Solution processed metal oxide thin film hole transport layers for high performance organic solar cells

A method comprising:

• forming a transparent conducting oxide (TCO) layer on a substrate;
• and
• forming a hole transport layer (HTL) on the TCO layer by solution deposition of a metal-organic ink using ink-jet or continuous flow printing, wherein:
• the HTL comprises an amorphous, p-type metal oxide, and
• the metal-organic ink comprises a complex in which the p-type metal oxide is in solution and coordinates to one or more diamine groups suspended in a solvent.

A method comprising:

• forming an indium tin oxide (ITO) layer on a substrate;
• forming by solution deposition a hole transport layer (HTL) on the ITO layer, wherein the HTL comprises an amorphous, p-type NiO;
• and
• forming an active layer on the HTL, wherein the active layer comprises a PCDTBT/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction.