Organic photovoltaic mini-modules fabricated with simple nozzle-printing process

Abstract

Organic photovoltaic (OPV) devices have been widely studied as a renewable energy and next-generation self-power generator that can convert solar energy to green electrical energy. It has many advantages such as low production cost, light weight, flexibility, and large-scale fabrication. The printing technique has many advantages such as reducing material waste, environmental-friendly process, non-contact method, fast printing speed, and fine-pattern compared to typical spin-coating or doctor-blade coating. In this research, we have introduced an air pulse nozzle-printing (Musashi Engineering, Image Master 350 PC) technique that easy fabricate photoactive layer with high-resolution as well as freedom design. The properties of nozzle-printed OPV cells and mini-modules have investigated as a function of the printing conditions. For preparation printable ink, the photoactive materials with poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) (P3HT:PCBM, 10 mg/ml) mixed solution have dissolved and measured the shear viscosity and dynamic surface tension properties. The surface tension values of active material has not much changed in the range of 0.03 to 20 s and then converges to approximately 31 mN/m. The shear viscosity profile showed shear-thinning behavior, which is time-independent non-Newtonian fluid. It has characterized by a decrease in viscosity over an increasing shear rate, over the 10-1 to 103 s-1 shear rate range, which resulted in a suitable values enough to printing process. Parallel-connected OPV mini-modules from 1 cell to 4 cells could be generated the current about 1.28, 2.35, 3.47, and 4.58 mA at 0.04 cm2 active area. It was possible to produce a high current over 40 mA at 4.8 cm2 active area that manufacture the high-efficiency mini-modules by reducing the dead-space and expanding the active area as well as improving of the photoactive material properties. This research was supported by Korea Electric Power Corporation(Grant Number: R18XA06-11) and partially supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea(20193020010370).