1021/acs.nanolett.6b04423.
@article{osti_1388278,
title = {Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction},
author = {Crisp, Ryan W. and Pach, Gregory F. and Kurley, J. Matthew and France, Ryan M. and Reese, Matthew O. and Nanayakkara, Sanjini U. and MacLeod, Bradley A. and Talapin, Dmitri V. and Beard, Matthew C. and Luther, Joseph M.},
abstractNote = {},
doi = {10.1021/acs.nanolett.6b04423},
journal = {Nano Letters},
number = 2,
volume = 17,
place = {United States},
year = {Fri Jan 13 00:00:00 EST 2017},
month = {Fri Jan 13 00:00:00 EST 2017}
}
  • Here, we developed a monolithic CdTe-PbS tandem solar cell architecture in which both the CdTe and PbS absorber layers are solution-processed from nanocrystal inks. Due to their tunable nature, PbS quantum dots (QDs), with a controllable band gap between 0.4 and ~1.6 eV, are a promising candidate for a bottom absorber layer in tandem photovoltaics. In the detailed balance limit, the ideal configuration of a CdTe (E g = 1.5 eV)-PbS tandem structure assumes infinite thickness of the absorber layers and requires the PbS band gap to be 0.75 eV to theoretically achieve a power conversion efficiency (PCE) of 45%.more » But, modeling shows that by allowing the thickness of the CdTe layer to vary, a tandem with efficiency over 40% is achievable using bottom cell band gaps ranging from 0.68 and 1.16 eV. In a first step toward developing this technology, we explore CdTe-PbS tandem devices by developing a ZnTe-ZnO tunnel junction, which appropriately combines the two subcells in series. Furthermore, we examine the basic characteristics of the solar cells as a function of layer thickness and bottom-cell band gap and demonstrate open-circuit voltages in excess of 1.1 V with matched short circuit current density of 10 mA/cm 2 in prototype devices.« less
  • Different approaches of surface modification of the quantum dots (QDs), namely, solution-phase (octylamine, octanethiol) and post-deposition (acetic acid, 1,4-benzenedithiol) ligand exchange were used in the fabrication of hybrid bulk heterojunction solar cell containing poly (3-hexylthiophene) (P3HT) and small (2.4 nm) PbS QDs. We show that replacing oleic acid by shorter chain ligands improves the figures of merit of the solar cells. This can possibly be attributed to a combination of a reduced thickness of the barrier for electron transfer and an optimized phase separation. The best results were obtained for post-deposition ligand exchange by 1,4-benzenedithiol, which improves the power conversion efficiencymore » of solar cells based on a bulk heterojunction of lead sulfide (PbS) QDs and P3HT up to two orders of magnitude over previously reported hybrid cells based on a bulk heterojunction of P3HT:PbS QDs, where the QDs are capped by acetic acid ligands. The optimal performance was obtained for solar cells with 69 wt. % PbS QDs. Besides the ligand effects, the improvement was attributed to the formation of an energetically favorable bulk heterojunction with P3HT, when small size (2.4 nm) PbS QDs were used. Dark current density-voltage (J-V) measurements carried out on the device provided insight into the working mechanism: the comparison between the dark J-V characteristics of the bench mark system P3HT:PCBM and the P3HT:PbS blends allows us to conclude that a larger leakage current and a more efficient recombination are the major factors responsible for the larger losses in the hybrid system.« less
  • We compared PbS quantum dot (QD) solar cells with different cathode interlayer materials, namely, LiF and ZnO nanoparticles, using the same device structure. Solar cells fabricated with the ZnO interlayer gave a power conversion efficiency of 4.8%, which is higher (above the experimental variation) than the 4.1% efficiency obtained with a LiF interlayer. We found that the ZnO interlayer alters the spatial distribution of the optical field, leading to an increase in external quantum efficiency in the visible range. Furthermore, devices with ZnO as interlayer showed more stable performance than the ones using LiF, with practically no power conversion efficiencymore » degradation after 1 month inside a N{sub 2} glovebox.« less
  • The results of the analysis of the infrared lattice reflectance spectra of multiperiod ZnTe/CdTe superlattices with CdTe quantum dots are reported. The samples are grown by molecular beam epitaxy on the GaAs substrate with the ZnTe buffer layer. Due to the large number of periods of the superlattices, it is possible to observe CdTe-like vibration modes in the quantum dots, i.e., the dislocation-free stressed islands formed during the growth due to relaxation of elastic stresses between the ZnTe and CdTe layers are markedly different in their lattice parameters. From the frequency shifts of the CdTe- and ZnTe-like vibration modes withmore » respect to the corresponding modes in the unstressed materials, it is possible to estimate the level of elastic stresses.« less