Disclosed is a tandem solar cell according to an aspect including: a silicon lower cell; a perovskite upper cell disposed on the silicon lower cell; and a bonding layer for bonding the silicon lower cell and the perovskite upper cell between the silicon lower cell and the perovskite upper cell, wherein the front surface portion of the silicon lower cell being in contact with the bonding layer includes a texture structure, the bonding layer includes a first transparent electrode layer formed on the sidewall of the texture structure, a buried layer filling concave portions of the texture structure on the first transparent electrode layer, and a second transparent electrode layer on top surfaces of the buried layer, the first transparent electrode layer and the texture structure.

An exemplary transparent tandem organic solar cell comprises a transparent substrate; a first transparent electrode disposed on a surface of the transparent substrate; and a series of interconnecting organic active layers disposed on a surface of the first transparent electrode. The series of organic interconnecting active layers comprise at least a front sub-cell that blocks ultraviolet wavelengths from passing through the front sub-cell; and a back sub-cell that blocks infrared wavelengths from passing through the back sub-cell. The solar cell further comprises a distributed Bragg reflector disposed on a surface of the back sub-cell, wherein the distributed Bragg reflector reflects unblocked infrared photons at an interface between the back sub-cell and the distributed Bragg reflector. Additionally, the series of interconnecting organic active layers are configured to allow wavelengths of visible light to pass through the transparent tandem organic solar cell, wherein the transparent tandem organic solar cell is fully transparent.

The invention relates to a process for producing a multi-junction device comprising a layer of a crystalline A/M/X material, which crystalline A/M/X material comprises a compound of formula [A].sub.a[M].sub.b[X].sub.c, wherein: [A] comprises one or more A cations; [M] comprises one or more M cations which are metal or metalloid cations; [X] comprises one or more X anions; a is a number from 1 to 6; b is a number from 1 to 6; and c is a number from 1 to 18; and wherein the process comprises forming the layer of the crystalline A/M/X material by disposing a film-forming solution on a substrate, wherein the film-forming solution comprises: (a) one or more M cations; and (b) a solvent; wherein the solvent comprises (i) an aprotic solvent; and (ii) an organic amine, and wherein the substrate comprises: a photoactive region comprising a photoactive material, and a charge recombination layer which is disposed on the photoactive region by solution-deposition. Multi junction devices are also the subject of the present invention.

The present invention relates to a tandem solar cell which comprises: a perovskite solar cell comprising a perovskite absorption layer; a silicon solar cell placed under the perovskite solar cell; a junction layer placed between the perovskite solar cell and the silicon solar cell; an upper electrode placed on the perovskite solar cell; and a lower electrode placed under the silicon solar cell.

An optoelectronic device comprising two photovoltaic absorber materials of CdSeTe and perovskite and their functional component layers that are monolithically integrated into a bifacial tandem solar cell structure.

Methods of annealing and/or sintering a transparent conductive oxide (TCO) film disclosed, and wherein the TCO film comprises indium tin oxide film (ITO), fluorine-doped tin film (FTO), indium doped zinc oxide (IZO), or aluminum-doped zinc oxide (AZO). Such methods involve irradiating the TCO film with a light source and where the annealing and/or sintering is selective to the TCO film.

There is disclosed an organic photovoltaic device comprising at least one first subcell comprising at least one first small molecular weight material deposited by solution processing, and at least one second subcell comprising a weight at least one second small molecular material deposited by vacuum evaporation. Also disclosed herein is a method for preparing an organic photovoltaic device comprising at least one first subcell comprising at least one first small molecular weight material and at least one second subcell comprising at least one second small molecular weight material, the method comprising depositing at least one first small weight material by solution processing; and depositing at least one second small weight material by vacuum evaporation.

There is disclosed an organic photovoltaic device comprising at least one first subcell comprising at least one first small molecular weight material deposited by solution processing, and at least one second subcell comprising a weight at least one second small molecular material deposited by vacuum evaporation. Also disclosed herein is a method for preparing an organic photovoltaic device comprising at least one first subcell comprising at least one first small molecular weight material and at least one second subcell comprising at least one second small molecular weight material, the method comprising depositing at least one first small weight material by solution processing; and depositing at least one second small weight material by vacuum evaporation.

Disclosed herein are organic photosensitive optoelectronic device comprising a first layer comprising one or more of a first layer material, a second layer comprising one or more of a second layer material, and a third layer comprising one or more of a third layer material. The second layer may be dissolved in a semi-orthogonal solvent. The first layer and the third layer may be very slightly soluble or practically insoluble in the semi-orthogonal solvent.

Disclosed herein are organic photosensitive optoelectronic device comprising a first layer comprising one or more of a first layer material, a second layer comprising one or more of a second layer material, and a third layer comprising one or more of a third layer material. The second layer may be dissolved in a semi-orthogonal solvent. The first layer and the third layer may be very slightly soluble or practically insoluble in the semi-orthogonal solvent.