Four Terminal Multi-Junction Thin Film Photovoltaic Device and Method
A multi-junction photovoltaic cell device. The device includes a lower cell and an upper cell, which is operably coupled to the lower cell. In a specific embodiment, the lower cell includes a lower glass substrate material, e.g., transparent glass. The lower cell also includes a lower electrode layer made of a reflective material overlying the glass material. The lower cell includes a lower absorber layer overlying the lower electrode layer. In a specific embodiment, the absorber layer is made of a semiconductor material having a band gap energy in a range of Eg=0.7 to 1 eV, but can be others. In a specific embodiment, the lower cell includes a lower window layer overlying the lower absorber layer and a lower transparent conductive oxide layer overlying the lower window layer. The upper cell includes a p+ type transparent conductor layer overlying the lower transparent conductive oxide layer. In a preferred embodiment, the p+ type transparent conductor layer is characterized by traversing electromagnetic radiation in at least a wavelength range from about 700 to about 630 nanometers and filtering electromagnetic radiation in a wavelength range from about 490 to about 450 nanometers. In a specific embodiment, the upper cell has an upper p type absorber layer overlying the p+ type transparent conductor layer. In a preferred embodiment, the p type conductor layer made of a semiconductor material has a band gap energy in a range of Eg=1.6 to 1.9 eV, but can be others. The upper cell also has an upper n type window layer overlying the upper p type absorber layer, an upper transparent conductive oxide layer overlying the upper n type window layer, and an upper glass material overlying the upper transparent conductive oxide layer.
1 . A method for using a multi-junction photovoltaic cell, the method comprising:
irradiating sunlight through an upper cell operably coupled to a lower cell, the upper cell comprising a p+ type transparent conductor layer overlying a lower transparent conductive oxide layer;
selectively traversing electromagnetic radiation from the sunlight in at least a wavelength range from about 700 to about 630 nanometers and filtering electromagnetic radiation in a wavelength range from about 490 to about 450 nanometers through the p+ type transparent conductor layer.
2 . The method of claim 1 further comprising:
absorbing, by an absorber layer of the lower cell, the electromagnetic radiation from the sunlight in at least the wavelength range from about 700 to about 630 nanometers.
3 . The method of claim 2 wherein the absorber layer comprises Cu 2 SnS 3 , FeS 2 , or CuInSe 2 .
4 . The method of claim 2 wherein the absorber layer has a band gap energy of between 0.7 eV to 1 eV.
5 . The method of claim 1 wherein the p+ type transparent conductor layer comprises ZnTe material.
6 . The method of claim 5 wherein the ZnTe material is crystalline.
7 . The method of claim 5 wherein the ZnTe material is polycrystalline.
8 . The method of claim 1 wherein the p+ type transparent conductor layer is doped with at least one species from a group comprising Cu, Cr, Mg, O, Al, and N.
9 . The method of claim 1 wherein the p+ type transparent conductor layer is characterized by a band gap energy of between 1.6 eV and 1.9 eV.
10 . A method comprising:
exposing a P+ type transparent conductor layer of a top cell in a multi-junction photovoltaic cell to incident sunlight;
allowing, by the P+ type transparent conductor layer, electromagnetic radiation from the sunlight with a wavelength of between 630 nanometers and 700 nanometers to pass through the P+ type transparent conductor layer to reach an absorber layer of a bottom cell operatively coupled to the top cell; and
blocking, by the P+ type transparent conductor layer, electromagnetic radiation having an associated wavelength of between 450 and 490 nanometers.
11 . The method of claim 10 further comprising blocking, by the absorber layer, the electromagnetic radiation from the sunlight with a wavelength of between 630 nanometers and 700 nanometers.
12 . The method of claim 10 wherein the absorber layer comprises Cu 2 SnS 3 , FeS 2 , or CuInSe 2 .
13 . The method of claim 10 wherein the p+ type transparent conductor layer comprises ZnTe material.
14 . The method of claim 13 wherein the ZnTe material is crystalline.
15 . The method of claim 13 wherein the ZnTe material is polycrystalline.
16 . The method of claim 10 wherein the p+ type transparent conductor layer is doped with at least one species from a group comprising Cu, Cr, Mg, O, Al, and N.
17 . The method of claim 10 wherein the p+ type transparent conductor layer is characterized by a band gap energy of between 1.6 eV and 1.9 eV.
18 . The method of claim 10 wherein the absorber layer has a band gap energy of between 0.7 eV to 1.1 eV.