US 8,263,176 B2 · Method for fabricating a photovoltaic element with stabilised efficiency

Abstract

A method for fabricating a photovoltaic element with stabilized efficiency is proposed. The method comprises the following steps: preparing a boron-doped, oxygen-containing silicon substrate; forming an emitter layer on a surface of the silicon substrate; and a stabilization treatment step. The stabilization treatment step comprises keeping the temperature of the substrate during a treatment time within a selectable temperature range having a lower temperature limit of 50° C., preferably 90° C., more preferably 130° C. and even more preferably 160° C. and an upper temperature limit of 230° C., preferably 210° C., more preferably 190° C. and even more preferably 180° C., and generating excess minority carriers in the silicon substrate during the treatment time, for example, by illuminating the substrate or by applying an external voltage. This method can be used to fabricate a photovoltaic element, e.g. a solar cell or a solar module having an efficiency which is stable at a value higher than that of photovoltaic elements fabricated without the stabilization treatment step.

Claims12

Dependent claims

A method for fabricating a photovoltaic element with stabilized efficiency, comprising the following steps:

providing a boron-doped, oxygen-containing silicon substrate;
forming an emitter layer on a surface of the silicon substrate;
forming electrical contacts on the silicon substrate;
performing stabilization treatment, comprising:
maintaining the temperature of the substrate during a treatment time t within a selectable temperature range having a lower temperature limit of 50° C. and an upper temperature limit of 230° C.;
and
generating excess minority charge carriers in the silicon substrate during the treatment time;
wherein the step of generating excess minority carriers involves applying an external electrical voltage to the contacts;
wherein the treatment time t in minutes during which the substrate is held within the selectable temperature range is given by:
t
≥
a
(
y
+
b
)
c
*
exp
⁡
(
x
(
T
+
273
)
)
where T is the average temperature of the selectable temperature range in ° C. during the treatment time, y is the current density through the photovoltaic element brought about by the applied voltage in A/cm2 and a=4.247*10−14, b=0.00286, c=0.887 and x=12550.

27 more elements

Dependencies are inferred from the claim text.

Method for fabricating a photovoltaic element with stabilised efficiency

Life of this patent

Method for fabricating a photovoltaic element with stabilised efficiency

Life of this patent

Abstract

Claims12