《Nature Photonics(IF>39.728)》A Research Team Led by Huanping Zhou of Peking University Proposed that the Starch-Polyiodide Supermolecule Buffer Layer Enhances the Fatigue Resistance of Perovskite Solar Cells with 24.3% Efficiency
- The research team led by Huanping Zhou utilized a starch-polyiodide supermolecule as a buffer layer to significantly improve the fatigue behavior and cycling stability of perovskite solar cells.
- The modified perovskite solar cells maintained 98% of their power conversion efficiency after 42 consecutive day-night cycles.
- The study provides important insights into utilizing supramolecular chemistry to modulate the metastable dynamics of soft crystalline materials.
Perovskite solar cells are highly sensitive to external stimuli due to their soft and ionic crystal lattice structure. They tend to exhibit noticeable fatigue under cyclic loading in real-world environments. The lack of fundamental understanding of materials degradation has resulted in ineffective solutions to alleviate such fatigue under cyclic illumination.
The researchers introduced a starch-polyiodide supermolecule as a bifunctional buffer layer at the perovskite interface, which can both inhibit ion migration and promote defect self-healing. The modified perovskite solar cells retained 98% of their original power conversion efficiency after 42 day-night cycles. They also achieved a 24.3% power conversion efficiency (certified 23.9%) and intense electroluminescence with external quantum efficiencies above 12%.
The researchers first synthesized the starch-polyiodide supermolecule material and incorporated it as a buffer layer between the transport layer and the perovskite light absorber. They analyzed the effects of the buffer layer from multiple angles, including electrochemical measurements, photoluminescence spectra, grazing-incidence X-ray diffraction, thermogravimetric analysis, etc., to confirm its bifunctional mechanism. Perovskite solar cells with the buffer layer were then prepared and subjected to 42 day-night cycles of accelerated aging tests to evaluate their cycling stability and power output. The results validated that the buffer layer significantly enhanced the durability of the cells under cyclic loading.
This study significantly enhanced the cycling stability and fatigue behavior of perovskite solar cells by introducing a starch-polyiodide supermolecule buffer layer interface. It provides an effective approach to enable practical applications of perovskite solar cells. The bifunctional mechanism of the supermolecular buffer layer could also be applied to interface design of other soft crystalline materials. The findings provide important insights into utilizing supramolecular chemistry to modulate the metastability of soft crystalline materials.
Fig. S28. a, J-V curves of w/ Starch-I devices with different Starch-I concentrations. b,
Dependence of VOC and FF with Starch-I concentration. c, EQE of EL of the devices
while operating as LEDs. d, Dependence of EQEEL and VOC with Starch-I concentration.
Fig. S30. The J-V curve of the w/ Starch-I device (a) and reference (b).
Fig. S32. External quantum efficiency (EQE) spectra together with the integrated JSC
of 24.5 mA cm-2 457 for the w/ Starch-I device.
Fig. S34. The J-V curves (from 1.2 V to –0.2 V at 67 mV s1 470 ) of the devices before and
after 1472 h SPO tracking. The PCE of the reference device decreased from 20.1% to
14.0% after aging, while the Starch-I device decreased from 20.5% to 19.4%.
Fig. S36. The J-V curves (from 1.2 V to –0.2 V at 67 mV s1 483 ) of the devices before and
after DCO (12/12 h light/dark cycle, 1008 hours in total) tracking. The PCE of the reference device decreased from 20.7 % to 11.6% after aging, while the Starch-I device decreased from 21.6% to 21.2%.
Fig. S39. The J-V curves of the devices before and after DCO (20 mins per cycle)
tracking. The PCE of the Starch-I device decreased from 21.5% to 20.7%.