Multi-junction optoelectronic device comprising device interlayer

A multi-junction device according to any one of the preceding claims wherein the refractive index n(λ) of the charge recombination layer material at the wavelength λ is less than 3.5, optionally less than or equal to 3, and more particularly less than or equal to 2.5.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer material is semi-transparent, optionally wherein the charge recombination layer material has a mean optical transparency in the visible to near infrared range of the spectrum which is equal to or greater than about 50%.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer material comprises a wide band-gap semiconductor.

A multi-junction device according to any one of the preceding claims wherein the first photoactive material has a band gap Eg1 and wherein the second photoactive material has a band gap Eg2, wherein Eg1 is greater than Eg2.

A multi-junction device according to any one of the preceding claims wherein the first photoactive material has a band gap Eg1 and wherein the charge recombination layer material has a band gap Eg, wherein Eg is greater than Eg1.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer material has a band gap Eg, the first photoactive material has a band gap Eg1, and the second photoactive material has a band gap Eg2, wherein Eg is greater than Eg1 and Eg1 is greater than Eg2, optionally wherein Eg is at least 2.0 eV, more particularly wherein Eg is at least 3.0 eV and Eg1 is 2.0 eV or less.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer has a thickness of at least 5 nm, optionally a thickness of from 20 to 300 nm, more particularly a thickness of from 50 to 200 nm, or a thickness of from 75 to 150 nm.

A multi-junction device according to any one of the preceding claims wherein the wavelength λ is a wavelength of from 500 and 1100 nm, optionally a wavelength of from 600 to 1200 nm, optionally a wavelength of from 600 and 1000 nm, more particularly a wavelength of from 800 nm to 1000 nm, for instance a wavelength of 850 nm.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer material comprises a metal oxide, a metal nitride or a metal sulfide,

• optionally wherein the material in the charge recombination layer comprises TiO2, metal doped-TiO2, SrTiO3, BaTiO3, Cr2O3, CuCrO2, ZnS, ZrO2, TiN, AlN and GaN,
• more particularly wherein the material in the charge recombination layer comprises TiO2 or metal-doped TiO2.

A multi-junction device according to any one of the preceding claims wherein the charge recombination layer material comprises (a) TiO2 or metal-doped TiO2 and (b) a transparent conducting oxide,

• optionally wherein the charge recombination layer material comprises a blend of (a) and (b);
• more particularly wherein the transparent conducting oxide is indium tin oxide (ITO).

A multi-junction device according to any one of the preceding claims, wherein [A] comprises one or more A cations including at least one organic cation.

A multi-junction device according to any one of the preceding claims, wherein [M] comprises two or more different M cations.

A multi-junction device according to any one of the preceding claims wherein each X anion is a halide, optionally wherein [X] comprises two or more different halide anions.

A multi-junction device according to any one of the preceding claims wherein the photoactive regions each further comprise one or more charge transporting layers,

• optionally wherein each photoactive region further comprises an electron transporting (n-type) layer and a hole transporting (p-type) layer,
• more particularly wherein each photoactive region comprises the layer of a photoactive material disposed between an electron transporting (n-type) layer and a hole transporting (p-type) layer.

A multi-junction device according to any one of the preceding claims further comprising an optical spacer layer,

• preferably wherein the optical spacer layer comprises a transparent conducting oxide, TiO2, metal-doped TiO2 or TiN.

A multi-junction device according to any one of the preceding claims further comprising a first electrode and a second electrode;

• optionally wherein the first electrode comprises a transparent conducting oxide, and
• optionally wherein the second electrode comprises an elemental metal.

A multi-junction device according to any one of the preceding claims wherein the multi-junction device is an optoelectronic device, optionally wherein the optoelectronic device is a photovoltaic device or a light-emitting device.