Combination of Vacuum and Solution Processes for Stable Indoor Organic Solar Cell under LED Illumination

The use of tiny, micro-powered electronic devices in indoor environments is increasing daily. The demand for high-performing organic photo- voltaics (OPVs) to power these devices has been rapidly growing because OPVs have favorable absorption properties for indoor environments, excellent mechanical flexibility, and other advantageous attributes. Recently, inexpensive, less acidic, and water-processable polyaniline:poly (4-styrenesulfonic acid) (PANI:PSS) was shown to deliver remarkably high performance as the hole transport layer (HTL) in an indoor OPV device with poly(3-hexylthiophene): indene-C60 bisadduct as the active layer. However, PANI:PSS has not been tested in combination with other active materials, although its universal applicability is of key importance for its commercialization. Thus, we tested the potentiality of using PANI:PSS as the HTL of a highly suitable active material, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl][3-fluoro-2- [(2-ethylhexyl-l)carbonyl]thieno[3,4-b]thiophendiyl]:phenyl-C70-butyric acid methyl ester (PTB7:PC 70 BM) in an OPV device under an LED lamp. The results reveal that the OPV device based on the PANI:PSS HTL and PTB7:PC 70 BM as the active material has high efficiency (11.80%) and a maximum power density of 42.5 𝜇 W/cm 2 under a 1,000 lx LED.