Shanghai Jiao Tong University’s Liu Feng: AM = 17.6% at 18.4 cm²! Organic solar cells fabricated using low-toxicity solvents!
Release Date:
2025-05-02 10:17
Source:
Organic photovoltaic (OPV) devices aim to harness solar energy in an environmentally friendly, highly efficient, and low-cost manner, thereby offering a sustainable solution for both energy production and ecological conservation.
Based on this, Liu Feng and others from Shanghai Jiao Tong University We are committed to optimizing the engineering fabrication techniques for organic photovoltaic devices and microcomponents by developing low-environmental-impact solvent-based processing methods. A newly developed solvent-engineering strategy employs the environmentally friendly o-xylene (OXY) along with a synergistic dual additive system (DIM and DIB), achieving optimal power conversion efficiency ( PCE) 20.0% (J SC To 26.6 mA cm ⁻ 2 , V OC with a PCE of 0.935 V and a fill factor of 80.3%, while also demonstrating excellent stability (retaining 82% of initial performance after 1,500 hours). The mini-modules treated with an optimized TCE:OXY solvent (volume ratio of 1:3) exhibit scalable performance, achieving an efficiency of 17.6% over an active area of 18.4 cm². This represents the highest performance achieved to date in the development of organic photovoltaic devices based on safe solvents. The paper was recently published in a journal under the title “Lowering toxicity of solvent in organic solar cells manufacturing for 20% efficiency.” Advanced Materials Up.
Figure 5. Wide-angle light utilization and large-area modules. a) J–V curves of the reference device and the DIM&DIB-treated device as a function of the light-incidence angle. (Dashed lines represent the reference; solid lines represent the DIM&DIB treatment.) b) PCE variations of the reference device and the DIM&DIB-treated device at different light-incidence angles. (Blue bars represent the reference; red bars represent the DIM&DIB treatment.) c) J–V curves of a large-area (18.4 cm²) PM6:PY-IT:L8-BO ternary solar module, along with front- and back-side photographs of the module. d) Plot showing the relationship between PCE and FF for high-efficiency large-area modules reported in the literature. Detailed data based on 11 data points from 10 publications are provided in Table S20 (Supporting Information). PL mapping of bulk-heterojunction (BHJ) films prepared using the following precursor solvents: e) TCE; f) TCE:OXY (volume ratio 1:3).
In summary, the use of hazardous solvents during OPV fabrication has raised concerns about ecological impacts and biodiversity. To address this issue, the authors selected the environmentally friendly solvent o-xylene (OXY) as the precursor solution. By integrating a synergistic additive strategy to optimize morphology and reduce energy losses, Devices treated with OXY achieved a power conversion efficiency (PCE) of 20.0%. Importantly, these results demonstrate that OPV devices fabricated using safe solvents exhibit comparable performance under both nitrogen and ambient air conditions, thereby enhancing the feasibility of large-scale production. Consequently, OPV modules manufactured via an environmentally friendly approach attained a PCE of 17.6% on an active area of 18.4 cm². Furthermore, the active-layer composition comprising a polymer donor and a polymeric non-fullerene acceptor (NFA) exhibits intrinsic structural stability, which helps to extend the operational lifetime of OPV devices and enhance their thermal stability. Meanwhile, the incorporation of L8-BO renders the active layer particularly well-suited for OXY treatment. The introduction of the solid additive DIB, however, leads to mechanical instability, thereby giving rise to micron-scale optical patterns that favor wide-angle light harvesting. These characteristics are crucial for integrating OPVs into urban environments, offering a new engineering-optimized perspective for developing long-term solutions to environmental challenges.
Device Fabrication
Device fabrication:
ITO/2PACz/BHJ/PNDIT-F3N/Ag
1. Wash the ITO glass thoroughly, then treat it with ozone for 20 minutes at a concentration of 0.3 mg/mL of 2PACz in ethanol; spin-coat at 3000 rpm, followed by annealing at 100°C for 6 minutes; finally, rinse the substrate with ethanol at 4000 rpm.
2. PM6:L8-BO, PM6:PY-IT, PM6:PY-IT:L8-BO = 1:1.2, 1:1.2: 1:0.8:0.4 (w/w); the loadings of DIM, DIB, and DIM&DIB in the ternary BHJ are 0.8% vol, 25 mg mL, respectively. -1 , 0.3% vol and 21 mg/mL -1 , donor concentration 7 mg/mL -1 (or 13 mg/mL in CF) -1 (Within OXY) Spin-coat at 2800 rpm for 40 seconds, then anneal at 100°C for 10 minutes, using CS. 2 Perform SVA treatment using a solvent;
3. Spin-coat at 2600 rpm for 30 seconds using a PNDIT-F3N solution in MeOH containing 0.3% glacial acetic acid at a concentration of 0.7 mg/mL;
4. Evaporate 120 nm of Ag.
Module:
ITO/PEDOT:PSS/active layer/PNDIT-F3N/Ag
1. Wash the ITO-coated glass thoroughly, then perform P1 scribing using a 1064 nm laser at a power of 3 W, with a scribing width of 25 µm; subsequently spin-coat a 15 nm layer of PEDOT:PSS and anneal at 150°C for 20 minutes.
2. Bulk concentration: 10 mg/mL PM6:PY-IT:L8-BO = 1:0.8:0.4 w/w + 0.1% DIM + 7 mg/mL -1 DIB is dissolved in TCE:OXY (1:3 v/v), spin-coated, and annealed at 100°C for 10 minutes, N 2 SVA CS in the glove box 2 60s;
3. Spin-coat at 2600 rpm for 30 seconds using a PNDIT-F3N solution in MeOH containing 0.3% glacial acetic acid at a concentration of 0.7 mg/mL;
4. 532 nm nanosecond laser P2 scribing (power: 2 W, scribing width: 75 µm, spacing from P1 scribing: 50 µm);
5. Evaporate 150 nm of Ag;
6. P3 scribing (width: 400 µm, spacing from P2 scribing: 150 µm), GFF: 90.37%.
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