ROLL-TO-ROLL NON-VACUUM DEPOSITION OF TRANSPARENT CONDUCTIVE ELECTRODES
Methods and devices are provided for improved photovoltaic devices. Non-vacuum deposition of transparent conductive electrodes in a roll-to-roll manufacturing environment is disclosed. In one embodiment, a method is provided for forming a photovoltaic device. The method comprises processing a precursor layer in one or more steps to form a photovoltaic absorber layer; depositing a smoothing layer to fill gaps and depression in the absorber layer to reduce a roughness of the absorber layer; adding an insulating layer over the smooth layer; and forming a web-like layer of conductive material over the insulating layer. By way of nonlimiting example, the web-like layer of conductive material comprises a plurality of carbon nanotubes. In some embodiments, the absorber layer is a group IB-IIIA-VIA absorber layer.
1 . A method comprising:
processing a precursor layer in one or more steps to form a photovoltaic absorber layer;
depositing a transparent material layer loaded with conductive nanopowder or nanoparticles.
2 . The method of claim 1 further comprising forming a sacrificial layer coupled to the transparent material layer.
3 . The method of claim 1 wherein the transparent material layer includes a web-like layer of conductive material comprises a plurality of metallic nanowires.
4 . The method of claim 1 wherein the photovoltaic absorber layer comprises of a group IB-IIIA-VIA material.
5 . The method of claim 1 wherein the photovoltaic absorber layer prior to deposition of a smoothing layer has peaks between about 10 to about 1000 nm.
6 . The method of claim 1 wherein the photovoltaic absorber layer prior to deposition of a smoothing layer has peaks between about 10 to about 500 nm.
7 . The method of claim 1 wherein the photovoltaic absorber layer prior to deposition of a smoothing layer has peaks between about 10 to about 100 nm.
8 . The method of claim 1 , further comprising depositing a smoothing layer on the photovoltaic absorber layer, wherein the smoothing layer comprises an electrically conductive material.
9 . The method of claim 8 wherein the smoothing layer comprises one or more of the following: sol gel TCO or TCO particles.
10 . The method of claim 8 wherein the smoothing layer comprises ZnO:Al of a thickness of about 100 nm or less.
11 . The method of claim 8 wherein the smoothing layer comprises ZnO:Al of a thickness of about 150 nm or less.
12 . The method of claim 8 wherein the smoothing layer comprises ZnO:Al of a thickness of about 200 nm or less.
13 . The method of claim 8 wherein the smoothing layer and web layer have substantially the same thickness.
14 . The method of claim 8 wherein the smoothing layer comprises a electrically conductive leveling layer.
15 . A method comprising:
processing a precursor layer in one or more steps to form a photovoltaic absorber layer;
depositing a smoothing, insulating layer to fill gaps and depression in the absorber layer to reduce a roughness of the absorber layer.
16 . The method of claim 15 wherein the smoothing insulator is sufficient to cover all peaks of the rough absorber, but sufficiently thin to allow electrons to pass out of the absorber layer.
17 . The method of claim 15 wherein the smoothing insulator conformally covers all peaks in the rough absorber.
18 . The method of claim 15 further comprising creating the absorber layer by processing the precursor layer into a solid film and then thermally reacting the solid film in an atmosphere containing at least an element of Group VIA of the Periodic Table to form the photovoltaic absorber layer.
19 . The method of claim 15 further comprising creating the absorber layer by thermal reaction of the precursor layer in an atmosphere containing at least an element of Group VIA of the Periodic Table to form the photovoltaic absorber layer.
20 . The method of claim 15 wherein Group IB and/or IIIA hydroxide comprises indium-gallium hydroxide.