Three terminal tandem solar generation unit
The present invention refers to a three terminal tandem solar generation unit ( 1 ) comprising: —a first absorbing layer ( 7 ) made of a perovskite type compound, —a second absorbing layer ( 11, 11 ′), —a first and a second interdigitated front contacts ( 5 a, 5 b ) arranged on the front side of the first absorbing layer ( 7 ), the first front contact ( 5 a ) having a first polarity and the second front contact ( 5 b ) having a second polarity, —a back contact ( 17, 17 ′) having the first or the second polarity arranged on the back side of the second absorbing layer ( 11, 11 ′), —an interface layer ( 9, 90, 9′, 90 ′) arranged between the first ( 7 ) and the second ( 11, 11 ′) absorbing layers comprising a first semiconductor sub-layer ( 9 a, 90 a, 9 a′, 90 a ′) doped according to the first polarity and a second sub-layer ( 9 b, 90 b, 9 b′, 90 b ′) doped according to the second polarity and configured for enabling carriers associated with a polarity different than the polarity of the back contact ( 17, 17 ′) to be transferred from the second absorbing layer ( 11, 11 ′) to the first absorbing layer ( 7 ) to be collected by the front contact ( 5 a, 5 b ) having a polarity different than the polarity of the back contact ( 17, 17 ′).
1. A three terminal tandem solar generation unit comprising:
a first absorbing layer made of a compound having a perovskite type crystalline structure and comprising a front side and a back side,
a second absorbing layer comprising a front side and a back side,
a first and a second interdigitated front contacts arranged on the front side of the first absorbing layer, the first front contact having a first polarity and the second front contact having a second polarity,
a back contact having the first or the second polarity arranged on the back side of the second absorbing layer,
an interface layer arranged between the first and the second absorbing layers comprising a first semiconductor sub-layer doped according to the first polarity and a second sub-layer doped according to the second polarity and configured for enabling carriers associated with a polarity different than the polarity of the back contact to be transferred from the second absorbing layer to the first absorbing layer to be collected by the first front contact or second front contact having a polarity different than the polarity of the back contact,
wherein the first polarity corresponds to the p-type polarity having holes as associated carriers and the second polarity corresponds to the n-type polarity having electrons as associated carriers; and
wherein the back contact has the first polarity and comprises a back surface field and the second absorbing layer is doped according to the first polarity.
2. The three terminal tandem solar generation unit of claim 1 , wherein the interface layer is a tunnel junction layer.
3. The three terminal tandem solar generation unit of claim 1 , wherein the interface layer is a recombination layer made of two sublayers of transparent conductive oxides.
4. The three terminal tandem solar generation unit of claim 1 , wherein the second absorbing layer is made of crystalline silicon.
5. The three terminal tandem solar generation unit of claim 1 , wherein the second absorbing layer is made of one alloy among the following alloys:
a III-V semiconductor alloy,
a compound having a perovskite type crystalline structure,
Copper Indium Gallium Selenide “CIGS”, and
Cadmium Telluride “CdTe”.
6. The three terminal tandem solar generation unit of claim 1 , wherein the tunnel junction comprises a sub-layer highly doped according to the first polarity and arranged in contact of the front side of the second absorbing layer and a sublayer doped according to the second polarity and arranged in contact of the back side of the first absorbing layer.
7. The three terminal tandem solar generation unit of claim 1 , wherein the back contact has the second polarity and the second absorbing layer is doped according to the second polarity.
8. The three terminal tandem solar generation unit of claim 7 , wherein the tunnel junction comprises a sub-layer highly doped according to the second polarity and arranged in contact of the front side of the second absorbing layer and a sublayer doped according to the first polarity and arranged in contact of the back side of the first absorbing layer.
9. The three terminal tandem solar generation unit of claim 1 , wherein the first front contact, second front contact and back contact are passivated contacts.
10. The three terminal tandem solar generation unit of claim 1 , wherein the first and the second front contacts comprise respectively a Hole Transport Layer “HTL” and an Electron Transport Layer “ETL”.
11. The three terminal tandem solar generation unit of claim 10 , wherein the hole transport layer is made of one among:
Nickel oxide “NiOx”,
Mobyldenum oxide “MoOx”,
Tungsten oxide “WOx”,
2,2′,7,7′-Tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene “Spiro-OMeTAD”,
poly(triarylamine) “PTAA”,
poly(3-hexylthiophène) “P3HT”,
poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) “PEDOT:PSS”,
Copper(I) thiocyanate “CuSCN”,
Cobalt oxide “CoOx”,
Chromium oxide “CrOx”,
Copper(I) iodide “CuI”,
Copper sulfide “CuS”,
Copper oxide “CuOx”,
Vanadium oxide “Vox”,
and the electron transport layer is made of one among:
Tin oxide “SnOx”,
Titanium oxide “TiOx”,
Zinc oxide “ZnOx”,
carbon, C60 and derivatives,
Zirconia “ZrOx”,
graphite,
graphene, and
graphene oxide “rGO”.
12. The three terminal tandem solar generation unit of claim 1 , wherein the front and back contacts comprise a metallic grid or a transparent conductive oxide grid.