Various aspects of the present invention are directed to providing a perovskite solar cell, and has a technical feature in that excellent stability and high efficiency are simultaneously secured by using a solid solution having a specific composition as a light absorber.

An OLED panel may be embedded with a near-infrared organic photosensor and may be configured to implement biometric recognition without an effect on an aperture ratio of an OLED emitter. The OLED panel may include a substrate, an OLED stack on the substrate and configured to emit visible light, and an NIR light sensor stack between the substrate and the OLED stack and including an NIR emitter configured to emit NIR light and an NIR detector. The OLED panel may be included in one or more various electronic devices.

A photodetection element includes: a photoelectric conversion structure that contains a first material having an absorption coefficient higher than an absorption coefficient of monocrystalline silicon for light of a first wavelength, for which monocrystalline silicon exhibits absorption, and generates positive and negative charges by absorbing a photon; and an avalanche structure that includes a monocrystalline silicon layer, in which avalanche multiplication occurs as a result of injection of at least one selected from the group consisting of the positive and negative charges from the photoelectric conversion structure. The first material includes at least one selected from the group consisting of an organic semiconductor, a semiconductor-type carbon nanotube, and a semiconductor quantum dot.

There is provided a photovoltaic device that comprises a photoactive region, the photoactive region comprising a perovskite material of general formula A.sub.1-xA.sub.xBX.sub.3-yX.sub.y, wherein A is a formamidinium cation (HC(NH).sub.2).sub.2.sup.+), A is a caesium cation (Cs.sup.+) B is at least one divalent inorganic cation, X is iodide and X is bromide, and x is greater than 0 and equal to or less than 0.4 and y is greater than 0 and less than or equal to 3. There is also provided a method of producing a photovoltaic device comprising a photoactive region comprising the perovskite material, and formulations for use in the formation of the perovskite material.

Methods are described that include contacting an alkyl ammonium metal halide film with an alkyl ammonium halide, where the alkyl ammonium metal halide film includes a first halogen and a metal, the alkyl ammonium halide includes a second halogen, such that the contacting forms an alkyl ammonium metal mixed-halide film that interfaces with the alkyl ammonium metal halide film, where the alkyl ammonium metal mixed-halide film includes the first halogen, the second halogen, and the metal.

An aspect of the present disclosure is a method that includes combining a first organic salt (A.sup.1X.sup.1), a first metal salt (M.sup.1(X.sup.2).sub.2), a second organic salt (A.sup.2X.sup.3), a second metal salt (M.sup.2Cl.sub.2), and a solvent to form a primary solution, where A.sup.1X.sup.1 and M.sup.1(X.sup.2).sub.2 are present in the primary solution at a first ratio between about 0.5 to 1.0 and about 1.5 to 1.0, and A.sup.2X.sup.3 to M.sup.2Cl.sub.2 are present in the primary solution at a second ratio between about 2.0 to 1.0 and about 4.0 to 1.0. In some embodiments of the present disclosure, at least one of A.sup.1 or A.sup.2 may include at least one of an alkyl ammonium, an alkyl diamine, cesium, and/or rubidium.

A photoelectric conversion element is provided. The photoelectric conversion element comprises a substrate, a first electrode, an electron transport layer, a hole transport layer, and a second electrode. The electron transport layer comprises a photosensitizing compound. The hole transport layer comprises a basic compound A and an ionic compound B. The basic compound A is represented by the following formula (1):

##STR00001##

where each of R.sub.1 and R.sub.2 independently represents an alkyl group or an aromatic hydrocarbon group, or R.sub.1 and R.sub.2 share bond connectivity to form a nitrogen-containing heterocyclic ring; and the ionic compound B is represented by the following formula (2):

##STR00002##

where X.sup.+ represents a counter cation.

A sensor including a layer of amorphous selenium (a-Se) and at least one charge blocking layer is formed by depositing the charge blocking layer over a substrate prior to depositing the amorphous selenium, enabling the charge blocking layer to be formed at elevated temperatures. Such a process is not limited by the crystallization temperature of a-Se, resulting in the formation of an efficient charge blocking layer, which enables improved signal amplification of the resulting device. The sensor can be fabricated by forming first and second amorphous selenium layers over separate substrates, and then fusing the a-Se layers at a relatively low temperature.

A composition for solar cell electrodes, an electrode formed of the same, and a method of forming an electrode, the composition including a conductive powder; a glass frit; at least one of a cyclosiloxane compound and a silsesquioxane compound; and an organic vehicle.

Embodiments described herein generally relate to monodisperse nanoparticles that are capable of absorbing infrared radiation and generating charge carriers. In some cases, at least a portion of the nanoparticles are nanocrystals. In certain embodiments, the monodisperse, IR-absorbing nanocrystals are formed according to a method comprising a nanocrystal formation step comprising adding a first precursor solution comprising a first element of the nanocrystal to a second precursor solution comprising a second element of the nanocrystal to form a first mixed precursor solution, where the molar ratio of the first element to the second element in the first mixed precursor solution is above a nucleation threshold. The method may further comprise a nanocrystal growth step comprising adding the first precursor solution to the first mixed precursor solution to form a second mixed precursor solution, where the molar ratio of the first element to the second element in the second mixed precursor solution is below the nucleation threshold.