Highly efficient organic photovoltaics with enhanced stability through the formation of doping-induced stable interfaces

Abstract

Flexible organic photovoltaics (OPVs) are promising power sources for wearable electronics. However, it is challenging to simultaneously achieve high efficiency as well as good stability under various stresses. Herein, we demonstrate the fabrication of highly efficient (efficiency, 13.2%) and stable OPVs based on nonfullerene blends by a single-step postannealing treatment. The device performance decreases dramatically after annealing at 90 °C and is fully recovered after annealing at 150 °C. Glass-encapsulated annealed OPVs show good environmental stability with 4.8% loss in efficiency after 4,736 h and an estimatedT80lifetime (80% of the initial power conversion efficiency) of over 20,750 h in the dark under ambient condition andT80lifetime of 1,050 h at 85 °C and 30% relative humidity. This environmental stability is enabled by the synergetic effect of the stable morphology of donor/acceptor blends and thermally stabilized interfaces due to doping. Furthermore, the high efficiency and good stability are almost 100% retained in ultraflexible OPVs and minimodules which are mechanically robust and have long-term operation capability and thus are promising for future self-powered and wearable electronics.

An Alternative Approach to Simulate the Power Conversion Efficiency of Bulk Heterojunction Organic Solar Cells

“…[ 4 ] In addition to the enhancement in PCE, an improvement in stability has also been achieved in OSCs fabricated recently with a shelf lifetime of up to 11.4 years. [ 10 ] The lower PCE and instability are the two key limitations for BHJ OSCs in reaching commercialization.…”

Molecular Design of Efficient Chlorine‐ and Carboxylate‐Functionalized Donor Polymers for Nonfullerene Organic Solar Cells Enabling Processing with Eco‐Friendly Solvent in Air

“…[ 42 ] Subsequently, the PCEs remain relatively steady up to 100 h. In short, both devices maintained PCEs of over 63% of their initial values for 100 h, suggesting reasonable photostability of the photoactive materials and NFOSC devices. [ 23,25,35-37,66,67 ]…”

Ultraflexible Integrated Organic Electronics for Ultrasensitive Photodetection

“…A PBDTTT‐OFT:IEICO‐4F [ 28 ] solution (25 mg mL −1 ) was prepared by blending 15 mg of PBDTTT‐OFT (Toray Industries) and 10 mg of IEICO‐4F (1‐Material) in a 0.97 mL solution of chlorobenzene (C 6 H 5 Cl, Wako) and 0.03 mL of 1‐chloronaphthalene additive (Sigma‐Aldrich). A ZnO precursor solution was prepared by dissolving zinc acetate dehydrate (0.55 g, Wako Chemicals) and ethanolamine (0.16 mL, Wako Chemicals) in 5 mL of 2‐methoxyethanol (Wako Chemicals).…”

“…The OPD module was fabricated using a process similar to that reported previously. [ 28 ] Bare glass substrates were treated with O 2 plasma for 10 min at 300 W power, and then coated with a fluoropolymer by spin‐coating the polymer solution (Novec 1702/7200, 3 M company) at 5000 rpm for 60 s. They were then coated with an ≈1 µm thick layer of transparent polyimide (ECRIOS; Mitsui Chemicals). The polyimide layer was cured into a film by annealing at 270 °C for 2 h in a N 2 atmosphere.…”

“…For the light detection component of our photodetector, we developed an inverted‐structure OPD module based on a BHJ composed of a mixture of a poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(4‐octyl‐3‐fluorothieno[3,4‐b]thiophene)‐2‐carboxylate‐2–6‐diyl] (PBDTTT‐OFT) polymeric donor and an IEICO‐4F small molecule acceptor, which also shows good environmental stability. [ 27,28 ] A single‐cell OPD exhibited high photovoltaic performance, including a short‐circuit current density ( J SC ) of 25.52 mA cm −2 , an open‐circuit voltage ( V OC ) of 0.70 V, and a fill factor (FF) of 0.73, resulting in a high power‐conversion efficiency (PCE) of 13.0% (Table S1, Supporting Information). For a desired application, the output performance of the OPD can be further modulated by designing an OPD module that connects two or more OPDs.…”