Scalable organic photovoltaic devices with a stable power conversion efficiency of = 13% suitable for flexible substrates

Objective of the proposed work is the demonstration of scalable organic photovoltaic (OPV) devices with power conversion efficiencies of = 13% suitable for flexible light-weight substrates. Particular attention will be paid to stability, limiting performance loss to less than 10% to break-in over 100 hours unpackaged and 1000 hours packaged. Fabrication of such devices on flexible substrates is expected to meet the Navy’s needs for energy austerity in future Expeditionary Advanced Base Operations (EABO). The technical effort will focus on the utilization of existing state-of-the-art materials enabling the required performance levels and their implementation in industrially pertinent device architectures suitable for rapid scale-up. PffBT4T-2OD (also known as PCE11), PffBT4T-2DT and PTQ10 will be used as electron-donating polymers and their performance in combination with fullerene derivatives and the non-fullerene acceptors IDT2BR, ITIC, ITIC-2F, ITIC-4F, IDIC and EH-IDTBR investigated. For initial screening, ITO/ZnO/active layer/PEDOT:PSS/Ag devices will be prepared at both UML and Nano-C. The polymer-acceptor ratio will be kept steady at 1:1.5 whereas NFA abundances of 10, 25 and 50% will be investigated. The four most promising materials systems will be selected and the composition as well as solvents systems, used for deposition, further refined. The replacement of [60]PCBM by Nano-C’s new generation fullerene-based acceptor materials, enabling improved stability, will be investigated and the effect of stabilizing as well as performance enhancing additive assessed. Larger, 1 cm2, devices will be fabricated and connected in series resulting in first modules. Devices will be encapsulated and subjected to light soaking. 2 – 3 unpackaged as well as 2 – 3 packaged devices will be fabricated for evaluation by a third-party suggested by the Navy. A final report will be prepared including a detailed description of the best suitable path to the fabrication of packaged 50 cm2 modules on flexible (probably PET) substrates. A cost analysis based on the materials identified to be best suitable will be conducted. Industrially pertinent roll-to-roll (R2R) and sheet-to-sheet (S2S) device fabrication methods will be explored during the Phase I option. The fabrication of fully spray coated devices will be demonstrated by Nano-C.