Solution processed metal oxide thin film hole transport layers for high performance organic solar cells
A method for the application of solution processed metal oxide hole transport layers in organic photovoltaic devices and related organic electronics devices is disclosed. The metal oxide may be derived from a metal-organic precursor enabling solution processing of an amorphous, p-type metal oxide. An organic photovoltaic device having solution processed, metal oxide, thin-film hole transport layer.
1. A method comprising:
forming an indium tin oxide (ITO) layer on a substrate;
depositing a hole transport layer (HTL) on the ITO layer, wherein the HTL comprises an amorphous, p-type NiO;
annealing the HTL;
forming an active layer on the annealed HTL, wherein the active layer comprises a donor region and an acceptor region; and
forming a contact on the active layer, wherein:
the contact comprises a cathode, and
the depositing is performed by spin-coating a diluted nickel ink on the ITO layer.
2. The method according to claim 1 , wherein the active layer comprises a polymer and a fullerene.
3. The method according to claim 2 , wherein the polymer comprises poly(3-hexylthiophene) (P3HT) and the fullerene comprises [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM).
4. The method according to claim 1 , wherein the spin-coating is performed at approximately 4000 rpm for approximately 60 seconds, and the annealing is performed at a temperature of approximately 250° C. for a period of time of approximately 1 hour.
5. The method according to claim 1 , wherein the spin-coating is performed at approximately 4000 rpm, and the annealing is performed in air.
6. The method according to claim 1 , wherein the HTL forms a thin-film.
7. The method according to claim 6 , wherein the thin-film has a thickness of approximately 10 nm.
8. The method according to claim 1 , wherein the active layer comprises a PCDTBT/[6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) bulk heterojunction.
9. The method according to claim 1 , further comprising:
exposing the HTL to an oxygen plasma after the depositing.
10. 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.
11. The method according to claim 10 , further comprising:
annealing the metal-organic ink in air after the solution deposition.
12. The method according to claim 10 , wherein the TCO comprises a ZnO-based material.
13. The method according to claim 12 , wherein the ZnO-based material is gallium-doped.
14. The method according to claim 12 , wherein the ZnO-based material is aluminum-doped.
15. The method according to claim 10 , further comprising:
exposing the HTL to an O 2 -plasma treatment after the HTL is formed.
16. The method of claim 10 , further comprising:
forming an active layer on the HTL, wherein the active layer comprises a donor region and an acceptor region; and
forming a contact on the active layer, wherein the contact comprises a cathode.
17. 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-C 61 -butyric acid methyl ester (PCBM) bulk heterojunction.