Photovoltaic devices and method of making

Abstract

A photovoltaic device is presented. The photovoltaic device includes a buffer layer disposed on a transparent conductive oxide layer; a window layer disposed on the buffer layer; and an interlayer interposed between the transparent conductive oxide layer and the window layer. The interlayer includes a metal species, wherein the metal species includes gadolinium, beryllium, calcium, barium, strontium, scandium, yttrium, hafnium, cerium, lutetium, lanthanum, or combinations thereof. A method of making a photovoltaic device is also presented

Description

BACKGROUND[0001]The invention generally relates to photovoltaic devices. More particularly, the invention relates to photovoltaic devices that include an interlayer, and methods of making the photovoltaic devices.[0002]Thin film solar cells or photovoltaic (PV) devices typically include a plurality of semiconductor layers disposed on a transparent substrate, wherein one layer serves as a window layer and a second layer serves as an absorber layer. The window layer allows the penetration of solar radiation to the absorber layer, where the optical energy is converted to usable electrical energy. The window layer further functions to form a heterojunction (p-n junction) in combination with an absorber layer. Cadmium telluride / cadmium sulfide (CdTe / CdS) heterojunction-based photovoltaic cells are one such example of thin film solar cells, where CdS functions as the window layer.[0003]However, thin film solar cells may have low conversion efficiencies. Thus, one of the main focuses in th...

AI Technical Summary

Benefits of technology

This patent proposes a photovoltaic device that includes a buffer layer, a window layer, and an interlayer interposed between the transparent conductive oxide layer and the window layer. The interlayer includes a metal species selected from the group consisting of gadolinium, beryllium, calcium, barium, strontium, scandium, yttrium, hafnium, cerium, lutetium, lanthanum, and combinations thereof. The technical effects of this patent include improved photovoltaic device efficiency, increased durability, and reduced costs.

Problems solved by technology

However, thin film solar cells may have low conversion efficiencies.

Absorption of light by the window layer may be one of the phenomena limiting the conversion efficiency of a PV device.

However, for most of the thin-film PV devices, if the window layer is too thin, a loss in performance can be observed due to low open circuit voltage (VOC) and fill factor (FF).

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