Methods and systems for use with photovoltaic devices

Patent metadata

Field	Value
Publication number	US-11870002-B2
Application number	US-202117319989-A
Country	US
Kind code	B2
Filing date	May 13, 2021
Priority date	May 13, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

According to embodiments provided herein, the performance of photovoltaic device can be improved by rapidly heating an absorber layer of a device in open-circuit to a high temperature for a short period of time followed by rapid quenching. The rapid heating may be accomplished by one or more pulses of high intensity electromagnetic energy. The energy may be visible light. The energy may be absorbed primarily in the absorber layer, such that the absorber layer is preferentially heated, promoting chemical reactions of dopant complexes. The dopant chemical reactions disrupt compensating defect complexes that have formed in the device, and regenerate active carriers.

First claim

What is claimed is:

1. A method of treating a fully-formed photovoltaic device disconnected from a load to form an open circuit, the device having an absorber layer comprising a group II-VI p-type semiconductor material doped with an element from group IB, the method comprising:
heating at least a portion of the absorber layer of the photovoltaic device to a temperature in a range of 200 C to 1000 C for a duration of up to 60 seconds to promote at least one dopant chemical reaction in the absorber layer; and
quenching the at least one dopant chemical reaction by ending the heating and allowing the absorber layer of the photovoltaic device to cool, whereby the absorber layer reaches a temperature below 100 C within 120 seconds after initiating the heating step,
wherein the absorber layer comprises cadmium and tellurium and is doped with copper and chlorine, and the heating promotes dissociation of Cl i —Cu Cd complexes.

2. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy having at least one wavelength in a range of 200-1200 nm.

3. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy, and a source of the electromagnetic energy is selected from the set consisting of: a broad spectrum flash lamp, a metal halide lamp, a xenon discharge light, a halogen lamp, a collimated beam, a laser, a gas laser, a continuous wave laser, a pulsed laser, and a light emitting diode.

4. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy, wherein the one or more pulses of electromagnetic energy are directed at a surface of the device for a duration in a range from 0.001 milliseconds to 10 seconds.

5. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy, wherein the one or more pulses of electromagnetic energy are configured to deliver radiant exposure at a level of from 0.1 J/cm 2 to 2000 J/cm 2 .

6. The method of claim 1 , wherein the steps of heating and quenching are performed in rapid succession to define a temperature profile in the absorber layer, wherein:
the absorber layer reaches at least 300 C within 5 seconds and cools to below 100 C within 10 seconds.

7. The method of claim 1 , wherein the heating step produces a temperature in a range of 270 C to 330 C in the absorber layer.

8. The method of claim 1 , wherein the group II-VI p-type semiconductor material comprises selenium.

9. The method of claim 1 , wherein the absorber layer is doped with silver.

10. The method of claim 1 , wherein:
a free carrier concentration of the absorber layer of the photovoltaic device prior to the heating is less than 5×10 14 cm −3 , and the free carrier concentration of the absorber layer of the photovoltaic device following the quenching is in a range between 1×10 15 cm −3 and 1×10 17 cm −3 .

11. The method of claim 1 , wherein the heating comprises: simultaneously directing electromagnetic energy to an area of less than 50% of an energy side of the photovoltaic device, wherein the electromagnetic energy is simultaneously directed to an area of 0.0001% to 50.0%.

12. The method of claim 1 , wherein the heating comprises: simultaneously directing electromagnetic energy to an area of 90% to 100% of an energy side of the photovoltaic device.

13. The method of claim 1 , wherein the photovoltaic device is installed as a module connected to an array and wherein the method further comprises: disconnecting the module from the array prior to the heating step; and reconnecting the module to the array after the quenching step.

14. The method of claim 1 , wherein the quenching step further comprises: actively cooling a surface of the photovoltaic device by directing a fluid to contact the surface, wherein the fluid has a temperature in a range between 5 C to 45 C.

15. A method of reactivating a dopant in a degraded photovoltaic device, the device having an absorber layer comprising a group II-VI p-type semiconductor material doped with an element from group IB, the method comprising:
disconnecting the photovoltaic device from a load to form an open circuit;
directing electromagnetic energy toward an energy side of the device, for a duration of up to 60 seconds, to heat at least a portion of the absorber layer of the photovoltaic device to a temperature in a range of 200 C to 1000 C and promote at least one dopant chemical reaction in the absorber layer; and
quenching the at least one dopant chemical reaction by ending the heating and allowing the absorber layer of the photovoltaic device to cool, whereby the absorber layer reaches a temperature below 100 C within 120 seconds after initiating the heating step,
wherein the absorber layer comprises cadmium and tellurium and is doped with copper and chlorine, and the heating promotes dissociation of Cl i —Cu Cd complexes.

16. The method of claim 15 , wherein the method is performed on an installed photovoltaic device in situ.

17. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy having at least one wavelength in a range of 400-700 nm.

18. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy, wherein the one or more pulses of electromagnetic energy are directed at a surface of the device for a duration in a range from 0.001 milliseconds to 5 seconds.

19. The method of claim 1 , wherein the step of heating is performed by one or more pulses of electromagnetic energy, wherein the one or more pulses of electromagnetic energy are configured to deliver radiant exposure at a level of from 1.0 J/cm 2 to 500 J/cm 2 .

20. The method of claim 1 , wherein the steps of heating and quenching are performed in rapid succession to define a temperature profile in the absorber layer, wherein:
the absorber layer reaches at least 400 C within 5 seconds and cools to below 100 C within 10 seconds.

Assignees

• First Solar Inc

Inventors

• Krasikov Dmitry
• Grover Sachit
• Sankin Igor

Classifications

• H10F77/1233 Primary

  characterised by the dopants · CPC title

• H10F10/162

  comprising only Group II-VI materials, e.g. CdS/CdTe photovoltaic cells · CPC title

• H10F10/10

  having potential barriers · CPC title

• H10F71/128 Primary

  Annealing · CPC title

• H10F19/807

  Double-glass encapsulation, e.g. photovoltaic cells arranged between front and rear glass sheets · CPC title