Abstract: A photoelectric conversion film according to the present disclosure includes a perovskite compound including a monovalent formamidinium cation, a Pb cation and an iodide ion, and a substance having Hansen solubility parameters satisfying a dispersion term ?D of 20±0.5 MPa0.5, a polar term ?P of 18±1 MPa0.5 and a hydrogen bonding term ?H of 11±2 MPa0.5.

Abstract: The present disclosure provides a photoelectric conversion film having a high light absorption ability and a long carrier life. A photoelectric conversion film of the present disclosure includes a perovskite compound including a monovalent formamidinium cation, a Pb cation and an iodide ion. The film thickness of the photoelectric conversion film is greater than or equal to 1 ?m. In the photoelectric conversion film, the ratio of root mean square roughness Rq to the film thickness is less than or equal to 0.13.

Abstract: A light absorption material comprising: a compound having a perovskite crystal structure represented by ABX3 where the A site contains (NH2)2CH+, the B site contains Pb2+, and the X site contains I?. A ratio of the number of atoms of I to the number of atoms of Pb measured by an X-ray photoelectron spectroscopy is 2.7 or less, or a ratio of the number of atoms of I to the number of atoms of Pb measured by a Rutherford backscattering spectroscopy is 2.9 or less.

Abstract: A solar cell comprises a first electrode, a second electrode opposite to the first electrode, and a photoabsorber layer located between the first electrode and the second electrode and including a first layer and a second layer. The first layer contains a first compound which has a perovskite structure represented by the composition formula A1M1X13, where A1 is a monovalent cation, M1 is a divalent cation, and X1 is a halogen anion. The second layer contains a second compound which has a perovskite structure represented by the composition formula A2M2X23, where A2 is a monovalent cation, M2 is a divalent cation, and X2 is a halogen anion, and has a different composition from the first compound. At least one of the first compound in the first layer and the second compound in the second layer has a single orientation.

Abstract: A photosensor includes a first electrode, a second electrode that opposes the first electrode, and a photoelectric conversion layer that is disposed between the first electrode and the second electrode and converts incident light into electric charges. At least one electrode selected from the group consisting of the first electrode and the second electrode is light-transmissive. The photoelectric conversion layer contains a perovskite compound. The fluorescence spectrum of the perovskite compound has a first peak at a first wavelength and a second peak at a second wavelength that is longer than the first wavelength. The photoelectric conversion layer is in ohmic contact with each of the first electrode and the second electrode.

Abstract: A solar cell system includes a solar cell that includes a first electrode, a second electrode that faces the first electrode, and a light absorbing layer that is located between the first electrode and the second electrode, and converts light into charges; a power supply that applies voltage between the first electrode and the second electrode; and a voltage controller. The light absorbing layer contains a compound having a perovskite crystal structure represented by AMX3 where A represents a monovalent cation, M represents a divalent cation, and X represents a halogen anion. The voltage controller controls the voltage of the power supply so that during a first period of non-power generation, an electric current of 1 ?A/cm2 or more and 100 ?A/cm2 or less flows in the light absorbing layer in a direction opposite to a direction in which an electric current flows during power generation.

Abstract: A light-absorbing material contains a perovskite compound represented by the composition formula CH3NH3PbI3. The 1H-NMR spectrum, which is obtained by 1H-14N HMQC measurement, of the perovskite compound shows a first peak of 6.2 ppm and a second peak of 6.4 ppm at 25° C., and the peak intensity of the first peak is 15% or more of the peak intensity of the second peak.

Abstract: A light-absorbing material contains a perovskite compound represented by the composition formula HC(NH2)2PbI3. The 1H-NMR spectrum, which is obtained by 1H-14N HMQC measurement, of the perovskite compound shows a first peak of 7.2 ppm and a second peak of 7.4 ppm at 25° C., and the peak intensity of the first peak is 60% or more of the peak intensity of the second peak.

Abstract: A light absorption material comprising: a compound having a perovskite crystal structure represented by ABX3 where the A site contains (NH2)2CH+, the B site contains Pb2+, and the X site contains I?. A ratio of the number of atoms of I to the number of atoms of Pb measured by an X-ray photoelectron spectroscopy is 2.7 or less, or a ratio of the number of atoms of I to the number of atoms of Pb measured by a Rutherford backscattering spectroscopy is 2.9 or less.

Abstract: A solar cell according to one aspect of the present disclosure includes: a first electrode; an electron transport layer on the first electrode; a light-absorbing layer located on the electron transport layer and containing a perovskite type compound; a second electrode on the light-absorbing layer; and a sealing body sealing at least a part of the first electrode, the electron transport layer, the light-absorbing layer, and at least a part of the second electrode. A gas containing oxygen is present between the sealing body and each of the at least a part of the first electrode, the electron transport layer, the light-absorbing layer, and the at least a part of the second electrode. The concentration of the oxygen is 5% or more, and the concentration of water is 300 ppm or less on a volume fraction basis.