Ultrathin and Efficient Organic Photovoltaics with Enhanced Air Stability by Suppression of Zinc Element Diffusion

Abstract

Ultrathin (thickness less than 10 μm) organic photovoltaics (OPVs) can be applied to power soft robotics and wearable electronics. In addition to high power conversion efficiency, stability under various environmental stresses is crucial for the application of ultrathin OPVs. In this study, the authors realize highly air-stable and ultrathin (≈3 μm) OPVs that possess high efficiency (15.8%) and an outstanding power-per-weight ratio of 33.8 W g −1 . Dynamic secondary-ion mass spectrometry is used to identify Zn diffusion from the electron transport layer zinc oxide (ZnO) to the interface of photoactive layer; this diffusion results in the degradation of the ultrathin OPVs in air. The suppression of the Zn diffusion by a chelating strategy results in stable ultrathin OPVs that maintain 89.6% of their initial efficiency after storage for 1574 h in air at room temperature under dark conditions and 92.4% of their initial efficiency after annealing for 172 h at 85 °C in air under dark conditions. The lightweight and stable OPVs also possess excellent deformability with 87.3% retention of the initial performance after 5000 cycles of a compressing-stretching test with 33% compression.

Effect of Wetting Surfactants on the Work Function of PEDOT:PSS for Organic Solar Cells

“…PEI-Zn is zinc ion-chelated polyethylenimine, an electron-transporting layer . It shows superiority in terms of mechanical flexibility and device stability compared with the traditional ZnO. Current density–voltage ( J–V ) curves are presented in Figure b.…”

Ultrathin Hydrogel Films toward Breathable Skin‐Integrated Electronics

“…The photovoltaics were based on a well-known organic blend of PM6:Y6 [61] fabricated on the ultrathin parylene substrate (depicted in the Experimental Section). [62,63] As detailed in Figure 5F and Figure S11B-D (Supporting Information), photovoltaics treated with low power (10 W) O 2 plasma for 60 s or higher power (40-200 W) O 2 plasma for a short duration time (e.g., 10 s) do not show visible performance deterioration. O 2 plasma treatment with high power and a long duration time (40 W for 60 s) accelerates the deterioration of the photovoltaics, as detailed in Figure S11E (Supporting Information).…”

Integration of body-mounted ultrasoft organic solar cell on cyborg insects with intact mobility

“…Both modules on flat and on 3D model show similar operation stability under the maximum power point tracking (MPPT) of simulated sun-light, displaying the reasonable stability on curved surfaces. The faster degradation of the large area modules than small-area single cell is attributed from leakage current path of the larger effective area 28 .…”

“…The ITO electrode was patterned by photolithography, and 3.5 nm-thick Cr and 100 nm-thick Au layers were deposited onto the ITO electrode as supporting wires. PEIE chelated with Zn 2+ (PEI-Zn) was used as the electron transport layer 28,37 . The PEI-Zn precursor solution was prepared by dissolving 70 mg of zinc acetate dihydrate in 1 wt% PEIE 2-methoxyethanol.…”

“…Emergent solar cells, including organic 25 , perovskite 26 , and quantum dot cells 27 , can achieve high power per weight because of their reduced substrate and passivation thicknesses, which is beneficial for achieving integration in living small insects. Ultrathin organic solar cells having a total thickness of less than 5 μm can achieve a power conversion efficiency (PCE) of 15.8% resulting in a power per weight of 33.8 W g -1 28 .…”