Integrated organic photovoltaic modules

摘要

Methods for scalable output voltage and encapsulation of organic photovoltaic cells are addressed in this paper. To obtain scalable output voltages, integrated photovoltaic modules comprised of a bulk heterojunction of poly(3-hexylthiophene) (P3HT) and a soluble C_(70) derivative, [6,6]-phenyl C_(71) butyric acid methyl ester (PCBM-70), were fabricated. Power conversion efficiency of individual P3HT/PCBM-70 cells was estimated to be 4.1 % for AM1.5 G illumination. Modules of one to four cells connected in series produced open-circuit voltages V_(OC) that linearly depend on the number of cells N as V_(OC) = N × 0.621 V with a nearly constant short-circuit current of 1.4 ± 0.1 mA. Separately, shelf lifetimes of more than one year were achieved for pentacene/C_(60) solar cells by encapsulation with a 200-nm-thick layer of Al_2O_3 deposited by atomic layer deposition (ALD). In addition, the ALD process improved the open-circuit voltage and power conversion efficiency of the solar cells by thermal annealing that occurs during the process.