Finger structures protruding from absorber layer for improved solar cell back contact

摘要

Thin film photovoltaic devices that include a transparent substrate; a transparent conductive oxide layer on the transparent substrate; a n-type window layer on the transparent conductive oxide layer; a p-type absorber layer on the n-type window layer; and, a back contact on the p-type absorber layer are provided. The p-type absorber layer comprises cadmium telluride, and forms a photovoltaic junction with the n-type window layer. Generally, the p-type absorber layer defines a plurality of finger structures protruding from the p-type absorber layer into the back contact. The finger structures can have an aspect ratio of about 1 or greater and/or can have a height that is about 20% to about 200% of the thickness of the p-type absorber layer. Methods of forming such finger structures protruding from a back surface of the p-type absorber layer are also provided.

主权项

1. A thin film photovoltaic device, comprising:
a transparent substrate; a transparent conductive oxide layer on the transparent substrate; a n-type window layer on the transparent conductive oxide layer; a p-type absorber layer on the n-type window layer, wherein the p-type absorber layer comprises cadmium telluride, and wherein the n-type window layer and the p-type absorber layer form a photovoltaic junction; and, a back contact on the p-type absorber layer, wherein the p-type absorber layer defines a plurality of finger structures protruding from the p-type absorber layer into the back contact, the finger structures comprising tellurium-rich cadmium telluride and having an aspect ratio of about 1 or greater; wherein the back contact comprises a conductive paste layer on the p-type absorber layer and a metal layer on the conductive paste layer; wherein the finger structures protrude through the conductive paste layer and directly contact the metal layer of the back contact.