An image sensor structure, comprising: a substrate; a readout circuit array located on the substrate; a photoelectric layer disposed over the readout circuit array; a filter layer is disposed over the photoelectric layer; wherein the filter layer has a first spectrum of normalized extinction coefficient versus wavelength, the first spectrum defining a first wavelength (λ1) corresponding to a first line passing through a first point and a second point on a curve of the first spectrum of the filter layer, the first point and the second point fall within a wavelength segment of the first spectrum of a peak having the longest wavelength of the first spectrum, the first point aligns with an extinction coefficient of 0.9 and the second point aligns with an extinction coefficient of 0.1, and wherein the first wavelength (λ1) is defined by the first line extending to a position of extinction coefficient of 0; and wherein the photoelectric layer has a second spectrum of normalized extinction coefficient versus wavelength, the second spectrum defining a second wavelength (λ2) corresponding to a second line passing through a third point and a fourth point on a curve of the second spectrum of the photoelectric layer, the third point and the fourth point fall within a wavelength segment of the second spectrum of a peak having the longest wavelength of the second spectrum, the third point aligns with an extinction coefficient of 0.9 and the fourth point aligns with an extinction coefficient of 0.1, and wherein the second wavelength (λ2) is defined by the second line extending to a position of extinction coefficient of 0; and wherein the extinction coefficient is normalized by a maximum extinction coefficient of a peak of the first spectrum or the second spectrum, and wherein the materials of the filter layer and the photoelectric layer are selected such that the second wavelength (λ2) is longer than the first wavelength (λ1). a substrate; a readout circuit array located on the substrate; a photoelectric layer disposed over the readout circuit array; a filter layer is disposed over the photoelectric layer; wherein the filter layer has a first spectrum of normalized extinction coefficient versus wavelength, the first spectrum defining a first wavelength (λ1) corresponding to a first line passing through a first point and a second point on a curve of the first spectrum of the filter layer, the first point and the second point fall within a wavelength segment of the first spectrum of a peak having the longest wavelength of the first spectrum, the first point aligns with an extinction coefficient of 0.9 and the second point aligns with an extinction coefficient of 0.1, and wherein the first wavelength (λ1) is defined by the first line extending to a position of extinction coefficient of 0; and wherein the photoelectric layer has a second spectrum of normalized extinction coefficient versus wavelength, the second spectrum defining a second wavelength (λ2) corresponding to a second line passing through a third point and a fourth point on a curve of the second spectrum of the photoelectric layer, the third point and the fourth point fall within a wavelength segment of the second spectrum of a peak having the longest wavelength of the second spectrum, the third point aligns with an extinction coefficient of 0.9 and the fourth point aligns with an extinction coefficient of 0.1, and wherein the second wavelength (λ2) is defined by the second line extending to a position of extinction coefficient of 0; and wherein the extinction coefficient is normalized by a maximum extinction coefficient of a peak of the first spectrum or the second spectrum, and wherein the materials of the filter layer and the photoelectric layer are selected such that the second wavelength (λ2) is longer than the first wavelength (λ1).