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Direct correlation of nanoscale morphology and device performance to study photocurrent generation in donor enriched phases of polymer solar cells
Direct correlation of nanoscale morphology and device performance to study photocurrent generation in donor enriched phases of polymer solar cells
- Source :
- ACS Applied Materials & Interfaces, ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2020, ⟨10.1021/acsami.0c05884⟩, ACS Applied Materials & Interfaces, 2020, ⟨10.1021/acsami.0c05884⟩, ACS applied materials & interfaces, 12 (2020): 28404–28415. doi:10.1021/acsami.0c05884, info:cnr-pdr/source/autori:Ben Dkhil, Sadok; Perkhun, Pavlo; Luo, Chieh; Mueller, David; Alkarsifi, Riva; Barulina, Elena; Quiroz, Yatzil Alejandra Avalos; Margeat, Olivier; Dubas, Stephan Thierry; Koganezawa, Tomoyuki; Kuzuhara, Daiki; Yoshimoto, Noriyuki; Caddeo, Claudia; Mattoni, Alessandro; Zimmermann, Birger; Wuerfel, Uli; Pfannmoeller, Martin; Bals, Sara; Ackermann, Joerg; Videlot-Ackermann, Christine/titolo:Direct Correlation of Nanoscale Morphology and Device Performance to Study Photocurrent Generation in Donor-Enriched Phases of Polymer Solar Cells/doi:10.1021%2Facsami.0c05884/rivista:ACS applied materials & interfaces (Print)/anno:2020/pagina_da:28404/pagina_a:28415/intervallo_pagine:28404–28415/volume:12, ACS applied materials and interfaces
- Publication Year :
- 2020
-
Abstract
- The nanoscale morphology of polymer blends is a key parameter to reach high efficiency in bulk heterojunction solar cells. Thereby, research typically focusing on optimal blend morphologies while studying nonoptimized blends may give insight into blend designs that can prove more robust against morphology defects. Here, we focus on the direct correlation of morphology and device performance of thieno[3,4-b]-thiophene-alt-benzodithiophene (PTB7):[6,6]phenyl C-71 butyric acid methyl ester (PC71BM) bulk heterojunction (BHJ) blends processed without additives in different donor/acceptor weight ratios. We show that while blends of a 1:1.5 ratio are composed of large donor-enriched and fullerene domains beyond the exciton diffusion length, reducing the ratio below 1:0.5 leads to blends composed purely of polymer-enriched domains. Importantly, the photocurrent density in such blends can reach values between 45 and 60% of those reached for fully optimized blends using additives. We provide here direct visual evidence that fullerenes in the donor-enriched domains are not distributed homogeneously but fluctuate locally. To this end, we performed compositional nanoscale morphology analysis of the blend using spectroscopic imaging of low-energy-loss electrons using a transmission electron microscope. Charge transport measurement in combination with molecular dynamics simulations shows that the fullerene substructures inside the polymer phase generate efficient electron transport in the polymer-enriched phase. Furthermore, we show that the formation of densely packed regions of fullerene inside the polymer phase is driven by the PTB7:PC71BM enthalpy of mixing. The occurrence of such a nanoscale network of fullerene clusters leads to a reduction of electron trap states and thus efficient extraction of photocurrent inside the polymer domain. Suitable tuning of the polymer-acceptor interaction can thus introduce acceptor subnetworks in polymer-enriched phases, improving the tolerance for high-efficiency BHJ toward morphological defects such as donor-enriched domains exceeding the exciton diffusion length.
- Subjects :
- additive
Fullerene
Materials science
02 engineering and technology
010402 general chemistry
01 natural sciences
Polymer solar cell
law.invention
PTB7:PC71BM
law
Solar cell
General Materials Science
ComputingMilieux_MISCELLANEOUS
Photocurrent
business.industry
Physics
[CHIM.MATE]Chemical Sciences/Material chemistry
021001 nanoscience & nanotechnology
Nanoscale morphology
blend ratio
0104 chemical sciences
charge transport
solar cell
[CHIM.POLY]Chemical Sciences/Polymers
Transmission electron microscopy
Photovoltaik
Optoelectronics
nanoscale fullerene network
Polymer blend
Neuartige Photovoltaik-Technologien
0210 nano-technology
business
Engineering sciences. Technology
Subjects
Details
- ISSN :
- 19448244 and 19448252
- Database :
- OpenAIRE
- Journal :
- ACS Applied Materials & Interfaces
- Accession number :
- edsair.doi.dedup.....ce757bf5862243f0e4ba98b55e3a1b74
- Full Text :
- https://doi.org/10.1021/acsami.0c05884