التفاصيل البيبلوغرافية
| العنوان: |
Revealing the Importance of Energetic and Entropic Contributions to the Driving Force for Charge Photogeneration. |
| المؤلفون: |
Aplan MP, Munro JM, Lee Y, Brigeman AN, Grieco C, Wang Q, Giebink NC, Dabo I, Asbury JB, Gomez ED |
| المصدر: |
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2018 Nov 21; Vol. 10 (46), pp. 39933-39941. Date of Electronic Publication: 2018 Nov 08. |
| نوع المنشور: |
Journal Article |
| اللغة: |
English |
| بيانات الدورية: |
Publisher: American Chemical Society Country of Publication: United States NLM ID: 101504991 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1944-8252 (Electronic) Linking ISSN: 19448244 NLM ISO Abbreviation: ACS Appl Mater Interfaces Subsets: PubMed not MEDLINE |
| أسماء مطبوعة: |
Original Publication: Washington, D.C. : American Chemical Society |
| مستخلص: |
Despite significant recent progress, much about the mechanism for charge photogeneration in organic photovoltaics remains unknown. Here, we use conjugated block copolymers as model systems to examine the effects of energetic and entropic driving forces in organic donor-acceptor materials. The block copolymers are designed such that an electron donor block and an electron acceptor block are covalently linked, embedding a donor-acceptor interface within the molecular structure. This enables model studies in solution where processes occurring between one donor and one acceptor are examined. First, energy levels and dielectric constants that govern the driving force for charge transfer are systematically tuned and charge transfer within individual block copolymer chains is quantified. Results indicate that in isolated chains, a significant driving force of ∼0.3 eV is necessary to facilitate significant exciton dissociation to charge-transfer states. Next, block copolymers are cast into films, allowing for intermolecular interactions and charge delocalization over multiple chains. In the solid state, charge transfer is significantly enhanced relative to isolated block copolymer chains. Using Marcus Theory, we conclude that changes in the energetic driving force alone cannot explain the increased efficiency of exciton dissociation to charge-transfer states in the solid state. This implies that increasing the number of accessible states for charge transfer introduces an entropic driving force that can play an important role in the charge-generation mechanism of organic materials, particularly in systems where the excited state energy level is close to that of the charge-transfer state. |
| فهرسة مساهمة: |
Keywords: all-polymer solar cells; block copolymers; charge-transfer state; dielectric constant; exciton dissociation; nonfullerene acceptors; organic photovoltaics; quantum efficiency |
| تواريخ الأحداث: |
Date Created: 20181027 Date Completed: 20181126 Latest Revision: 20181126 |
| رمز التحديث: |
20221213 |
| DOI: |
10.1021/acsami.8b12077 |
| PMID: |
30360072 |
| قاعدة البيانات: |
MEDLINE |
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