| 1. |
- Lin, Yuanbao, et al.
(författare)
-
One-Step Blade-Coated Highly Efficient Nonfullerene Organic Solar Cells with a Self-Assembled Interfacial Layer Enabled by Solvent Vapor Annealing
- 2019
-
Ingår i: Solar RRL. - : Wiley. - 2367-198X. ; 3:8
-
Tidskriftsartikel (refereegranskat)abstract
- A pronounced enhancement of the power conversion efficiency (PCE) by 38% is achieved in one-step doctor-blade printing organic solar cells (OSCs) via a simple solvent vapor annealing (SVA) step. The organic blend composed of a donor polymer, a nonfullerene acceptor, and an interfacial layer (IL) molecular component is found to phase-separate vertically when exposed to a solvent vapor-saturated atmosphere. Remarkably, the spontaneous formation of a fine, self-organized IL between the bulk heterojunction (BHJ) layer and the indium tin oxide (ITO) electrode facilitated by SVA yields solar cells with a significantly higher PCE (11.14%) than in control devices (8.05%) without SVA and in devices (10.06%) made with the more complex two-step doctor-blade printing method. The stratified nature of the ITO/IL/BHJ/cathode is corroborated by a range of complementary characterization techniques including surface energy, cross-sectional scanning electron microscopy, grazing incidence wide angle X-ray scattering, and X-ray photoelectron spectroscopy. This study demonstrates that a spontaneously formed IL with SVA treatment combines simplicity and precision with high device performance, thus making it attractive for large-area manufacturing of next-generation OSCs.
|
|
| 2. |
- Ma, Z. F., et al.
(författare)
-
Structure-Property Relationships of Oligothiophene-Isoindigo Polymers for Efficient Bulk-Heterojunction Solar Cells
- 2014
-
Ingår i: Energy and Environmental Sciences. - 1754-5692 .- 1754-5706. ; 7:1, s. 361-369
-
Tidskriftsartikel (refereegranskat)abstract
- A series of alternating oligothiophene (nT)–isoindigo (I) copolymers (PnTI) were synthesized to investigate the influence of the oligothiophene block length on the photovoltaic (PV) properties of PnTI:PCBM bulk-heterojunction blends. Our study indicates that the number of thiophene rings (n) in the repeating unit alters both polymer crystallinity and polymer–fullerene interfacial energetics, which results in a decreasing open-circuit voltage (Voc) of the solar cells with increasing n. The short-circuit current density (Jsc) of P1TI:PCBM devices is limited by the absence of a significant driving force for electron transfer. Instead, blends based on P5TI and P6TI feature large polymer domains, which limit charge generation and thus Jsc. The best PV performance with a power conversion efficiency of up to 6.9% was achieved with devices based on P3TI, where a combination of a favorable morphology and an optimal interfacial energy level offset ensures efficient exciton separation and charge generation. The structure–property relationship demonstrated in this work would be a valuable guideline for the design of high performance polymers with small energy losses during the charge generation process, allowing for the fabrication of efficient solar cells that combine a minimal loss in Voc with a high Jsc.
|
|
