ESTI scan facility

Correlations between Photovoltaic Characteristics, Adsorption Number, and Regeneration Kinetics in Dye-Sensitized Solar Cells Revealed by Scanning Photocurrent Microscopy

“…= 1.4, Olympus) to form a diffraction-limited spot size in the electrode plane. It must be emphasized that this laser spot size is approximately an order of magnitude smaller than that in past studies using the light beam induced current technique, 5,7,[9][10][11][12][13][14][15][16][17] which allows us to perform higher spatial resolution photocurrent measurements of the DSCs. As shown in Figure 1, photocurrent measurements of the DSCs were conducted at short-circuit Initially, we measured current density versus voltage (J-V) curves and the excitation rate dependence of the photocurrent under wide illumination of the excitation laser through a shadow mask (i.e., light-exposed volume of approximately 0.2 cm 2 × 100 nm).…”

High resolution laser beam induced current images under trichromatic laser radiation: Approximation to the solar irradiation

“…4 Thus, the LBIC technique has been used for research in different fields related to photovoltaic energy: the superficial study of silicon structures; [5][6][7][8][9] the study of grain boundaries on silicon based solar cells; [10][11][12] the study of polycrystalline solar cells; 1,[13][14][15][16] the study of thin film photovoltaic modules; 17,18 the study of non-silicon based photovoltaic or semiconductor devices 4,19,20 and the study of dye-sensitized solar cells. 23 Three main factors can be associated to the level of photocurrent generated by a photovoltaic surface: ͑a͒ the limit values of photon energy that are necessary for electron transfer between valence and conduction bands, ͑b͒ the intrinsic characteristics of electron-hole recombination, and ͑c͒ photon penetration into the active material. Spatial resolution is a function of the size of the laser spot on the surface, so the smaller it is the greater the capacity to discern differences between adjacent positions by using the photocurrent values generated.…”

“…[22][23][24][25][26] In general, these systems are based on a laser source, which by using different optomechanic systems to prepare the radiation beam, is directed at a system which focalizes it on the active surface of the device. [22][23][24][25][26] In general, these systems are based on a laser source, which by using different optomechanic systems to prepare the radiation beam, is directed at a system which focalizes it on the active surface of the device.…”

Trichromatic High Resolution-LBIC: A System for the Micrometric Characterization of Solar Cells

“…Thus, the LBIC technique allows images of photovoltaic devices to be obtained dependent upon superficial variation in quantum efficiency. Usually photocurrent values are measured at short circuit as it is a linear function of the radiation power in a wide range and the interaction coefficient is proportional to the quantum photoefficiency (Bisconti et al, 1997). Three main factors can be associated to the level of photocurrent generated by a photovoltaic surface: (a) the limit values of photon energy that are necessary for electron transfer between valence and conduction bands, (b) the intrinsic characteristics of electron-hole recombination, and (c) photon penetration into the active material.…”

“…No real irradiation source can simultaneously provide a spectral distribution similar to the emission of the sun with the characteristics of a laser emission in terms of non divergence and Gaussian power distribution. Nowadays, there are several LBIC systems with different configurations which have been developed by research groups and allowing interesting results to be obtained (Bisconti et al, 1997). In general, these systems are based on a laser source which, by using different optomechanical systems to prepare the radiation beam, is directed at a system which focalizes it on the active surface of the device.…”